Alpha crystallin domain (ACD) found in Saccharomyces cerevisiae (Sc) small heat shock protein (Hsp)26 and similar proteins. sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. ScHsp26 is temperature-regulated, it switches from an inactive to a chaperone-active form upon elevation in temperature. It associates into large 24-mers storage forms which upon heat shock disassociate into dimers. These dimers initiate the interaction with non-native substrate proteins and re-assemble into large globular assemblies having one monomer of substrate bound per dimer. This group also contains Arabidopsis thaliana (Ath) Hsp15.7, a peroxisomal matrix protein which can complement the morphological phenotype of S. cerevisiae mutants deficient in Hsps26. AthHsp15.7 is minimally expressed under normal conditions and is strongly induced by heat and oxidative stress. Also belonging to this group is wheat HSP16.9 which differs in quaternary structure from the shell-type particles of ScHsp26, it assembles as a dodecameric double disc, with each disc organized as a trimer of dimers.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15218934  47 RVDWKETAEAHVFKADLPGMKKEEVKVEIEDDSVLKISGERHVEKEEKQDTWHRVERSSGGFSRKFRLPENVKMDQVKAS 126
Cdd:cd06472   1 RVDWKETPEAHVFKADVPGVKKEDVKVEVEDGRVLRISGERKKEEEKKGDDWHRVERSSGRFVRRFRLPENADADEVKAF 80

                        90
                ....*....|..
gi 15218934 127 MENGVLTVTVPK 138
Cdd:cd06472  81 LENGVLTVTVPK 92

Alpha crystallin domain (ACD) found in Saccharomyces cerevisiae (Sc) small heat shock protein (Hsp)26 and similar proteins. sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. ScHsp26 is temperature-regulated, it switches from an inactive to a chaperone-active form upon elevation in temperature. It associates into large 24-mers storage forms which upon heat shock disassociate into dimers. These dimers initiate the interaction with non-native substrate proteins and re-assemble into large globular assemblies having one monomer of substrate bound per dimer. This group also contains Arabidopsis thaliana (Ath) Hsp15.7, a peroxisomal matrix protein which can complement the morphological phenotype of S. cerevisiae mutants deficient in Hsps26. AthHsp15.7 is minimally expressed under normal conditions and is strongly induced by heat and oxidative stress. Also belonging to this group is wheat HSP16.9 which differs in quaternary structure from the shell-type particles of ScHsp26, it assembles as a dodecameric double disc, with each disc organized as a trimer of dimers.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15218934  47 RVDWKETAEAHVFKADLPGMKKEEVKVEIEDDSVLKISGERHVEKEEKQDTWHRVERSSGGFSRKFRLPENVKMDQVKAS 126
Cdd:cd06472   1 RVDWKETPEAHVFKADVPGVKKEDVKVEVEDGRVLRISGERKKEEEKKGDDWHRVERSSGRFVRRFRLPENADADEVKAF 80

                        90
                ....*....|..
gi 15218934 127 MENGVLTVTVPK 138
Cdd:cd06472  81 LENGVLTVTVPK 92

Hsp20/alpha crystallin family; Not only do small heat-shock-proteins occur in eukaryotes and prokaryotes but they have also now been shown to occur in cyanobacterial phages as well as their bacterial hosts.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15218934    49 DWKETAEAHVFKADLPGMKKEEVKVEIEDDSVLkISGERhvEKEEKQDTWHRVERSSGGFSRKFRLPENVKMDQVKASME 128
Cdd:pfam00011   1 DIKEDEDAFEVRLDVPGFKPEELKVKVEDNRLL-VKGEH--EEEKEDDHGLRSERSYGSFSRKFTLPENADPDKVKASLK 77

                          90       100
                  ....*....|....*....|....*.
gi 15218934   129 NGVLTVTVPKVETNKKkaqVKSIDIS 154
Cdd:pfam00011  78 DGVLTVTVPKLEPEPK---ERRIQIQ 100

Alpha crystallin domain (ACD) found in Saccharomyces cerevisiae (Sc) small heat shock protein (Hsp)26 and similar proteins. sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. ScHsp26 is temperature-regulated, it switches from an inactive to a chaperone-active form upon elevation in temperature. It associates into large 24-mers storage forms which upon heat shock disassociate into dimers. These dimers initiate the interaction with non-native substrate proteins and re-assemble into large globular assemblies having one monomer of substrate bound per dimer. This group also contains Arabidopsis thaliana (Ath) Hsp15.7, a peroxisomal matrix protein which can complement the morphological phenotype of S. cerevisiae mutants deficient in Hsps26. AthHsp15.7 is minimally expressed under normal conditions and is strongly induced by heat and oxidative stress. Also belonging to this group is wheat HSP16.9 which differs in quaternary structure from the shell-type particles of ScHsp26, it assembles as a dodecameric double disc, with each disc organized as a trimer of dimers.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15218934  47 RVDWKETAEAHVFKADLPGMKKEEVKVEIEDDSVLKISGERHVEKEEKQDTWHRVERSSGGFSRKFRLPENVKMDQVKAS 126
Cdd:cd06472   1 RVDWKETPEAHVFKADVPGVKKEDVKVEVEDGRVLRISGERKKEEEKKGDDWHRVERSSGRFVRRFRLPENADADEVKAF 80

                        90
                ....*....|..
gi 15218934 127 MENGVLTVTVPK 138
Cdd:cd06472  81 LENGVLTVTVPK 92

Alpha-crystallin domain (ACD) of alpha-crystallin-type small(s) heat shock proteins (Hsps). sHsps are small stress induced proteins with monomeric masses between 12 -43 kDa, whose common feature is the Alpha-crystallin domain (ACD). sHsps are generally active as large oligomers consisting of multiple subunits, and are believed to be ATP-independent chaperones that prevent aggregation and are important in refolding in combination with other Hsps.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15218934  49 DWKETAEAHVFKADLPGMKKEEVKVEIEDDsVLKISGERHVEKEEKqDTWHRVERSSGGFSRKFRLPENVKMDQVKASME 128
Cdd:cd06464   1 DVYETDDAYVVEADLPGFKKEDIKVEVEDG-VLTISGEREEEEEEE-ENYLRRERSYGSFSRSFRLPEDVDPDKIKASLE 78

                        90
                ....*....|
gi 15218934 129 NGVLTVTVPK 138
Cdd:cd06464  79 NGVLTITLPK 88

Group of bacterial proteins containing an alpha crystallin domain (ACD) similar to Lactobacillus plantarum (Lp) small heat shock proteins (sHsp) HSP 18.5, HSP 18.55 and HSP 19.3. sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. Transcription of the genes encoding Lp HSP 18.5, 18.55 and 19.3 is regulated by a variety of stresses including heat, cold and ethanol. Early growing L. plantarum cells contain elevated levels of these mRNAs which rapidly fall of as the cells enter stationary phase. Also belonging to this group is Bifidobacterium breve (Bb) HSP20 and Oenococcus oenis (syn. Leuconostoc oenos) (Oo) HSP18. Transcription of the gene encoding BbHSP20 is strongly induced following heat or osmotic shock, and that of the gene encoding OoHSP18 following heat, ethanol or acid shock. OoHSP18 is peripherally associated with the cytoplasmic membrane.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15218934  47 RVDWKETAEAHVFKADLPGMKKEEVKVEIEDDsVLKISGERHVEKEEKQD--TWHRVERSSGGFSRKFRLPeNVKMDQVK 124
Cdd:cd06471   2 KTDIKETDDEYIVEADLPGFKKEDIKLDYKDG-YLTISAKRDESKDEKDKkgNYIRRERYYGSFSRSFYLP-NVDEEEIK 79

                        90
                ....*....|....
gi 15218934 125 ASMENGVLTVTVPK 138
Cdd:cd06471  80 AKYENGVLKITLPK 93

Alpha-crystallin domain (ACD) of metazoan alpha-crystallin-type small(s) heat shock proteins (Hsps). sHsps are small stress induced proteins with monomeric masses between 12 -43 kDa, whose common feature is the Alpha-crystallin domain (ACD). sHsps are generally active as large oligomers consisting of multiple subunits, and are believed to be ATP-independent chaperones that prevent aggregation and are important in refolding in combination with other Hsps.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 15218934  62 DLPGMKKEEVKVEIEDDsVLKISGERhvekEEKQDTWHRVERSsggFSRKFRLPENVKMDQVKASM-ENGVLTVTVPK 138
Cdd:cd06526  14 DVKGFKPEELKVKVSDN-KLVVEGKH----EEREDEHGYVSRE---FTRRYQLPEGVDPDSVTSSLsSDGVLTIEAPK 83

Alpha-crystallin domain found in alphaA-crystallin (HspB4), alphaB-crystallin (HspB5), and the small heat shock protein (sHsp) HspB6, also known as Hsp20. sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. Alpha crystallin, an abundant protein in the mammalian lens, is a large (700 kDa) heteropolymer composed of HspB4 and HspB5, generally in a molar ratio of HspB4:HspB5 of 3:1. Only trace amounts of HspB4 are found in tissues other than the lens. HspB5 on the other hand is also expressed constitutively in other tissues including brain, heart, and type I and type IIa skeletal muscle fibers, and in several cancers including gliomas, renal cell carcinomas, basal-like and metaplastic breast carcinomas, and head and neck cancer. HspB5's functions include effects on the apoptotic pathway and on metastasis. Phosphorylation of HspB5 reduces its oligomerization and anti-apoptotic activities. HspB5 is protective in demyelinating disease such as multiple sclerosis (MS), being a negative regulator of inflammation. In early active MS lesions it is the most abundant gene transcript and an autoantigen, the immune response against it would disrupt its function and worsen inflammation and demyelination. Given as therapy for ongoing demyelinating disease it may counteract this effect. It is an autoantigen in the pathogenesis of various other inflammatory disorders including Lens-associated uveitis (LAU), and Behcet's disease. Mutations in HspB5 have been associated with diseases including dominant cataract and desmin-related myopathy. Mutations in HspB4 have been associated with Autosomal Dominant Congenital Cataract (ADCC). HspB6 (Hsp20) is ubiquitous and is involved in diverse functions including regulation of glucose transport and contraction of smooth muscle, in platelet aggregation, in cardioprotection, and in the prevention of apoptosis. It interacts with the universal scaffolding and adaptor protein 14-3-3, and also with the proapoptotic protein Bax.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 15218934  69 EEVKVEIEDDSVlkisgERHVEKEEKQDTWHRVERSsggFSRKFRLPENVKMDQVKASME-NGVLTVTVPK 138
Cdd:cd06478  21 EELSVKVLGDFV-----EIHGKHEERQDEHGFISRE---FHRRYRLPPGVDPAAITSSLSaDGVLTISGPR 83

Alpha-crystallin domain found in the small heat shock protein (sHsp) alphaA-crystallin (HspB4, 20kDa). sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. Alpha crystallin, an abundant protein in the mammalian lens, is a large (700 kDa) heteropolymer composed of HspB4 and HspB5, generally in a molar ratio of HspB4:HspB5 of 3:1. Only trace amounts of HspB4 are found in tissues other than the lens. HspB5 does not belong to this group. Mutations inHspB4 have been associated with Autosomal Dominant Congenital Cataract (ADCC). The chaperone-like functions of HspB4 are considered important for maintaining lens transparency and preventing cataract.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 15218934  62 DLPGMKKEEVKVEIEDDSVlkisgERHVEKEEKQDTWHRVERSsggFSRKFRLPENVKMDQVKASME-NGVLTVTVPK 138
Cdd:cd06497  17 DVKHFSPEDLTVKVLDDYV-----EIHGKHSERQDDHGYISRE---FHRRYRLPSNVDQSAITCSLSaDGMLTFSGPK 86