ID   MCR1B_VANPO             Reviewed;         306 AA.
AC   A7TM72;
DT   29-APR-2008, integrated into UniProtKB/Swiss-Prot.
DT   02-OCT-2007, sequence version 1.
DT   04-NOV-2026, entry version 78.
DE   RecName: Full=NADH-cytochrome b5 reductase 2-B;
DE            EC=1.6.2.2;
DE   AltName: Full=Mitochondrial cytochrome b reductase B;
GN   Name=MCR1B; ORFNames=Kpol_529p19;
OS   Vanderwaltozyma polyspora (strain ATCC 22028 / DSM 70294 / BCRC 21397 / CBS
OS   2163 / NBRC 10782 / NRRL Y-8283 / UCD 57-17) (Kluyveromyces polysporus).
OC   Eukaryota; Fungi; Dikarya; Ascomycota; Saccharomycotina; Saccharomycetes;
OC   Saccharomycetales; Saccharomycetaceae; Vanderwaltozyma.
OX   NCBI_TaxID=436907;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 22028 / DSM 70294 / BCRC 21397 / CBS 2163 / NBRC 10782 /
RC   NRRL Y-8283 / UCD 57-17;
RX   PubMed=17494770; DOI=10.1073/pnas.0608218104;
RA   Scannell D.R., Frank A.C., Conant G.C., Byrne K.P., Woolfit M., Wolfe K.H.;
RT   "Independent sorting-out of thousands of duplicated gene pairs in two yeast
RT   species descended from a whole-genome duplication.";
RL   Proc. Natl. Acad. Sci. U.S.A. 104:8397-8402(2007).
CC   -!- FUNCTION: May mediate the reduction of outer membrane cytochrome b5.
CC       {ECO:0000250}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=2 Fe(III)-[cytochrome b5] + NADH = 2 Fe(II)-[cytochrome b5] +
CC         NAD(+) + H(+); Xref=Rhea:RHEA:46680, Rhea:RHEA-COMP:10438, Rhea:RHEA-
CC         COMP:10439, ChEBI:CHEBI:15378, ChEBI:CHEBI:29033, ChEBI:CHEBI:29034,
CC         ChEBI:CHEBI:57540, ChEBI:CHEBI:57945; EC=1.6.2.2;
CC   -!- COFACTOR:
CC       Name=FAD; Xref=ChEBI:CHEBI:57692; Evidence={ECO:0000250};
CC   -!- SUBCELLULAR LOCATION: Mitochondrion outer membrane {ECO:0000250};
CC       Single-pass membrane protein {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the flavoprotein pyridine nucleotide cytochrome
CC       reductase family. {ECO:0000305}.
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DR   EMBL; DS480420; EDO16639.1; -; Genomic_DNA.
DR   RefSeq; XP_001644497.1; XM_001644447.1.
DR   SMR; A7TM72; -.
DR   STRING; 436907.A7TM72; -.
DR   GeneID; 5544798; -.
DR   KEGG; vpo:Kpol_529p19; -.
DR   eggNOG; KOG0534; Eukaryota.
DR   HOGENOM; CLU_003827_9_1_1; -.
DR   InParanoid; A7TM72; -.
DR   OMA; CMHIKDD; -.
DR   OrthoDB; 432685at2759; -.
DR   PhylomeDB; A7TM72; -.
DR   CDD; cd06183; cyt_b5_reduct_like; 1.
DR   FunFam; 3.40.50.80:FF:000009; NADH-cytochrome b5 reductase; 1.
DR   Gene3D; 3.40.50.80; Nucleotide-binding domain of ferredoxin-NADP reductase (FNR) module; 1.
DR   Gene3D; 2.40.30.10; Translation factors; 1.
DR   InterPro; IPR001834; CBR-like.
DR   InterPro; IPR008333; Cbr1-like_FAD-bd_dom.
DR   InterPro; IPR017927; FAD-bd_FR_type.
DR   InterPro; IPR001709; Flavoprot_Pyr_Nucl_cyt_Rdtase.
DR   InterPro; IPR039261; FNR_nucleotide-bd.
DR   InterPro; IPR001433; OxRdtase_FAD/NAD-bd.
DR   InterPro; IPR017938; Riboflavin_synthase-like_b-brl.
DR   PANTHER; PTHR19370; NADH-CYTOCHROME B5 REDUCTASE; 1.
DR   PANTHER; PTHR19370:SF171; NADH-CYTOCHROME B5 REDUCTASE 2; 1.
DR   Pfam; PF00970; FAD_binding_6; 1.
DR   Pfam; PF00175; NAD_binding_1; 1.
DR   PRINTS; PR00406; CYTB5RDTASE.
DR   PRINTS; PR00371; FPNCR.
DR   SUPFAM; SSF52343; Ferredoxin reductase-like, C-terminal NADP-linked domain; 1.
DR   SUPFAM; SSF63380; Riboflavin synthase domain-like; 1.
DR   PROSITE; PS51384; FAD_FR; 1.
DR   GO; GO:0005741; C:mitochondrial outer membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0090524; F:cytochrome-b5 reductase activity, acting on NADH; IEA:UniProtKB-EC.
DR   GO; GO:0006696; P:ergosterol biosynthetic process; IEA:TreeGrafter.
DR   Proteomes; UP000000267; Unassembled WGS sequence.
DR   AlphaFoldDB; A7TM72; -.
PE   3: Inferred from homology;
KW   FAD; Flavoprotein; Membrane; Mitochondrion; Mitochondrion outer membrane;
KW   NAD; Oxidoreductase; Reference proteome; Transmembrane;
KW   Transmembrane helix.
FT   CHAIN           1..306
FT                   /note="NADH-cytochrome b5 reductase 2-B"
FT                   /id="PRO_0000330193"
FT   TRANSMEM        12..32
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   DOMAIN          53..157
FT                   /note="FAD-binding FR-type"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00716"
FT   BINDING         160..195
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   306 AA;  33628 MW;  82800A04590324D5 CRC64;
     MISSFTSLGS RPLLLSSGIA VTAAAAVYFS TGSRLANEAL HNKTFKGFKG PASTWVDLPL
     VKFEDLSHDT RKFTFKLPND DDVSGISPLS FLLARPHGTW SLRGIRPYTP VSLPETQGVI
     EFVIKHVPNG GMSSHMFSLK PNDTVSFTGP IVKYEWKQNK FDSVTLLGAG SGITPLYQLM
     GSILSNPEDK TKINLFYANK TSDDILLKKE LDEFQQKFSD RVKIHYYLSQ PKTKDIASTG
     AKKGFIAKED IESLAPASNE NTHVFVCGPE PFVKAYAGQQ GPLFFQGSFG GILKELGYTK
     SQVFKV
//