SLD1_HELAN
ID SLD1_HELAN Reviewed; 458 AA.
AC Q43469;
DT 05-SEP-2012, integrated into UniProtKB/Swiss-Prot.
DT 01-NOV-1996, sequence version 1.
DT 03-AUG-2022, entry version 98.
DE RecName: Full=Delta(8)-fatty-acid desaturase;
DE EC=1.14.19.29 {ECO:0000269|PubMed:11171153, ECO:0000269|PubMed:12203571, ECO:0000269|PubMed:20575587};
DE AltName: Full=Delta(8)-sphingolipid desaturase;
DE AltName: Full=Sphingolipid 8-(E/Z)-desaturase;
GN Name=sld1;
OS Helianthus annuus (Common sunflower).
OC Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC asterids; campanulids; Asterales; Asteraceae; Asteroideae;
OC Heliantheae alliance; Heliantheae; Helianthus.
OX NCBI_TaxID=4232;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA].
RX PubMed=7588718; DOI=10.1111/j.1432-1033.1995.tb20875.x;
RA Sperling P., Schmidt H., Heinz E.;
RT "A cytochrome-b5-containing fusion protein similar to plant acyl lipid
RT desaturases.";
RL Eur. J. Biochem. 232:798-805(1995).
RN [2]
RP CATALYTIC ACTIVITY, FUNCTION, AND REACTION MECHANISM.
RX PubMed=11171153; DOI=10.1042/bst0280638;
RA Sperling P., Blume A., Zahringer U., Heinz E.;
RT "Further characterization of Delta(8)-sphingolipid desaturases from higher
RT plants.";
RL Biochem. Soc. Trans. 28:638-641(2000).
RN [3]
RP CATALYTIC ACTIVITY, AND FUNCTION.
RX PubMed=12203571;
RX DOI=10.1002/1521-3773(20020703)41:13<2298::aid-anie2298>3.0.co;2-g;
RA Beckmann C., Rattke J., Oldham N.J., Sperling P., Heinz E., Boland W.;
RT "Characterization of a Delta8-sphingolipid desaturase from higher plants: a
RT stereochemical and mechanistic study on the origin of E,Z isomers.";
RL Angew. Chem. Int. Ed. 41:2298-2300(2002).
RN [4]
RP CATALYTIC ACTIVITY.
RX PubMed=20575587; DOI=10.1021/jo100542q;
RA Habel A., Sperling P., Bartram S., Heinz E., Boland W.;
RT "Conformational studies on the Delta8(E,Z)-sphingolipid desaturase from
RT Helianthus annuus with chiral fluoropalmitic acids as mechanistic probes.";
RL J. Org. Chem. 75:4975-4982(2010).
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. This structural
CC modification contributes to the quantitative partitioning of ceramides
CC between the two major sphingolipid classes, glucosylceramides and
CC 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:11171153, ECO:0000269|PubMed:12203571}.
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:11171153, ECO:0000269|PubMed:12203571,
CC ECO:0000269|PubMed:20575587};
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:11171153, ECO:0000269|PubMed:12203571,
CC ECO:0000269|PubMed:20575587};
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 -!- 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; X87143; CAA60621.1; -; mRNA.
DR PIR; S68358; S68358.
DR AlphaFoldDB; Q43469; -.
DR SMR; Q43469; -.
DR EnsemblPlants; mRNA:HanXRQr2_Chr16g0766151; mRNA:HanXRQr2_Chr16g0766151; HanXRQr2_Chr16g0766151.
DR Gramene; mRNA:HanXRQr2_Chr16g0766151; mRNA:HanXRQr2_Chr16g0766151; HanXRQr2_Chr16g0766151.
DR OMA; YFFLVAP; -.
DR OrthoDB; 1060606at2759; -.
DR PhylomeDB; Q43469; -.
DR BRENDA; 1.14.19.29; 2597.
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..458
FT /note="Delta(8)-fatty-acid desaturase"
FT /id="PRO_0000418893"
FT TRANSMEM 122..142
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 147..167
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 185..205
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 264..284
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 293..313
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 320..340
FT /note="Helical"
FT /evidence="ECO:0000255"
FT DOMAIN 16..100
FT /note="Cytochrome b5 heme-binding"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00279"
FT MOTIF 169..173
FT /note="Histidine box-1"
FT /evidence="ECO:0000305"
FT MOTIF 206..210
FT /note="Histidine box-2"
FT /evidence="ECO:0000305"
FT MOTIF 383..387
FT /note="Histidine box-3"
FT /evidence="ECO:0000305"
FT BINDING 51
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 74
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 458 AA; 52231 MW; D182287AB0E99245 CRC64;
MVSPSIEVLN SIADGKKYIT SKELKKHNNP NDLWISILGK VYNVTEWAKE HPGGDAPLIN
LAGQDVTDAF IAFHPGTAWK HLDKLFTGYH LKDYQVSDIS RDYRKLASEF AKAGMFEKKG
HGVIYSLCFV SLLLSACVYG VLYSGSFWIH MLSGAILGLA WMQIAYLGHD AGHYQMMATR
GWNKFAGIFI GNCITGISIA WWKWTHNAHH IACNSLDYDP DLQHLPMLAV SSKLFNSITS
VFYGRQLTFD PLARFFVSYQ HYLYYPIMCV ARVNLYLQTI LLLISKRKIP DRGLNILGTL
IFWTWFPLLV SRLPNWPERV AFVLVSFCVT GIQHIQFTLN HFSGDVYVGP PKGDNWFEKQ
TRGTIDIACS SWMDWFFGGL QFQLEHHLFP RLPRCHLRSI SPICRELCKK YNLPYVSLSF
YDANVTTLKT LRTAALQARD LTNPAPQNLA WEAFNTHG
