E2 domain of amyloid precursor protein; The E2 domain is the largest of the conserved domains of the amyloid precursor protein. The structure of E2 consists of two coiled-coil sub-structures connected through a continuous helix, and bears an unexpected resemblance to the spectrin family of protein structures.E 2 can reversibly dimerize in solution, and the dimerization occurs along the longest dimension of the molecule in an antiparallel orientation, which enables the N-terminal substructure of one monomer to pack against the C-terminal substructure of a second monomer. The high degree of conservation of residues at the putative dimer interface suggests that the E2 dimer observed in the crystal could be physiologically relevant. Heparin sulfate proteoglycans, the putative ligands for the precursor present in extracellular matrix, bind to E2 at a conserved and positively charged site near the dimer interface.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 312 PPTPVPTDDVDVYFETPADDNEHARFQKAKEQLEVRHHNRMDRVKKEWEEAERQAKNLPKAE-------RQTLTQRFQAM 384
Cdd:pfam12925   1 TTTPPPTDAVDPYFEHPDPRNEHESFKKAKKRLEEKHRERMTKVMKEWEEAEERYQNLPKADpkaaekfKKAMTARFQET 80

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 385 VKSLEKEAASEKQQLVETHLARVEAMLDDRRRIALENYLVALQTDPPRPHRILQALKRYIRAENKDRLHTIRHYQHVLAV 464
Cdd:pfam12925  81 VEALEEEAAAERQQLVETHQQRVEAHLNDRRRDALECYLQALQENPPNPHRILKALKKLLRAEQKDRRHTLRHYRHLLAS 160

                         170       180       190
                  ....*....|....*....|....*....|
gi 2101189867 465 DPEKAAQMKSQVMTHLHVIEERMNQSLSLL 494
Cdd:pfam12925 161 DPEKAEQMKPQVLTHLRVIDRRMNQSLTLL 190

juxtamembrane and transmembrane (JMTM) domain found in amyloid-like protein 2 (APLP-2) and similar proteins; Amyloid-like protein 2 (APLP-2), also called amyloid protein homolog (APPH), or CDEI box-binding protein (CDEBP), may play a role in the regulation of hemostasis. Its soluble form may have inhibitory properties towards coagulation factors. APLP-2 may bind to the DNA 5'-GTCACATG-3'(CDEI box). It inhibits trypsin, chymotrypsin, plasmin, factor XIA, and plasma and glandular kallikrein. This model corresponds to juxtamembrane and transmembrane (JMTM) domain of APLP-2, which consists of the intact transmembrane (TM) domain with adjacent N-terminal juxtamembrane (JM) region.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 633 NDNSLRDDFSFSSSALIGLLVIAVAIATVIVISLVMLRKRQYGTISHGIVEVDPMLTPEERHLNKMQNHGYENPTYKYLE 712
Cdd:cd21709     1 SDGPLRDDFSFSSSALIGLLVIAVAIATVIVISLVLLRKRQYGTISHGIVEVDPMLTPEERHLNKMQNHGYENPTYKYLE 80

                  .
gi 2101189867 713 Q 713
Cdd:cd21709    81 Q 81

E2 domain of amyloid precursor protein; The E2 domain is the largest of the conserved domains of the amyloid precursor protein. The structure of E2 consists of two coiled-coil sub-structures connected through a continuous helix, and bears an unexpected resemblance to the spectrin family of protein structures.E 2 can reversibly dimerize in solution, and the dimerization occurs along the longest dimension of the molecule in an antiparallel orientation, which enables the N-terminal substructure of one monomer to pack against the C-terminal substructure of a second monomer. The high degree of conservation of residues at the putative dimer interface suggests that the E2 dimer observed in the crystal could be physiologically relevant. Heparin sulfate proteoglycans, the putative ligands for the precursor present in extracellular matrix, bind to E2 at a conserved and positively charged site near the dimer interface.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 312 PPTPVPTDDVDVYFETPADDNEHARFQKAKEQLEVRHHNRMDRVKKEWEEAERQAKNLPKAE-------RQTLTQRFQAM 384
Cdd:pfam12925   1 TTTPPPTDAVDPYFEHPDPRNEHESFKKAKKRLEEKHRERMTKVMKEWEEAEERYQNLPKADpkaaekfKKAMTARFQET 80

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 385 VKSLEKEAASEKQQLVETHLARVEAMLDDRRRIALENYLVALQTDPPRPHRILQALKRYIRAENKDRLHTIRHYQHVLAV 464
Cdd:pfam12925  81 VEALEEEAAAERQQLVETHQQRVEAHLNDRRRDALECYLQALQENPPNPHRILKALKKLLRAEQKDRRHTLRHYRHLLAS 160

                         170       180       190
                  ....*....|....*....|....*....|
gi 2101189867 465 DPEKAAQMKSQVMTHLHVIEERMNQSLSLL 494
Cdd:pfam12925 161 DPEKAEQMKPQVLTHLRVIDRRMNQSLTLL 190

juxtamembrane and transmembrane (JMTM) domain found in amyloid-like protein 2 (APLP-2) and similar proteins; Amyloid-like protein 2 (APLP-2), also called amyloid protein homolog (APPH), or CDEI box-binding protein (CDEBP), may play a role in the regulation of hemostasis. Its soluble form may have inhibitory properties towards coagulation factors. APLP-2 may bind to the DNA 5'-GTCACATG-3'(CDEI box). It inhibits trypsin, chymotrypsin, plasmin, factor XIA, and plasma and glandular kallikrein. This model corresponds to juxtamembrane and transmembrane (JMTM) domain of APLP-2, which consists of the intact transmembrane (TM) domain with adjacent N-terminal juxtamembrane (JM) region.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 633 NDNSLRDDFSFSSSALIGLLVIAVAIATVIVISLVMLRKRQYGTISHGIVEVDPMLTPEERHLNKMQNHGYENPTYKYLE 712
Cdd:cd21709     1 SDGPLRDDFSFSSSALIGLLVIAVAIATVIVISLVLLRKRQYGTISHGIVEVDPMLTPEERHLNKMQNHGYENPTYKYLE 80

                  .
gi 2101189867 713 Q 713
Cdd:cd21709    81 Q 81

Kunitz domain found in the amyloid-beta precursor protein (ABPP) subfamily; This subfamily includes the amyloid-beta precursor protein (ABPP, also called APP, APPI, Alzheimer disease amyloid protein, amyloid-beta A4 protein, cerebral vascular amyloid peptide (CVAP), protease nexin II (PN2)), as well as amyloid-like protein 2 (APLP2, also called amyloid protein homolog or APPH), among others. ABPP/APPI is an inhibitor of serine proteases such as anionic and cationic trypsins. For example, APPI-4M is a variant that specifically inhibits Kallikrein (KLK)-related peptidase 6 (KLK6), which is highly upregulated in several types of cancer where its increased activity promotes cancer invasion and metastasis. Amyloid-like protein 2 (APLP2) inhibits trypsin, chymotrypsin, plasmin, factor XIA, and plasma and glandular kallikrein, and may play a role in the regulation of hemostasis. Proteins in this subfamily contain a single Kunitz domain, with a structure similar to those of other Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor), showing an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 2101189867 256 VCSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22607     1 VCSEQAETGPCRAMMPRWYFDVTEGKCAPFIYGGCGGNRNNFESEEYCMAVC 52

Kunitz/Bovine pancreatic trypsin inhibitor domain; Indicative of a protease inhibitor, usually a serine protease inhibitor. Structure is a disulfide rich alpha+beta fold. BPTI (bovine pancreatic trypsin inhibitor) is an extensively studied model structure. Certain family members are similar to the tick anticoagulant peptide (TAP). This is a highly selective inhibitor of factor Xa in the blood coagulation pathways. TAP molecules are highly dipolar, and are arranged to form a twisted two- stranded antiparallel beta-sheet followed by an alpha helix.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 2101189867 256 VCSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVCK 308
Cdd:pfam00014   1 ICSLPPDSGPCKASIPRWYYNPTTGTCEPFTYGGCGGNANNFESLEECESTCR 53

Chromosome segregation ATPase Smc [Cell cycle control, cell division, chromosome partitioning];

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 336 RFQKAKEQLEVRHHN----RMDRVKKEWEEAERQAknlpkAERQTLTQRFQAMVKSLEKEAASEKQQLVETHLaRVEAML 411
Cdd:COG1196   214 RYRELKEELKELEAEllllKLRELEAELEELEAEL-----EELEAELEELEAELAELEAELEELRLELEELEL-ELEEAQ 287

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 412 DDRRRIALEnyLVALQTDpprpHRILQALKRYIRAENKDRLHTIRHYQHVLAVDPEKAAQMKSQVM---THLHVIEERMN 488
Cdd:COG1196   288 AEEYELLAE--LARLEQD----IARLEERRRELEERLEELEEELAELEEELEELEEELEELEEELEeaeEELEEAEAELA 361

                         170       180       190
                  ....*....|....*....|....*....|...
gi 2101189867 489 QSLSLLYKVAYVAEEIQSEIDELLQEQRADMDQ 521
Cdd:COG1196   362 EAEEALLEAEAELAEAEEELEELAEELLEALRA 394

E2 domain of amyloid precursor protein; The E2 domain is the largest of the conserved domains of the amyloid precursor protein. The structure of E2 consists of two coiled-coil sub-structures connected through a continuous helix, and bears an unexpected resemblance to the spectrin family of protein structures.E 2 can reversibly dimerize in solution, and the dimerization occurs along the longest dimension of the molecule in an antiparallel orientation, which enables the N-terminal substructure of one monomer to pack against the C-terminal substructure of a second monomer. The high degree of conservation of residues at the putative dimer interface suggests that the E2 dimer observed in the crystal could be physiologically relevant. Heparin sulfate proteoglycans, the putative ligands for the precursor present in extracellular matrix, bind to E2 at a conserved and positively charged site near the dimer interface.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 312 PPTPVPTDDVDVYFETPADDNEHARFQKAKEQLEVRHHNRMDRVKKEWEEAERQAKNLPKAE-------RQTLTQRFQAM 384
Cdd:pfam12925   1 TTTPPPTDAVDPYFEHPDPRNEHESFKKAKKRLEEKHRERMTKVMKEWEEAEERYQNLPKADpkaaekfKKAMTARFQET 80

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 385 VKSLEKEAASEKQQLVETHLARVEAMLDDRRRIALENYLVALQTDPPRPHRILQALKRYIRAENKDRLHTIRHYQHVLAV 464
Cdd:pfam12925  81 VEALEEEAAAERQQLVETHQQRVEAHLNDRRRDALECYLQALQENPPNPHRILKALKKLLRAEQKDRRHTLRHYRHLLAS 160

                         170       180       190
                  ....*....|....*....|....*....|
gi 2101189867 465 DPEKAAQMKSQVMTHLHVIEERMNQSLSLL 494
Cdd:pfam12925 161 DPEKAEQMKPQVLTHLRVIDRRMNQSLTLL 190

juxtamembrane and transmembrane (JMTM) domain found in amyloid-like protein 2 (APLP-2) and similar proteins; Amyloid-like protein 2 (APLP-2), also called amyloid protein homolog (APPH), or CDEI box-binding protein (CDEBP), may play a role in the regulation of hemostasis. Its soluble form may have inhibitory properties towards coagulation factors. APLP-2 may bind to the DNA 5'-GTCACATG-3'(CDEI box). It inhibits trypsin, chymotrypsin, plasmin, factor XIA, and plasma and glandular kallikrein. This model corresponds to juxtamembrane and transmembrane (JMTM) domain of APLP-2, which consists of the intact transmembrane (TM) domain with adjacent N-terminal juxtamembrane (JM) region.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 633 NDNSLRDDFSFSSSALIGLLVIAVAIATVIVISLVMLRKRQYGTISHGIVEVDPMLTPEERHLNKMQNHGYENPTYKYLE 712
Cdd:cd21709     1 SDGPLRDDFSFSSSALIGLLVIAVAIATVIVISLVLLRKRQYGTISHGIVEVDPMLTPEERHLNKMQNHGYENPTYKYLE 80

                  .
gi 2101189867 713 Q 713
Cdd:cd21709    81 Q 81

juxtamembrane and transmembrane (JMTM) domain found in amyloid-like protein 1 (APLP-1) and similar proteins; Amyloid-like protein 1 (APLP-1), also called APLP, may play a role in postsynaptic function. It couples to JIP signal transduction through C-terminal binding. APLP-1 may interact with cellular G-protein signaling pathways. It can regulate neurite outgrowth through binding to components of the extracellular matrix such as heparin and collagen I. This model corresponds to the juxtamembrane and transmembrane (JMTM) domain of APLP-1, which consists of the intact transmembrane (TM) domain with adjacent N-terminal juxtamembrane (JM) region.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 2101189867 642 SFSSSALIGLLVIAVAIATVIVISLVMLRKRQYGTISHGIVEVDPMLTPEERHLNKMQNHGYENPTYKYLEQ 713
Cdd:cd21708    14 TFNRGALIGLLVVAVAVAMVIVISLLLVRRKPYGTISHGIVEVDPMLTPEERQLSKMQNHGYENPTYRFLEE 85

Copper-binding of amyloid precursor, CuBD; This short domain, part of the extra-cellular N-terminus of the amyloid precursor protein, APP, can bind both copper and zinc, CuBD. The structure of Cu2+-bound CuBD reveals that the metal ligands are His147, His151, Tyr168 and two water molecules, which are arranged in a square pyramidal geometry. The structure of Cu+-bound CuBD is almost identical to the Cu2+-bound structure except for the loss of one of the water ligands. The geometry of the site is unfavourable for Cu+, thus providing a mechanism by which CuBD could readily transfer Cu ions to other proteins.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2101189867  92 CRFFHRERMDVCKSHQYWHTVAKEACLTEGTILHSYGMLLPCGVDQFHGTEYVCCP 147
Cdd:pfam12924   1 CKFDHKHNMDVCESHQHWHATAKEACAARGMVLHSFGMLLPCGIDLFTGVEFVCCP 56

Beta-amyloid precursor protein C-terminus; This is the amyloid, C-terminal, protein of the beta-Amyloid precursor protein (APP) which is a conserved and ubiquitous transmembrane glycoprotein strongly implicated in the pathogenesis of Alzheimer's disease but whose normal biological function is unknown. The C-terminal 100 residues are released and aggregate into amyloid deposits which are strongly implicated in the pathology of Alzheimer's disease plaque-formation. The domain is associated with family A4_EXTRA, pfam02177, further towards the N-terminus.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 2101189867 662 IVISLVMLRKR-QYGTISHGIVEVDPMLTPEERHLNKMQNHGYENPTYKYLE 712
Cdd:pfam10515   1 IVVGMALLRRRaARSPSAHGFVEVDPNVTPEERHVANMQVNGYENPTYKYFE 52

Kunitz/Bovine pancreatic trypsin inhibitor (BPTI) domain; This family contains the Kunitz domain which is a common structural fold found in a family of reversible serine protease inhibitors. This domain is thought to have evolved over 500 million years and is ubiquitous in all kingdoms of life and has been incorporated into many different genes. In general, each domain is encoded by a single exon. Some genes encode proteins with a single Kunitz domain, e.g. bovine pancreatic trypsin inhibitor (BPTI), trophoblast Kunitz domain protein (TKDP), amyloid beta-protein precursor (ABPP), as well as Kunitz-type venom peptides such as dendrotoxin. Genes that encode multiple Kunitz domains include hepatocyte growth factor activator inhibitors HAI1 and HAI2 (two domains), tissue factor pathway inhibitor TFPI1 and TFPI2 (three domains) and Caenorhabditis elegans papilin (eleven domains). In addition, the Kunitz domain has been integrated into multi-domain proteins, e.g. the collagen alpha3(VI), alpha1(VII) and alpha1(XXVIII) chains, WFIKKN1 (containing WAP, Follistatin/Kazal, Immunoglobulin, two Kunitz and NTR domains) and papilin. Furthermore, each domain within a multi-Kunitz domain protein may exhibit different protease activity, such as for the three tandemly repeated domains within both tissue factor pathway inhibitors 1 and 2. The Kunitz domain is a representative of alpha/beta proteins with irregular secondary structure stabilized by three disulfide bonds and presenting three peptide loops that can be varied without introducing much destabilization to the scaffold. Protease inhibitors meet the scaffold criteria in that they are small, stable and capable of evolving the binding activity of exposed peptide loops through targeted randomization to construct combinatorial libraries. Kunitz domain-based scaffolds have been successfully utilized to construct and select a library of protease inhibitors with the potential for therapeutic application.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2101189867 257 CSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd00109     1 CLLPPDPGPCRAYFPRWYYNSETGQCEEFIYGGCGGNANNFETKEECEATC 51

Kunitz-type domain 2 (KD2) of hepatocyte growth factor activator inhibitor type 2 (HAI-2), and similar proteins; This model includes Kunitz domain 2 (KD2) of hepatocyte growth factor activator inhibitor type 2 (HAI-2 or HAI2, also known as placental bikunin or Kunitz-type protease inhibitor 2). HAI-2 is composed of two Kunitz domains that strongly inhibit many serine proteases with sub-nanomolar affinities. It has been found to be a natural tumor suppressor in renal cell carcinoma, breast cancer and prostate cancer, the loss of which leads to tumor growth and progression attributable at least in part to increased MET signaling. HAI-2 is a specific substrate of mesotrypsin which is up-regulated with progression in prostate cancers and shown to contribute to invasion and metastasis; these activities of mesotrypsin may in part be mediated through cleavage and inactivation of HAI-2, resulting in increases in hetatocyte growth factor/scatter factor (HGF/SF) activation and MET signaling. HAI-2 is a physiological inhibitor of hepsin and matriptase, two type II transmembrane serine proteases that, like HGF activator, can convert latent pro-HGF/SF into the two-chain active signaling heterodimer. KD2 is similar to KD1, whose structure is similar to those of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor), showing an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2101189867 257 CSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22622     3 CAAPRVTGPCRAAFPRWYYDPESQSCKEFIYGGCRGNKNNYLSEEECMDRC 53

Stichodactyla helianthus Kunitz inhibitor protein ShPI-1, Heteractis crispa protease inhibitor stichotoxin-Hcr2e, and similar proteins; This model includes Kunitz inhibitor protein ShPI-1, the major protease inhibitor from the sea anemone Stichodactyla helianthus, as well as protease inhibitor stichotoxin-Hcr2e (also called PI- stichotoxin-Hcr2e, PI-SHTX-Hcr2e, or Kunitz-type serine protease inhibitor InhVJ) and HCRG1 from Heteractis crispa. ShPI-1 has an unusually broad specificity toward several serine proteases, including trypsin, chymotrypsin, human neutrophil elastase, kallikrein and plasmin, and can also bind aspartic and cysteine proteases, such as pepsin and papain, respectively. PI-SHTX-Hcr2e and HCRG1 inhibit trypsin and chymotrypsin, but do not inhibit the serine proteases plasmin, thrombin, kallikrein, the cysteine proteinase papain, and the aspartic protease pepsin. The structures of these domains are similar to those of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor), showing an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 2101189867 256 VCSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVCK 308
Cdd:cd22618     1 ICSEPKVVGPCKAYFPRFYFDSETGKCTPFIYGGCGGNGNNFETLHACRAICR 53

third Kunitz domain of Carboxypeptidase Inhibitor SmCI and similar domains; This group includes Sabellastarte magnifica carboxypeptidase inhibitor (SmCI), Bombyx mori cocoon shell-associated trypsin inhibitor (CSTI), Bombus terrestris Kunitz-type serine protease inhibitor Bt-KTI, and similar domains. SmCI is a tri-domain BPTI-Kunitz inhibitor capable of inhibiting serine proteases and A-like metallocarboxypeptidases. While the BPTI-Kunitz family of proteins includes voltage gated channel blockers and inhibitors of serine proteases, SmCI is the only BPTI-Kunitz protein capable of inhibiting metallocarboxypeptidases. Binding studies show that SmCI is able to bind three trypsin molecules under saturating conditions, but only one elastase interacts with the inhibitor. Additionally, SmCI can bind serine proteases and carboxypeptidases at the same time (at least in the ratio 1:1:1), thus becoming the first protease inhibitor that simultaneously blocks these two mechanistic classes of enzymes. CSTI and Bt-KTI are single Kunitz domain proteins that inhibit trypsin; in addition, Bt-KTI also inhibits plasmin. This model contains the third Kunitz domain of SmCI which has a structure similar to those of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor), showing an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 2101189867 256 VCSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22603     2 DCLLPSETGPCKGSFPRYYYDKETGKCKEFIYGGCQGNANNFETKEECERAC 53

second Kunitz domain of WAP, Kazal, immunoglobulin, Kunitz and NTR domain-containing proteins; This subfamily includes WAP, Kazal, immunoglobulin, Kunitz and NTR domain-containing protein 1 (WFIKKN1, WFKN1), WFIKKN2 (WFKN2), and similar proteins. WFIKKN proteins are protease inhibitors that contain two distinct Kunitz-type protease inhibitor domains. They may have serine protease- and metalloprotease-inhibitor activity. This model represents the second Kunitz (KU2) domain, which has been shown to inhibit trypsin, but not chymotrypsin, elastase, plasmin, pancreatic kallikrein, lung tryptase, plasma kallikrein, thrombin, urokinase or tissue plasminogen activator. However, the inhibition constant of this domain for bovine trypsin is about five orders of magnitudes lower than that of bovine pancreatic trypsin inhibitor (BPTI) for trypsin. This could be due to unfavorable side-chain conformation of a tryptophan at P2' site which is incompatible with a trypsin complex; typical trypsin inhibitors of the Kunitz family feature a tyrosine residue or other less bulky residues at this site. The structure of KU2 is similar to those of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor), showing an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 2101189867 256 VCSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22606     1 ICSLPAVQGPCKAWEPRWAYNSLLKQCQSFVYGGCEGNENNFESKEACEDAC 52

first Kunitz domain of Rhipicephalus microplus boophilin and similar proteins; This group includes venom serine protease inhibitors such as Rhipicephalus microplus and Ixodes scapularis boofilin, among others. Boophilin prevents blood clot formation to allow successful feeding and digestion through its inhibition activity of thrombin and other host anticoagulating factors like kallikrein, coagulation factor VII, or plasmin; it interacts with the host thrombin and trypsin. The structures of these domains are similar to those of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor), showing an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds. Rhipicephalus microplus boophilin contains two Kunitz domains; this model represents the first repeat.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 2101189867 255 AVCSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVCK 308
Cdd:cd22599     4 GICRLPADEGICRALIPRFYFNTETGQCTEFIYGGCGGNENNFETIEECEKACG 57

Kunitz domain 1 of hepatocyte growth factor activator inhibitor-1 (HAI-1); This model includes Kunitz domain 1 (KD1) of hepatocyte growth factor activator inhibitor type 1 (HAI1 or HAI-1, also known as Kunitz-type protease inhibitor 1), a membrane-bound multidomain protein essential to the integrity of the basement membrane during placental development. HAI-1 contains an extracellular region and several internal domains that include two Kunitz domains separated in sequence but spatially closed to each other, and their interdomain interactions have evolved to stimulate the inhibitory activity of an integrated Kunitz. KD1, the major inhibitory domain of HAI-1, is involved in auto-inhibition of the extracellular region via steric blockage of its active site in the HAI-1 compact tertiary structure; presence of the target protease causes changes in the HAI-1 structure to an extended conformation. HAI-1 has been shown to inhibit several serine proteases such as matripase, hepsin, trypsin, hepatocyte growth factor activator (HGFA), and prostasin. It is also important in maintaining postnatal homeostasis in many tissues, including keratinization of the epidermis, hair development, colonic epithelium integrity, proliferation and cell fate of neural progenitor cells, and tissue injury and repair. The interaction between HAI-1 and matriptase is critical for tissue morphogenesis and cellular biology. HAI-1:matriptase ratio imbalance results in tumorigenesis; slight overexpression of matriptase relative to HAI-1 causes spontaneous squamous cell carcinoma, a phenotype that can be effectively reversed back to wild type by additional expression of HAI-1, indicating the need for a tight functional relationship between the two to maintain homeostasis. The structures of these domains are similar to those of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor), showing an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 2101189867 263 TGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVCK 308
Cdd:cd22623    12 VGPCRGSFPRWHYNAASGKCEEFVFGGCKGNKNNYLSEEECLSACR 57

Kunitz-type domain from the alpha3 chain of human type VI collagen, and similar proteins; This model includes the Kunitz-type domain from the alpha3 chain of type VI collagen (collagen alpha 3(VI) chain), encoded by COL6A3 gene. Collagen VI is a widely expressed member of the triple helix-containing protein superfamily of collagens and forms beaded microfibrils that anchor large interstitial structures. Immediately after fibril formation, the Kunitz domain can be cleaved off. Mutations in the alpha1, alpha2, and alpha3 chains of collagen VI cause myopathies ranging from the severe Ullrich congenital muscular dystrophy to the milder Bethlem myopathy, including intermediate forms. Early onset isolated dystonia, a neurological disease, has been shown to be caused by mutations in the alpha3 chain. Findings also indicated potential associations between COL6A3 polymorphisms and lung cancer risk. This domain is similar to that of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor), showing an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 2101189867 256 VCSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22629     2 ICKLPKDEGTCRDFVLKWYYDPETKSCARFWYGGCGGNENRFDSQEECEKVC 53

bovine pancreatic trypsin inhibitor; This model contains bovine pancreatic trypsin inhibitor (BPTI, also known as pancreatic Kunitz inhibitor, aprotinin, or trypsin-kallikrein inhibitor), a small protein that inhibits the action of the trypsin, and is thus a member of the serine protease family of inhibitors. This class of enzymes contains conserved cysteine residues that form 3 disulfide bonds to stabilize the three-dimensional structure. BPTI has a relatively broad specificity, inhibiting trypsin as well as chymotrypsin, and elastase-like serine (pro)enzymes capable of very different primary specificity. It reacts rapidly with serine proteases to form stable complexes, but the enzyme:inhibitor complex formation may involve several intermediates corresponding to discrete reaction steps. Furthermore, BPTI inhibits the nitric oxide synthase type-I and -II action, and impairs K+ transport by Ca2+-activated K+ channels. Clinically, BPTI is used in certain surgical interventions, such as cardiopulmonary surgery and orthotopic liver transplantation since it significantly reduces hemorrhagic complications.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2101189867 257 CSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22592     2 CLEPPYTGPCKARIIRYFYNAKSGLCETFVYGGCRAKRNNFLSAEDCMRTC 52

Kunitz domain 2 (KD2) of tissue factor pathway inhibitor 2 (TFPI2) and similar proteins; This model represents the Kunitz-type domain 2 (KD2) of tissue factor pathway inhibitor 2 (TFPI2 or TFPI-2) and similar proteins. TFPI2 exhibits inhibitory activity primarily toward trypsin, plasmin, and factor VIIa (FVIIa)/tissue factor (TF) via its KD1. It is believed to be the major inhibitor of plasmin in the extracellular matrix (ECM) but has little inhibitory activity toward urokinase-type plasminogen activator, tissue-type plasminogen activator, or thrombin. While TFPI2 specifically inhibits the proteases via the P1 arginine residue in KD1, domains KD2 and KD3 appear to have no discernible inhibitory activity and may serve to bind to nearby proteins to localize TFPI2 in the ECM. This domain is similar to that of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor) that shows an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 2101189867 256 VCSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22617     3 VCREVPDEGPCRALITRYFYNMTSMRCEEFTYGGCYGNGNNFRDKSSCISAC 54

Kunitz-type actitoxins such as Anemonia viridis U-actitoxin-Avd3l, and similar proteins; This model includes the Kunitz-type actitoxins such as Anemonia viridis U-actitoxin-Avd3l (also called U-AITX-Avd3l or AsKC9), Anthopleura elegantissima KappaPI-actitoxin-Ael3a (also called KappaPI-AITX-Ael3a or Kunitz-type serine protease inhibitor APEKTx1) and Anthopleura aff. xanthogrammica PI-actitoxin-Axm2b (also called PI-AITX-Axm2b or Kunitz-type proteinase inhibitor AXPI-II). U-AITX-Avd3l and KappaPI-AITX-Ael3a are dual-function toxins that inhibit both the serine protease trypsin and voltage-gated potassium channels Kv1.2/KCNA2. These proteins are similar to Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor) that shows an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 2101189867 264 GPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22633    12 GGCRARFPRYYYNSSTRRCEKFRYGGCGGNANNFHTLEECEKVC 55

first Kunitz domain of Carboxypeptidase Inhibitor SmCI and similar domains; This group includes Sabellastarte magnifica carboxypeptidase inhibitor (SmCI), a tri-domain BPTI-Kunitz inhibitor capable of inhibiting serine proteases and A-like metallocarboxypeptidases. While the BPTI-Kunitz family of proteins includes voltage gated channel blockers and inhibitors of serine proteases, SmCI is the only BPTI-Kunitz protein capable of inhibiting metallocarboxypeptidases. Binding studies show that SmCI is able to bind three trypsin molecules under saturating conditions, but only one elastase interacts with the inhibitor. Additionally, SmCI can bind serine proteases and carboxypeptidases at the same time (at least in the ratio 1:1:1), thus becoming the first protease inhibitor that simultaneously blocks these two mechanistic classes of enzymes. This model contains the first Kunitz domain of SmCI, which has a structure similar to those of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor), showing an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 2101189867 255 AVCSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22601     2 DVCDLPADRGPCTAYIPRWFYNKTTKKCEKFVYGGCQGNKNRFETKDDCLANC 54

early lactation protein (ELP), colostrum trypsin inhibitor (CTI), and similar proteins; This model includes the Kunitz-type proteins, colostrum trypsin inhibitor (CTI, also called colostrum BPI) and early lactation protein (ELP). In marsupials, the ELP gene is expressed in the mammary gland and the protein is secreted into milk during early lactation. Mature ELP shares approximately 55.4% similarity with the colostrum-specific bovine CTI protein. Marsupial ELP and eutherian CTI both have a single Kunitz domain and are secreted only during the early lactation phases, suggesting that this protein may have an important role in the immunologically immature young of these species. These proteins are similar to Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor) that shows an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 2101189867 255 AVCSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVCK 308
Cdd:cd22632     2 SLCQLPPARGPCRSNILRYFYNSTSRECEPFIYGGCNGNANNFETVEMCLRTCK 55

Kunitz-type domain from the alpha6 chain of human type VI collagen, and similar proteins; This model includes the Kunitz-type domain from the alpha6 chain of type VI collagen (collagen alpha 6(VI) chain), encoded by COL6A6 gene, and similar proteins. Collagen VI is a widely expressed member of the triple helix-containing protein superfamily of collagens and forms beaded microfibrils that anchor large interstitial structures. Immediately after fibril formation, the Kunitz domain can be cleaved off. This domain is similar to that of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor) that shows an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 2101189867 256 VCSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVCKK 309
Cdd:cd22630     2 ACSLDQDEGECQNYVLKWYYDQEQKECSQFWYGGCGGNKNRFETQEECEALCVK 55

conkunitzin-S1 and -S2, and similar proteins; This model includes Kunitz-type conkunitzin-S1 (Cs1) and -S2 (Cs2). Conkunitzins are pore-modulating toxins that block voltage-dependent potassium channels (Kvs) by exploiting inherent slow inactivation to block K+ channels. Cs1 binds to the channel turrets and disrupts the structural water hydrogen-bonding network, exposing the peripheral water pockets of ion channels and triggering an asymmetric collapse of the pore. Conus bullatus conkunitzin-B1, expressed in the venom duct, specifically blocks voltage-activated potassium channels (Kv) of the Shaker family. Members of this subfamily contain 2 disulfide bonds instead of the 3 present in most Kunitz domain proteins.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2101189867 257 CSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22593     1 CSLPLDEGSGNSSLTRWYYDPKKGQCKPFTYKGKGGNENNFLTKEDCEETC 51

Kunitz protease inhibitor (KPI) domain 3 (KPI-3 or K3) of tissue factor pathway inhibitor (TFPI) and TFPI2, and similar proteins; This model represents the third Kunitz-type domain (K3 or KPI-3) of tissue factor pathway inhibitor (TFPI or TFPI1), also known as extrinsic pathway inhibitor (EPI) or lipoprotein-associated coagulation inhibitor (LACI), and of TFPI2 (or TFPI-2). TFPI1 down-regulates the extrinsic coagulation pathway via inhibition of activated factor X (FXa or Xa) and FVIIa (VIIa). It inhibits activated FXa via a "slow-tight binding mechanism", i.e. rapid formation of a loose FXa-TFPI1 complex that then slowly isomerizes to a tight FXa-TFPI1* complex. Subsequent inhibition of FVIIa is facilitated by the presence of tissue factor (TF) and FXa, which together rapidly and efficiently form a quaternary FXa-TFPI1-TF-FVIIa complex in which the activity of FXa and FVIIa are inhibited. TFPI1 consists of 3 Kunitz-type protease inhibitor (KPI) domains in a tandem arrangement; while the K1 domain of TFPI has been shown to bind and inhibit FVIIa and the K2 domain similarly inhibits FXa, the K3 domain has no known inhibitory function. However, Protein S, which functions as a cofactor for TFPI to efficiently enhance TFPI inhibition of FXa and FXa activated TF-VIIa, is dependent on direct interactions with two important residues within K3, a Glutamate and an Arginine. This model also includes TFPI2 Kunitz domain 3 (KD3). TFPI2 exhibits inhibitory activity primarily toward trypsin, plasmin, and factor VIIa (FVIIa)/tissue factor (TF) via its KD1. It is believed to be the major inhibitor of plasmin in the extracellular matrix (ECM) but has little inhibitory activity toward urokinase-type plasminogen activator, tissue-type plasminogen activator, or thrombin. While TFPI2 specifically inhibits the proteases via the P1 arginine residue in KD1, domains KD2 and KD3 appear to have no discernible inhibitory activity and may serve to bind to nearby proteins to localize TFPI2 in the ECM. The structure of this domain is similar to that of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor), showing an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2101189867 257 CSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22615     4 CLSPKDEGLCSASVTRYYYNSATKTCEPFNYTGCGGNNNNFTSKKDCLRVC 54

venom Kunitz-type proteins such as textilinin, BF9 and PILP; This group includes toxins isolated from snake venoms, such as textilinin, vestiginin, spermatin, mulgin, venom basic protease inhibitor IX (BF9), and protease inhibitor-like protein (PILP), among others. Pseudonaja textilis textilinin-1 is a Kunitz-type serine protease inhibitor that binds to and blocks the activity of a range of serine proteases, including plasmin and trypsin. Ability of testilinin to inhibit plasmin, a protease involved in fibrinolysis, raises the possibility that it may be used as an alternative to aprotinin (Trasylol), which is a systemic antibleeding agent in surgery. Also included is the Bungarus fasciatus fraction IX (BF9), a chymotrypsin inhibitor that binds chymotrypsin but not trypsin. Protease inhibitor-like proteins PILP-1 and PILP-2 show weak binding and inhibition of matrix metalloproteinase-2 (MMP-2) and show an activity in inhibiting migration and invasion of neuroblastoma; they do not inhibit chymotrypsin or trypsin. The structures of these toxins are similar to those of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor), showing an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2101189867 257 CSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22594     5 CELPADPGPCNAYKPAFYYNPASHKCLEFIYGGCGGNANNFKTIDECHRTC 55

Kunitz-type domain from the alpha6 chain of fish type VI collagen, and similar proteins; This model includes the Kunitz-type domain from the alpha6 chain of type VI collagen (collagen alpha 6(VI) chain) and similar proteins. Collagen VI is a widely expressed member of the triple helix-containing protein superfamily of collagens and forms beaded microfibrils that anchor large interstitial structures. Immediately after fibril formation, the Kunitz domain can be cleaved off. This domain is similar to that of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor) that shows an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2101189867 257 CSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22631     1 CLLGQDAGSCQNYTMMWFFDSKQGRCSRFWYGGCGGNANRFETQEECENLC 51

second Kunitz domain of Carboxypeptidase Inhibitor SmCI and similar domains; This group includes Sabellastarte magnifica carboxypeptidase inhibitor (SmCI), a tri-domain BPTI-Kunitz inhibitor capable of inhibiting serine proteases and A-like metallocarboxypeptidases. While the BPTI-Kunitz family of proteins includes voltage gated channel blockers and inhibitors of serine proteases, SmCI is the only BPTI-Kunitz protein capable of inhibiting metallocarboxypeptidases. Binding studies show that SmCI is able to bind three trypsin molecules under saturating conditions, but only one elastase interacts with the inhibitor. Additionally, SmCI can bind serine proteases and carboxypeptidases at the same time (at least in the ratio 1:1:1), thus becoming the first protease inhibitor that simultaneously blocks these two mechanistic classes of enzymes. This model contains the second Kunitz domain of SmCI, which has a structure similar to those of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor), showing an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2101189867 257 CSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22602     1 CSLPSKVGPCRVSARRWFHNPETEKCEVFIYGGCHGNANRFATETECQEVC 51

first Kunitz domain of WAP, Kazal, immunoglobulin, Kunitz and NTR domain-containing proteins; This subfamily includes WAP, Kazal, immunoglobulin, Kunitz and NTR domain-containing protein 1 (WFIKKN1, WFKN1), WFIKKN2 (WFKN2), and similar proteins. WFIKKN proteins are protease inhibitors that contain two distinct Kunitz-type protease inhibitor domains. They may have serine protease- and metalloprotease-inhibitor activity. This model represents the first Kunitz domain that is similar to Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor) that shows an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2101189867 257 CSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22605     2 CLKEPDREDCGEEQVRWYFDAKRGNCFTFTYGGCDGNRNHFETYEECRLAC 52

dendrotoxins I, K, B and similar proteins; This group includes toxins isolated from snake venoms, such as dendrotoxins (DTXs) I, K and B, mambaquaretin-1 (MQ-1) and calcicludine. The dendrotoxins have little or no anti-protease activity but have been shown to block certain subtypes of voltage dependent potassium channels in neurons. Dendroaspis angusticeps (green mamba) alpha-dendrotoxin is a neurotoxin that enhances acetylcholine release at neuromuscular junctions. Studies with cloned K(+) channels show that this toxin blocks Kv1.1, Kv1.2 and Kv1.6 channels in the nanomolar range, whereas Dendroaspis polylepis (black mamba) dendrotoxin K preferentially blocks Kv1.1 channels. Also, structural analogs of dendrotoxins have facilitated defining the molecular recognition properties of different types of K(+) channels, and therefore, dendrotoxins are widely used as probes for studying the function of K(+) channels in physiology and pathophysiology. The structures of these toxins are similar to that of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor), showing an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2101189867 257 CSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVC 307
Cdd:cd22595     4 CKLPVRPGPCKAFISAFYYNWKAKKCHPFTYSGCGGNANRFKTIEECRRTC 54

first Kunitz domain of bikunin and similar proteins; This subfamily includes the N-terminal domain of bikunin (also known as inter-alpha-trypsin inhibitor light chain (ITI-LC) or urinary trypsin inhibitor), a plasma protease inhibitor, that is associated with inflammation and stabilizes the extracellular matrix. It is encoded together with alpha-1-microglobulin (A1M) by an alpha-1-microglobulin/bikunin precursor (AMBP) gene that is tightly controlled by several hepatocyte-enriched nuclear (HEN) factors, and cleaved by a furin-like protease that releases the two mature molecules. Bikunin is a Kunitz-type serine protease inhibitor, found in vertebrate serum and urine, modified by a chondroitin sulfate (CS) chain. The structures of these toxins are similar to that of Kunitz-type proteinase inhibitors such as BPTI (bovine pancreatic trypsin inhibitor), showing an alpha/beta fold with irregular secondary structure stabilized by three disulfide bonds. Bikunin contains two Kunitz domains; this model represents the first repeat.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 2101189867 255 AVCSQEAMTGPCRAVMPRWYFDMYKKKCIRFIYGGCGGNRNNFESEEYCMAVCK 308
Cdd:cd22596     1 DSCKLPPDAGPCFGMIQRYFYNSSSMACQTFNYGGCLGNQNNFVTEKECLQTCR 54

juxtamembrane and transmembrane (JMTM) domain found in the amyloid-beta precursor protein (APP) family; The amyloid-beta precursor protein (APP) family includes amyloid-like proteins APLP-1 and APLP-2. APP (also called ABPP, APPI, Alzheimer disease (AD) amyloid protein, amyloid precursor protein, amyloid-beta A4 protein, cerebral vascular amyloid peptide (CVAP), PreA4, or protease nexin-II (PN-II)) functions as a cell surface receptor and performs physiological functions on the surface of neurons relevant to neurite growth, neuronal adhesion and axonogenesis. Amyloid-beta peptides are lipophilic metal chelators with metal-reducing activity; they bind transient metals such as copper, zinc and iron. APLP-1, also called APLP, may play a role in postsynaptic function. It couples to JIP signal transduction through C-terminal binding. APLP-1 may interact with cellular G-protein signaling pathways. It can regulate neurite outgrowth through binding to components of the extracellular matrix such as heparin and collagen I. APLP-2 (also called amyloid protein homolog (APPH), or CDEI box-binding protein (CDEBP)) may play a role in the regulation of hemostasis. Its soluble form may have inhibitory properties towards coagulation factors. APLP-2 may bind to the DNA 5'-GTCACATG-3'(CDEI box). It inhibits trypsin, chymotrypsin, plasmin, factor XIA, and plasma and glandular kallikrein. This model corresponds to juxtamembrane and transmembrane (JMTM) domain of APP, which consists of the intact transmembrane (TM) domain with adjacent N-terminal juxtamembrane (JM) region. More than half of all familial APP mutations of Alzheimer's disease are seen in its JMTM domain region.

                          10        20        30
                  ....*....|....*....|....*....|....*....
gi 2101189867 635 NSLRDDFS-FSSSALIGLLVIAVAIATVIVISLVMLRKR 672
Cdd:cd21699     3 VFLAEDSSnSSFGAVIGLAVGGVAVAIVIVVAVVMLRRR 41

juxtamembrane and transmembrane (JMTM) domain found in amyloid-beta precursor protein (APP) and similar proteins; Amyloid-beta precursor protein (APP), also called APPI, ABPP, Alzheimer disease amyloid protein, amyloid precursor protein, amyloid-beta A4 protein, cerebral vascular amyloid peptide (CVAP), PreA4, or protease nexin-II (PN-II), functions as a cell surface receptor and performs physiological functions on the surface of neurons relevant to neurite growth, neuronal adhesion and axonogenesis. Amyloid-beta peptides are lipophilic metal chelators with metal-reducing activity; they bind transient metals such as copper, zinc and iron. This model corresponds to juxtamembrane and transmembrane (JMTM) domain of APP, which consists of the intact transmembrane (TM) domain with adjacent N-terminal juxtamembrane (JM) region. More than half of all familial APP mutations of Alzheimer's disease are seen in its JMTM domain region.

                          10        20        30
                  ....*....|....*....|....*....|....
gi 2101189867 639 DDFSFSSSALIGLLVIAVAIATVIVISLVMLRKR 672
Cdd:cd21707     7 EDVGSNKGAIIGLMVGGVVIATVIVITLVMLKKK 40

Chromosome segregation ATPase Smc [Cell cycle control, cell division, chromosome partitioning];

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 336 RFQKAKEQLEVRHHN----RMDRVKKEWEEAERQAknlpkAERQTLTQRFQAMVKSLEKEAASEKQQLVETHLaRVEAML 411
Cdd:COG1196   214 RYRELKEELKELEAEllllKLRELEAELEELEAEL-----EELEAELEELEAELAELEAELEELRLELEELEL-ELEEAQ 287

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 412 DDRRRIALEnyLVALQTDpprpHRILQALKRYIRAENKDRLHTIRHYQHVLAVDPEKAAQMKSQVM---THLHVIEERMN 488
Cdd:COG1196   288 AEEYELLAE--LARLEQD----IARLEERRRELEERLEELEEELAELEEELEELEEELEELEEELEeaeEELEEAEAELA 361

                         170       180       190
                  ....*....|....*....|....*....|...
gi 2101189867 489 QSLSLLYKVAYVAEEIQSEIDELLQEQRADMDQ 521
Cdd:COG1196   362 EAEEALLEAEAELAEAEEELEELAEELLEALRA 394

Lipopolysaccharide biosynthesis regulator YciM/LapB, contains six TPR domains and a C-terminal metal-binding domain [Cell wall/membrane/envelope biogenesis];

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 354 RVKKEWEEAERQAKNLPKAERQTLTQRFQ----AMVKSLEKEAASEKQQLVETHLARVEAmLDDRRRI---------ALE 420
Cdd:COG2956    53 RRRGEYDRAIRIHQKLLERDPDRAEALLElaqdYLKAGLLDRAEELLEKLLELDPDDAEA-LRLLAEIyeqegdwekAIE 131

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2101189867 421 NYLVALQTDPPRPHRILQALKRYIRAENKDRlhTIRHYQHVLAVDPEKA------------AQMKSQVMTHLHVIEERMN 488
Cdd:COG2956   132 VLERLLKLGPENAHAYCELAELYLEQGDYDE--AIEALEKALKLDPDCArallllaelyleQGDYEEAIAALERALEQDP 209

                         170       180
                  ....*....|....*....|....*....
gi 2101189867 489 QSLSLLYKVAYVAEEiQSEIDELLQEQRA 517
Cdd:COG2956   210 DYLPALPRLAELYEK-LGDPEEALELLRK 237