SLD1_BOROF
ID SLD1_BOROF Reviewed; 446 AA.
AC Q9FR82;
DT 05-SEP-2012, integrated into UniProtKB/Swiss-Prot.
DT 01-MAR-2001, sequence version 1.
DT 03-AUG-2022, entry version 87.
DE RecName: Full=Delta(8)-fatty-acid desaturase;
DE EC=1.14.19.29 {ECO:0000269|PubMed:11368168};
DE AltName: Full=Delta(8)-sphingolipid desaturase;
DE AltName: Full=Sphingolipid 8-(E/Z)-desaturase;
GN Name=sld1;
OS Borago officinalis (Bourrache) (Borage).
OC Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC asterids; lamiids; Boraginales; Boraginaceae; Boraginoideae; Boragineae;
OC Boragininae; Borago.
OX NCBI_TaxID=13363;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA], CATALYTIC ACTIVITY, FUNCTION, AND TISSUE
RP SPECIFICITY.
RX PubMed=11368168; DOI=10.1006/abbi.2001.2308;
RA Sperling P., Libisch B., Zahringer U., Napier J.A., Heinz E.;
RT "Functional identification of a delta8-sphingolipid desaturase from Borago
RT officinalis.";
RL Arch. Biochem. Biophys. 388:293-298(2001).
RN [2]
RP FUNCTION.
RX PubMed=11162428; DOI=10.1006/bbrc.2000.4023;
RA Libisch B., Michaelson L.V., Lewis M.J., Shewry P.R., Napier J.A.;
RT "Chimeras of Delta6-fatty acid and Delta8-sphingolipid desaturases.";
RL Biochem. Biophys. Res. Commun. 279:779-785(2000).
CC -!- FUNCTION: Plays a major role as delta(8)-fatty-acid desaturase which
CC introduces a double bond at the 8-position in the long-chain base (LCB)
CC of ceramides with or without a hydroxy group at the 4-position. The
CC enzyme produces both the 8E and 8Z isomers (in a 4:1 ratio). This
CC structural modification contributes to the quantitative partitioning of
CC ceramides between the two major sphingolipid classes, glucosylceramides
CC and glycosylinositolphosphoryl ceramides. Sphingolipids are important
CC membrane components involved in environmental stress responses, such as
CC resistance to chilling, and act as cell signaling molecules.
CC {ECO:0000269|PubMed:11162428, ECO:0000269|PubMed:11368168}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=an N-acyl-(4R)-4-hydroxysphinganine + 2 Fe(II)-[cytochrome b5]
CC + 2 H(+) + O2 = a (4R,8E)-4-hydroxysphingenine ceramide + 2 Fe(III)-
CC [cytochrome b5] + 2 H2O; Xref=Rhea:RHEA:46268, Rhea:RHEA-COMP:10438,
CC Rhea:RHEA-COMP:10439, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378,
CC ChEBI:CHEBI:15379, ChEBI:CHEBI:29033, ChEBI:CHEBI:29034,
CC ChEBI:CHEBI:31998, ChEBI:CHEBI:50934; EC=1.14.19.29;
CC Evidence={ECO:0000269|PubMed:11368168};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=an N-acyl-(4R)-4-hydroxysphinganine + 2 Fe(II)-[cytochrome b5]
CC + 2 H(+) + O2 = (4R,8Z)-4-hydroxysphing-8-enine ceramide + 2 Fe(III)-
CC [cytochrome b5] + 2 H2O; Xref=Rhea:RHEA:46272, Rhea:RHEA-COMP:10438,
CC Rhea:RHEA-COMP:10439, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378,
CC ChEBI:CHEBI:15379, ChEBI:CHEBI:29033, ChEBI:CHEBI:29034,
CC ChEBI:CHEBI:31998, ChEBI:CHEBI:85951; EC=1.14.19.29;
CC Evidence={ECO:0000269|PubMed:11368168};
CC -!- COFACTOR:
CC Name=Fe cation; Xref=ChEBI:CHEBI:24875; Evidence={ECO:0000250};
CC -!- SUBCELLULAR LOCATION: Membrane {ECO:0000305}; Multi-pass membrane
CC protein {ECO:0000305}.
CC -!- TISSUE SPECIFICITY: Expressed only in young leaves.
CC {ECO:0000269|PubMed:11368168}.
CC -!- DOMAIN: The histidine box domains may contain the active site and/or be
CC involved in metal ion binding. {ECO:0000250}.
CC -!- SIMILARITY: Belongs to the fatty acid desaturase type 1 family.
CC {ECO:0000305}.
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DR EMBL; AF133728; AAG43277.1; -; mRNA.
DR AlphaFoldDB; Q9FR82; -.
DR SMR; Q9FR82; -.
DR BRENDA; 1.14.19.29; 895.
DR BRENDA; 1.14.19.4; 895.
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:0052631; F:sphingolipid delta-8 desaturase activity; IEA:RHEA.
DR GO; GO:0006665; P:sphingolipid metabolic process; IEA:UniProtKB-KW.
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; Heme; Iron; Lipid metabolism; Membrane; Metal-binding;
KW Oxidoreductase; Sphingolipid metabolism; Transmembrane;
KW Transmembrane helix; Transport.
FT CHAIN 1..446
FT /note="Delta(8)-fatty-acid desaturase"
FT /id="PRO_0000418892"
FT TRANSMEM 112..132
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 136..156
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 174..195
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 253..273
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 282..302
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 309..329
FT /note="Helical"
FT /evidence="ECO:0000255"
FT DOMAIN 5..89
FT /note="Cytochrome b5 heme-binding"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00279"
FT MOTIF 158..162
FT /note="Histidine box-1"
FT /evidence="ECO:0000305"
FT MOTIF 195..199
FT /note="Histidine box-2"
FT /evidence="ECO:0000305"
FT MOTIF 372..376
FT /note="Histidine box-3"
FT /evidence="ECO:0000305"
FT BINDING 40
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 446 AA; 50927 MW; EBD579F035A3AF0C CRC64;
MEGTKKYISV GELEKHNQLG DVWISIQGKV YNVTDWIKKH PGGDVPIMNL AGQDATDAFI
AYHPGTAWKN LENLFTGYHL EDYLVSEISK DYRKLASEFS KAGLFEKKGH TVIYCLSFIA
LLLCGCVYGV LCSNSLWVHM LSGAMLGMCF IQAAYLGHDS GHYTMMSSKG YNKFAQVLNG
NCLTGISIAW WKWTHNAHHI ACNSLDYDPD LQHLPVFAVP SSFFKSLTSR FYGRELTFDG
LSRFLVSYQH FTIYLVMIFG RINLYVQTFL LLFSTRKVPD RALNIIGILV YWTWFPYLVS
CLPNWNERVL FVLTCFSVTA LQHIQFTLNH FAADVYVGPP TGTNWFEKQA AGTIDISCSS
WMDWFFGGLQ FQLEHHLFPR MPRCQLRNIS PIVQDYCKKH NLPYRSLSFF DANVATIKTL
RTAALQARDL TVVPQNLLWE AFNTHG
