D4FAD_THRSP
ID D4FAD_THRSP Reviewed; 519 AA.
AC Q8S3C0;
DT 11-NOV-2015, integrated into UniProtKB/Swiss-Prot.
DT 01-JUN-2002, sequence version 1.
DT 03-AUG-2022, entry version 74.
DE RecName: Full=Acyl-lipid (7-3)-desaturase {ECO:0000305};
DE EC=1.14.19.31 {ECO:0000269|PubMed:11397798};
DE AltName: Full=Acyl-lipid 4-desaturase {ECO:0000305};
DE AltName: Full=Delta-4 fatty acid desaturase {ECO:0000303|PubMed:11397798};
GN Name=Fad4 {ECO:0000303|PubMed:11397798};
OS Thraustochytrium sp.
OC Eukaryota; Sar; Stramenopiles; Bigyra; Labyrinthulomycetes;
OC Thraustochytrida; Thraustochytriaceae; Thraustochytrium;
OC unclassified Thraustochytrium.
OX NCBI_TaxID=145168;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, AND CATALYTIC ACTIVITY.
RC STRAIN=ATCC 21685 {ECO:0000312|EMBL:AAM09688.1};
RX PubMed=11397798; DOI=10.1074/jbc.m102971200;
RA Qiu X., Hong H., MacKenzie S.L.;
RT "Identification of a Delta 4 fatty acid desaturase from Thraustochytrium
RT sp. involved in the biosynthesis of docosahexanoic acid by heterologous
RT expression in Saccharomyces cerevisiae and Brassica juncea.";
RL J. Biol. Chem. 276:31561-31566(2001).
CC -!- FUNCTION: Fatty acid desaturase that introduces a cis double bond at
CC the 4-position in 22-carbon polyunsaturated fatty acids that contain a
CC Delta(7) double bond, resulting in the production of delta-4
CC desaturated fatty acid docosahexanoic acid (DHA)
CC (22:6(4,7,10,13,16,19)). {ECO:0000269|PubMed:11397798}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=a (7Z,10Z,13Z,16Z,19Z)-docosapentaenoyl-containing
CC glycerolipid + 2 Fe(II)-[cytochrome b5] + 2 H(+) + O2 = a
CC (4Z,7Z,10Z,13Z,16Z,19Z)-docosahexaenoyl-containing glycerolipid + 2
CC Fe(III)-[cytochrome b5] + 2 H2O; Xref=Rhea:RHEA:46252, Rhea:RHEA-
CC COMP:10438, Rhea:RHEA-COMP:10439, ChEBI:CHEBI:15377,
CC ChEBI:CHEBI:15378, ChEBI:CHEBI:15379, ChEBI:CHEBI:29033,
CC ChEBI:CHEBI:29034, ChEBI:CHEBI:88266, ChEBI:CHEBI:88267;
CC EC=1.14.19.31; Evidence={ECO:0000269|PubMed:11397798};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=a (7Z,10Z,13Z,16Z)-docosatetraenoyl-containing glycerolipid +
CC 2 Fe(II)-[cytochrome b5] + 2 H(+) + O2 = a (4Z,7Z,10Z,13Z,16Z)-
CC docosapentaenoyl-containing glycerolipid + 2 Fe(III)-[cytochrome b5]
CC + 2 H2O; Xref=Rhea:RHEA:46256, Rhea:RHEA-COMP:10438, Rhea:RHEA-
CC COMP:10439, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:15379,
CC ChEBI:CHEBI:29033, ChEBI:CHEBI:29034, ChEBI:CHEBI:88264,
CC ChEBI:CHEBI:88265; EC=1.14.19.31;
CC Evidence={ECO:0000269|PubMed:11397798};
CC -!- COFACTOR:
CC Name=Fe(2+); Xref=ChEBI:CHEBI:29033;
CC Evidence={ECO:0000250|UniProtKB:O00767};
CC -!- SUBCELLULAR LOCATION: Membrane {ECO:0000255}; Multi-pass membrane
CC protein {ECO:0000255}.
CC -!- DOMAIN: The cytochrome b5 heme-binding domain acts as the direct
CC electron donor to the active site of the desaturase, and does not
CC require an external cytochrome. {ECO:0000305}.
CC -!- SIMILARITY: Belongs to the fatty acid desaturase type 1 family.
CC {ECO:0000305}.
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DR EMBL; AF489589; AAM09688.1; -; mRNA.
DR AlphaFoldDB; Q8S3C0; -.
DR SMR; Q8S3C0; -.
DR SwissLipids; SLP:000000466; -.
DR BioCyc; MetaCyc:MON-16978; -.
DR BRENDA; 1.14.19.31; 14019.
DR GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR GO; GO:0016717; F:oxidoreductase activity, acting on paired donors, with oxidation of a pair of donors resulting in the reduction of molecular oxygen to two molecules of water; IDA:UniProtKB.
DR GO; GO:0042759; P:long-chain fatty acid biosynthetic process; IDA:UniProtKB.
DR GO; GO:0006636; P:unsaturated fatty acid biosynthetic process; IDA:UniProtKB.
DR Gene3D; 3.10.120.10; -; 1.
DR InterPro; IPR001199; Cyt_B5-like_heme/steroid-bd.
DR InterPro; IPR036400; Cyt_B5-like_heme/steroid_sf.
DR InterPro; IPR005804; FA_desaturase_dom.
DR InterPro; IPR012171; Fatty_acid_desaturase.
DR PANTHER; PTHR19353; PTHR19353; 1.
DR Pfam; PF00173; Cyt-b5; 1.
DR Pfam; PF00487; FA_desaturase; 1.
DR PIRSF; PIRSF015921; FA_sphinglp_des; 1.
DR SMART; SM01117; Cyt-b5; 1.
DR SUPFAM; SSF55856; SSF55856; 1.
DR PROSITE; PS50255; CYTOCHROME_B5_2; 1.
PE 1: Evidence at protein level;
KW Electron transport; Fatty acid biosynthesis; Fatty acid metabolism; Heme;
KW Iron; Lipid biosynthesis; Lipid metabolism; Membrane; Metal-binding;
KW Oxidoreductase; Transmembrane; Transmembrane helix; Transport.
FT CHAIN 1..519
FT /note="Acyl-lipid (7-3)-desaturase"
FT /id="PRO_0000434754"
FT TRANSMEM 135..155
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 160..180
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 282..302
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 324..344
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 349..369
FT /note="Helical"
FT /evidence="ECO:0000255"
FT DOMAIN 6..81
FT /note="Cytochrome b5 heme-binding"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00279"
FT MOTIF 182..186
FT /note="Histidine box-1"
FT /evidence="ECO:0000305"
FT MOTIF 217..222
FT /note="Histidine box-2"
FT /evidence="ECO:0000305"
FT MOTIF 454..458
FT /note="Histidine box-3"
FT /evidence="ECO:0000305"
FT BINDING 41
FT /ligand="heme"
FT /ligand_id="ChEBI:CHEBI:30413"
FT /ligand_part="Fe"
FT /ligand_part_id="ChEBI:CHEBI:18248"
FT /note="axial binding residue"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00279"
FT BINDING 63
FT /ligand="heme"
FT /ligand_id="ChEBI:CHEBI:30413"
FT /ligand_part="Fe"
FT /ligand_part_id="ChEBI:CHEBI:18248"
FT /note="axial binding residue"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00279"
SQ SEQUENCE 519 AA; 59119 MW; FCB91529744AA453 CRC64;
MTVGYDEEIP FEQVRAHNKP DDAWCAIHGH VYDVTKFASV HPGGDIILLA AGKEATVLYE
TYHVRGVSDA VLRKYRIGKL PDGQGGANEK EKRTLSGLSS ASYYTWNSDF YRVMRERVVA
RLKERGKARR GGYELWIKAF LLLVGFWSSL YWMCTLDPSF GAILAAMSLG VFAAFVGTCI
QHDGNHGAFA QSRWVNKVAG WTLDMIGASG MTWEFQHVLG HHPYTNLIEE ENGLQKVSGK
KMDTKLADQE SDPDVFSTYP MMRLHPWHQK RWYHRFQHIY GPFIFGFMTI NKVVTQDVGV
VLRKRLFQID AECRYASPMY VARFWIMKAL TVLYMVALPC YMQGPWHGLK LFAIAHFTCG
EVLATMFIVN HIIEGVSYAS KDAVKGTMAP PKTMHGVTPM NNTRKEVEAE ASKSGAVVKS
VPLDDWAVVQ CQTSVNWSVG SWFWNHFSGG LNHQIEHHLF PGLSHETYYH IQDVFQSTCA
EYGVPYQHEP SLWTAYWKML EHLRQLGNEE THESWQRAA
