fatty acid desaturase removes two hydrogen atoms from a fatty acid, creating a carbon/carbon double bond; similar to Arabidopsis thaliana delta(12) fatty acid desaturase and related proteins
The Delta12 Fatty Acid Desaturase (Delta12-FADS)-like CD includes the integral-membrane ...
52-334
9.75e-77
The Delta12 Fatty Acid Desaturase (Delta12-FADS)-like CD includes the integral-membrane enzymes, delta-12 acyl-lipid desaturases, oleate 12-hydroxylases, omega3 and omega6 fatty acid desaturases, and other related proteins, found in a wide range of organisms including higher plants, green algae, diatoms, nematodes, fungi, and bacteria. The expression of these proteins appears to be temperature dependent: decreases in temperature result in increased levels of fatty acid desaturation within membrane lipids subsequently altering cell membrane fluidity. An important enzyme for the production of polyunsaturates in plants is the oleate delta-12 desaturase (Arabidopsis FAD2) of the endoplasmic reticulum. This enzyme accepts l-acyl-2-oleoyl-sn-glycero-3-phosphocholine as substrate and requires NADH:cytochrome b oxidoreductase, cytochrome b, and oxygen for activity. FAD2 converts oleate(18:1) to linoleate (18:2) and is closely related to oleate 12-hydroxylase which catalyzes the hydroxylation of oleate to ricinoleate. Plastid-bound desaturases (Arabidopsis delta-12 desaturase (FAD6), omega-3 desaturase (FAD8), omega-6 desaturase (FAD6)), as well as, the cyanobacterial thylakoid-bound FADSs require oxygen, ferredoxin, and ferredoxin oxidoreductase for activity. As in higher plants, the cyanobacteria delta-12 (DesA) and omega-3 (DesB) FADSs desaturate oleate (18:1) to linoleate (18:2) and linoleate (18:2) to linolenate (18:3), respectively. Omega-3 (DesB/FAD8) and omega-6 (DesD/FAD6) desaturases catalyze reactions that introduce a double bond between carbons three and four, and carbons six and seven, respectively, from the methyl end of fatty acids. As with other members of this superfamily, this domain family has extensive hydrophobic regions that would be capable of spanning the membrane bilayer at least twice. Comparison of sequences also reveals the existence of three regions of conserved histidine cluster motifs that contain eight histidine residues: HXXXH, HXX(X)HH, and HXXHH. These histidine residues are reported to be catalytically essential and proposed to be the ligands for the iron atoms contained within the homologue, stearoyl CoA desaturase. Mutation of any one of four of these histidines in the Synechocystis delta-12 acyl-lipid desaturase resulted in complete inactivity.
Pssm-ID: 239584 [Multi-domain] Cd Length: 222 Bit Score: 236.74 E-value: 9.75e-77
Fatty acid desaturase; Fatty acid desaturases are enzymes that catalyze the insertion of a ...
89-349
1.24e-21
Fatty acid desaturase; Fatty acid desaturases are enzymes that catalyze the insertion of a double bond at the delta position of fatty acids. There seem to be two distinct families of fatty acid desaturases which do not seem to be evolutionary related: Family 1 composed of Stearoyl-CoA desaturases (SCD) and Family 2 composed of Bacterial fatty acid desaturases, Plant stearoyl-acyl-carrier-protein desaturase and Cyanobacterial DesA. Members of this entry are ER integral membrane proteins that share the same mushroom-shaped fold consisting of four transmembrane helices (TM1-TM4) which anchor them to the membrane, capped by a cytosolic domain containing a unique 9-10 histidine- coordinating di metal (di-iron) catalytic centre. The structure of mouse stearoyl-CoA desaturase (SDC) revealed that TM2 and TM4 are longer than TM1 and TM3 and protrude into the cytosolic domain, providing three of the nine histidine residues that coordinate the two metal ions, while the other histidine residues are provided by the soluble domain in this enzyme.
Pssm-ID: 425713 [Multi-domain] Cd Length: 252 Bit Score: 93.18 E-value: 1.24e-21
The Delta12 Fatty Acid Desaturase (Delta12-FADS)-like CD includes the integral-membrane ...
52-334
9.75e-77
The Delta12 Fatty Acid Desaturase (Delta12-FADS)-like CD includes the integral-membrane enzymes, delta-12 acyl-lipid desaturases, oleate 12-hydroxylases, omega3 and omega6 fatty acid desaturases, and other related proteins, found in a wide range of organisms including higher plants, green algae, diatoms, nematodes, fungi, and bacteria. The expression of these proteins appears to be temperature dependent: decreases in temperature result in increased levels of fatty acid desaturation within membrane lipids subsequently altering cell membrane fluidity. An important enzyme for the production of polyunsaturates in plants is the oleate delta-12 desaturase (Arabidopsis FAD2) of the endoplasmic reticulum. This enzyme accepts l-acyl-2-oleoyl-sn-glycero-3-phosphocholine as substrate and requires NADH:cytochrome b oxidoreductase, cytochrome b, and oxygen for activity. FAD2 converts oleate(18:1) to linoleate (18:2) and is closely related to oleate 12-hydroxylase which catalyzes the hydroxylation of oleate to ricinoleate. Plastid-bound desaturases (Arabidopsis delta-12 desaturase (FAD6), omega-3 desaturase (FAD8), omega-6 desaturase (FAD6)), as well as, the cyanobacterial thylakoid-bound FADSs require oxygen, ferredoxin, and ferredoxin oxidoreductase for activity. As in higher plants, the cyanobacteria delta-12 (DesA) and omega-3 (DesB) FADSs desaturate oleate (18:1) to linoleate (18:2) and linoleate (18:2) to linolenate (18:3), respectively. Omega-3 (DesB/FAD8) and omega-6 (DesD/FAD6) desaturases catalyze reactions that introduce a double bond between carbons three and four, and carbons six and seven, respectively, from the methyl end of fatty acids. As with other members of this superfamily, this domain family has extensive hydrophobic regions that would be capable of spanning the membrane bilayer at least twice. Comparison of sequences also reveals the existence of three regions of conserved histidine cluster motifs that contain eight histidine residues: HXXXH, HXX(X)HH, and HXXHH. These histidine residues are reported to be catalytically essential and proposed to be the ligands for the iron atoms contained within the homologue, stearoyl CoA desaturase. Mutation of any one of four of these histidines in the Synechocystis delta-12 acyl-lipid desaturase resulted in complete inactivity.
Pssm-ID: 239584 [Multi-domain] Cd Length: 222 Bit Score: 236.74 E-value: 9.75e-77
Fatty acid desaturase; Fatty acid desaturases are enzymes that catalyze the insertion of a ...
89-349
1.24e-21
Fatty acid desaturase; Fatty acid desaturases are enzymes that catalyze the insertion of a double bond at the delta position of fatty acids. There seem to be two distinct families of fatty acid desaturases which do not seem to be evolutionary related: Family 1 composed of Stearoyl-CoA desaturases (SCD) and Family 2 composed of Bacterial fatty acid desaturases, Plant stearoyl-acyl-carrier-protein desaturase and Cyanobacterial DesA. Members of this entry are ER integral membrane proteins that share the same mushroom-shaped fold consisting of four transmembrane helices (TM1-TM4) which anchor them to the membrane, capped by a cytosolic domain containing a unique 9-10 histidine- coordinating di metal (di-iron) catalytic centre. The structure of mouse stearoyl-CoA desaturase (SDC) revealed that TM2 and TM4 are longer than TM1 and TM3 and protrude into the cytosolic domain, providing three of the nine histidine residues that coordinate the two metal ions, while the other histidine residues are provided by the soluble domain in this enzyme.
Pssm-ID: 425713 [Multi-domain] Cd Length: 252 Bit Score: 93.18 E-value: 1.24e-21
The membrane fatty acid desaturase (Membrane_FADS)-like CD includes membrane FADSs, alkane ...
88-195
1.25e-16
The membrane fatty acid desaturase (Membrane_FADS)-like CD includes membrane FADSs, alkane hydroxylases, beta carotene ketolases (CrtW-like), hydroxylases (CrtR-like), and other related proteins. They are present in all groups of organisms with the exception of archaea. Membrane FADSs are non-heme, iron-containing, oxygen-dependent enzymes involved in regioselective introduction of double bonds in fatty acyl aliphatic chains. They play an important role in the maintenance of the proper structure and functioning of biological membranes. Alkane hydroxylases are bacterial, integral-membrane di-iron enzymes that share a requirement for iron and oxygen for activity similar to that of membrane FADSs, and are involved in the initial oxidation of inactivated alkanes. Beta-carotene ketolase and beta-carotene hydroxylase are carotenoid biosynthetic enzymes for astaxanthin and zeaxanthin, respectively. This superfamily domain has extensive hydrophobic regions that would be capable of spanning the membrane bilayer at least twice. Comparison of these sequences also reveals three regions of conserved histidine cluster motifs that contain eight histidine residues: HXXX(X)H, HXX(X)HH, and HXXHH (an additional conserved histidine residue is seen between clusters 2 and 3). Spectroscopic and genetic evidence point to a nitrogen-rich coordination environment located in the cytoplasm with as many as eight histidines coordinating the two iron ions and a carboxylate residue bridging the two metals in the Pseudomonas oleovorans alkane hydroxylase (AlkB). In addition, the eight histidine residues are reported to be catalytically essential and proposed to be the ligands for the iron atoms contained within the rat stearoyl CoA delta-9 desaturase.
Pssm-ID: 238511 [Multi-domain] Cd Length: 122 Bit Score: 75.58 E-value: 1.25e-16
This CD includes the putative hydrocarbon oxygenase, MocD, a bacterial rhizopine ...
88-335
9.57e-13
This CD includes the putative hydrocarbon oxygenase, MocD, a bacterial rhizopine (3-O-methyl-scyllo-inosamine, 3-O-MSI) oxygenase, and other related proteins. It has been proposed that MocD, MocE (Rieske-like ferredoxin), and MocF (ferredoxin reductase) under the regulation of MocR, act in concert to form a ferredoxin oxygenase system that demethylates 3-O-MSI to form scyllo-inosamine. This domain family appears to be structurally related to the membrane fatty acid desaturases and the alkane hydroxylases. They all share in common extensive hydrophobic regions that would be capable of spanning the membrane bilayer at least twice. Comparison of sequences also reveals the existence of three regions of conserved histidine cluster motifs that contain eight histidine residues: HXXXH, HXXHH, and HXXHH. These histidine residues are reported to be catalytically essential and proposed to be the ligands for the iron atoms contained within homologs, stearoyl CoA desaturase and alkane hydroxylase.
Pssm-ID: 239588 [Multi-domain] Cd Length: 285 Bit Score: 68.17 E-value: 9.57e-13
The Delta6 Fatty Acid Desaturase (Delta6-FADS)-like CD includes the integral-membrane enzymes: ...
108-333
7.26e-12
The Delta6 Fatty Acid Desaturase (Delta6-FADS)-like CD includes the integral-membrane enzymes: delta-4, delta-5, delta-6, delta-8, delta-8-sphingolipid, and delta-11 desaturases found in vertebrates, higher plants, fungi, and bacteria. These desaturases are required for the synthesis of highly unsaturated fatty acids (HUFAs), which are mainly esterified into phospholipids and contribute to maintaining membrane fluidity. While HUFAs may be required for cold tolerance in bacteria, plants and fish, the primary role of HUFAs in mammals is cell signaling. These enzymes are described as front-end desaturases because they introduce a double bond between the pre-exiting double bond and the carboxyl (front) end of the fatty acid. Various substrates are involved, with both acyl-coenzyme A (CoA) and acyl-lipid desaturases present in this CD. Acyl-lipid desaturases are localized in the membranes of cyanobacterial thylakoid, plant endoplasmic reticulum (ER), and plastid; and acyl-CoA desaturases are present in ER membrane. ER-bound plant acyl-lipid desaturases and acyl-CoA desaturases require cytochrome b5 as an electron donor. Most of the eukaryotic desaturase domains have an adjacent N-terminal cytochrome b5-like domain. This domain family has extensive hydrophobic regions that would be capable of spanning the membrane bilayer at least twice. Comparison of sequences also reveals the existence of three regions of conserved histidine cluster motifs that contain the residues: HXXXH, HXX(X)HH, and Q/HXXHH. These histidine residues are reported to be catalytically essential and proposed to be the ligands for the iron atoms contained within the homolog, stearoyl CoA desaturase.
Pssm-ID: 239583 [Multi-domain] Cd Length: 204 Bit Score: 64.20 E-value: 7.26e-12
Domain of unknown function (DUF3474); This presumed domain is functionally uncharacterized. ...
7-67
3.32e-06
Domain of unknown function (DUF3474); This presumed domain is functionally uncharacterized. This domain is found in bacteria and eukaryotes. This domain is typically between 126 to 140 amino acids in length. This domain is found associated with pfam00487.
Pssm-ID: 403244 Cd Length: 127 Bit Score: 45.88 E-value: 3.32e-06
Database: CDSEARCH/cdd Low complexity filter: no Composition Based Adjustment: yes E-value threshold: 0.01
References:
Wang J et al. (2023), "The conserved domain database in 2023", Nucleic Acids Res.51(D)384-8.
Lu S et al. (2020), "The conserved domain database in 2020", Nucleic Acids Res.48(D)265-8.
Marchler-Bauer A et al. (2017), "CDD/SPARCLE: functional classification of proteins via subfamily domain architectures.", Nucleic Acids Res.45(D)200-3.
of the residues that compose this conserved feature have been mapped to the query sequence.
Click on the triangle to view details about the feature, including a multiple sequence alignment
of your query sequence and the protein sequences used to curate the domain model,
where hash marks (#) above the aligned sequences show the location of the conserved feature residues.
The thumbnail image, if present, provides an approximate view of the feature's location in 3 dimensions.
Click on the triangle for interactive 3D structure viewing options.
Functional characterization of the conserved domain architecture found on the query.
Click here to see more details.
This image shows a graphical summary of conserved domains identified on the query sequence.
The Show Concise/Full Display button at the top of the page can be used to select the desired level of detail: only top scoring hits
(labeled illustration) or all hits
(labeled illustration).
Domains are color coded according to superfamilies
to which they have been assigned. Hits with scores that pass a domain-specific threshold
(specific hits) are drawn in bright colors.
Others (non-specific hits) and
superfamily placeholders are drawn in pastel colors.
if a domain or superfamily has been annotated with functional sites (conserved features),
they are mapped to the query sequence and indicated through sets of triangles
with the same color and shade of the domain or superfamily that provides the annotation. Mouse over the colored bars or triangles to see descriptions of the domains and features.
click on the bars or triangles to view your query sequence embedded in a multiple sequence alignment of the proteins used to develop the corresponding domain model.
The table lists conserved domains identified on the query sequence. Click on the plus sign (+) on the left to display full descriptions, alignments, and scores.
Click on the domain model's accession number to view the multiple sequence alignment of the proteins used to develop the corresponding domain model.
To view your query sequence embedded in that multiple sequence alignment, click on the colored bars in the Graphical Summary portion of the search results page,
or click on the triangles, if present, that represent functional sites (conserved features)
mapped to the query sequence.
Concise Display shows only the best scoring domain model, in each hit category listed below except non-specific hits, for each region on the query sequence.
(labeled illustration) Standard Display shows only the best scoring domain model from each source, in each hit category listed below for each region on the query sequence.
(labeled illustration) Full Display shows all domain models, in each hit category below, that meet or exceed the RPS-BLAST threshold for statistical significance.
(labeled illustration) Four types of hits can be shown, as available,
for each region on the query sequence:
specific hits meet or exceed a domain-specific e-value threshold
(illustrated example)
and represent a very high confidence that the query sequence belongs to the same protein family as the sequences use to create the domain model
non-specific hits
meet or exceed the RPS-BLAST threshold for statistical significance (default E-value cutoff of 0.01, or an E-value selected by user via the
advanced search options)
the domain superfamily to which the specific and non-specific hits belong
multi-domain models that were computationally detected and are likely to contain multiple single domains
Retrieve proteins that contain one or more of the domains present in the query sequence, using the Conserved Domain Architecture Retrieval Tool
(CDART).
Modify your query to search against a different database and/or use advanced search options
