ID   CYB5_PHATC              Reviewed;         133 AA.
AC   B7GCG7;
DT   10-APR-2019, integrated into UniProtKB/Swiss-Prot.
DT   10-FEB-2009, sequence version 1.
DT   03-AUG-2022, entry version 67.
DE   RecName: Full=Cytochrome b5 {ECO:0000303|PubMed:30478288};
GN   ORFNames=PHATRDRAFT_30770;
OS   Phaeodactylum tricornutum (strain CCAP 1055/1).
OC   Eukaryota; Sar; Stramenopiles; Ochrophyta; Bacillariophyta;
OC   Bacillariophyceae; Bacillariophycidae; Naviculales; Phaeodactylaceae;
OC   Phaeodactylum.
OX   NCBI_TaxID=556484;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], INTERACTION WITH PHATRDRAFT_45494, FUNCTION,
RP   AND SUBCELLULAR LOCATION.
RC   STRAIN=CCAP 1055/1;
RX   PubMed=30478288; DOI=10.1038/s41564-018-0305-5;
RA   Pollier J., Vancaester E., Kuzhiumparambil U., Vickers C.E., Vandepoele K.,
RA   Goossens A., Fabris M.;
RT   "A widespread alternative squalene epoxidase participates in eukaryote
RT   steroid biosynthesis.";
RL   Nat. Microbiol. 4:226-233(2019).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=CCAP 1055/1;
RX   PubMed=18923393; DOI=10.1038/nature07410;
RA   Bowler C., Allen A.E., Badger J.H., Grimwood J., Jabbari K., Kuo A.,
RA   Maheswari U., Martens C., Maumus F., Otillar R.P., Rayko E., Salamov A.,
RA   Vandepoele K., Beszteri B., Gruber A., Heijde M., Katinka M., Mock T.,
RA   Valentin K., Verret F., Berges J.A., Brownlee C., Cadoret J.P.,
RA   Chiovitti A., Choi C.J., Coesel S., De Martino A., Detter J.C., Durkin C.,
RA   Falciatore A., Fournet J., Haruta M., Huysman M.J., Jenkins B.D.,
RA   Jiroutova K., Jorgensen R.E., Joubert Y., Kaplan A., Kroger N., Kroth P.G.,
RA   La Roche J., Lindquist E., Lommer M., Martin-Jezequel V., Lopez P.J.,
RA   Lucas S., Mangogna M., McGinnis K., Medlin L.K., Montsant A.,
RA   Oudot-Le Secq M.P., Napoli C., Obornik M., Parker M.S., Petit J.L.,
RA   Porcel B.M., Poulsen N., Robison M., Rychlewski L., Rynearson T.A.,
RA   Schmutz J., Shapiro H., Siaut M., Stanley M., Sussman M.R., Taylor A.R.,
RA   Vardi A., von Dassow P., Vyverman W., Willis A., Wyrwicz L.S.,
RA   Rokhsar D.S., Weissenbach J., Armbrust E.V., Green B.R., Van de Peer Y.,
RA   Grigoriev I.V.;
RT   "The Phaeodactylum genome reveals the evolutionary history of diatom
RT   genomes.";
RL   Nature 456:239-244(2008).
CC   -!- FUNCTION: Hemoprotein that functions as an electron carrier for
CC       membrane bound monooxygenases involved in sterol biosynthesis.
CC       {ECO:0000305|PubMed:30478288}.
CC   -!- SUBUNIT: Interacts with alternative squalene epoxidase
CC       PHATRDRAFT_45494. {ECO:0000269|PubMed:30478288}.
CC   -!- SUBCELLULAR LOCATION: Endoplasmic reticulum membrane
CC       {ECO:0000305|PubMed:30478288}; Single-pass membrane protein
CC       {ECO:0000255}.
CC   -!- SIMILARITY: Belongs to the cytochrome b5 family. {ECO:0000305}.
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DR   EMBL; MH422132; AYI99265.1; -; mRNA.
DR   EMBL; CM000627; EEC43865.1; -; Genomic_DNA.
DR   RefSeq; XP_002184806.1; XM_002184770.1.
DR   AlphaFoldDB; B7GCG7; -.
DR   SMR; B7GCG7; -.
DR   STRING; 556484.B7GCG7; -.
DR   PRIDE; B7GCG7; -.
DR   EnsemblProtists; Phatr3_J30770.t1; Phatr3_J30770.p1; Phatr3_J30770.
DR   GeneID; 7198555; -.
DR   KEGG; pti:PHATRDRAFT_30770; -.
DR   eggNOG; KOG0537; Eukaryota.
DR   HOGENOM; CLU_102602_3_0_1; -.
DR   InParanoid; B7GCG7; -.
DR   OMA; STHNTRD; -.
DR   OrthoDB; 1566561at2759; -.
DR   Proteomes; UP000000759; Chromosome 25.
DR   GO; GO:0005789; C:endoplasmic reticulum membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0020037; F:heme binding; IEA:InterPro.
DR   GO; GO:0046872; F:metal ion binding; 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; IPR018506; Cyt_B5_heme-BS.
DR   Pfam; PF00173; Cyt-b5; 1.
DR   PRINTS; PR00363; CYTOCHROMEB5.
DR   SMART; SM01117; Cyt-b5; 1.
DR   SUPFAM; SSF55856; SSF55856; 1.
DR   PROSITE; PS00191; CYTOCHROME_B5_1; 1.
DR   PROSITE; PS50255; CYTOCHROME_B5_2; 1.
PE   1: Evidence at protein level;
KW   Electron transport; Endoplasmic reticulum; Heme; Iron; Membrane;
KW   Metal-binding; Reference proteome; Transmembrane; Transmembrane helix;
KW   Transport.
FT   CHAIN           1..133
FT                   /note="Cytochrome b5"
FT                   /id="PRO_0000446441"
FT   TRANSMEM        108..128
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   DOMAIN          4..86
FT                   /note="Cytochrome b5 heme-binding"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00279"
FT   BINDING         45
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         69
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   133 AA;  14590 MW;  A3F73A3F13A09860 CRC64;
     MSAEKEYILD EISQHTTTES CWLIIGNASN GGPKVYDVTK YLDDHPGGAE VMLDVAGQDA
     DEFFEDIGHS KEARAELKNY LVGNFKIDAA TLAKMKADAE AKAQQKNSGT GIMLIVLMAL
     FAIAYGYYQT QMK