ID   BCHB_ACIRU              Reviewed;         504 AA.
AC   Q9WXB5;
DT   27-APR-2001, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1999, sequence version 1.
DT   03-AUG-2022, entry version 73.
DE   RecName: Full=Light-independent protochlorophyllide reductase subunit B {ECO:0000255|HAMAP-Rule:MF_00353};
DE            Short=DPOR subunit B {ECO:0000255|HAMAP-Rule:MF_00353};
DE            Short=LI-POR subunit B {ECO:0000255|HAMAP-Rule:MF_00353};
DE            EC=1.3.7.7 {ECO:0000255|HAMAP-Rule:MF_00353};
GN   Name=bchB {ECO:0000255|HAMAP-Rule:MF_00353};
OS   Acidiphilium rubrum.
OC   Bacteria; Proteobacteria; Alphaproteobacteria; Rhodospirillales;
OC   Acetobacteraceae; Acidiphilium.
OX   NCBI_TaxID=526;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=10559247; DOI=10.1074/jbc.274.47.33594;
RA   Masuda T., Inoue K., Masuda M., Nagayama M., Tamaki A., Ohta H.,
RA   Shimada H., Takamiya K.;
RT   "Magnesium insertion by magnesium chelatase in the biosynthesis of zinc
RT   bacteriochlorophyll a in an aerobic acidophilic bacterium Acidiphilium
RT   rubrum.";
RL   J. Biol. Chem. 274:33594-33600(1999).
CC   -!- FUNCTION: Component of the dark-operative protochlorophyllide reductase
CC       (DPOR) that uses Mg-ATP and reduced ferredoxin to reduce ring D of
CC       protochlorophyllide (Pchlide) to form chlorophyllide a (Chlide). This
CC       reaction is light-independent. The NB-protein (BchN-BchB) is the
CC       catalytic component of the complex. {ECO:0000255|HAMAP-Rule:MF_00353}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=2 ADP + chlorophyllide a + oxidized 2[4Fe-4S]-[ferredoxin] + 2
CC         phosphate = 2 ATP + 2 H2O + protochlorophyllide a + reduced 2[4Fe-
CC         4S]-[ferredoxin]; Xref=Rhea:RHEA:28202, Rhea:RHEA-COMP:10002,
CC         Rhea:RHEA-COMP:10004, ChEBI:CHEBI:15377, ChEBI:CHEBI:30616,
CC         ChEBI:CHEBI:33722, ChEBI:CHEBI:33723, ChEBI:CHEBI:43474,
CC         ChEBI:CHEBI:83348, ChEBI:CHEBI:83350, ChEBI:CHEBI:456216; EC=1.3.7.7;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_00353};
CC   -!- COFACTOR:
CC       Name=[4Fe-4S] cluster; Xref=ChEBI:CHEBI:49883;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_00353};
CC       Note=Binds 1 [4Fe-4S] cluster per heterodimer. The cluster is bound at
CC       the heterodimer interface by residues from both subunits.
CC       {ECO:0000255|HAMAP-Rule:MF_00353};
CC   -!- PATHWAY: Porphyrin-containing compound metabolism; bacteriochlorophyll
CC       biosynthesis (light-independent). {ECO:0000255|HAMAP-Rule:MF_00353}.
CC   -!- SUBUNIT: Protochlorophyllide reductase is composed of three subunits;
CC       BchL, BchN and BchB. Forms a heterotetramer of two BchB and two BchN
CC       subunits. {ECO:0000255|HAMAP-Rule:MF_00353}.
CC   -!- SIMILARITY: Belongs to the ChlB/BchB/BchZ family. {ECO:0000255|HAMAP-
CC       Rule:MF_00353}.
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DR   EMBL; AB017351; BAA76537.1; -; Genomic_DNA.
DR   RefSeq; WP_029311398.1; NZ_FTNE01000002.1.
DR   AlphaFoldDB; Q9WXB5; -.
DR   SMR; Q9WXB5; -.
DR   STRING; 526.SAMN05421828_10298; -.
DR   UniPathway; UPA00671; -.
DR   GO; GO:0051539; F:4 iron, 4 sulfur cluster binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0005524; F:ATP binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0016730; F:oxidoreductase activity, acting on iron-sulfur proteins as donors; IEA:InterPro.
DR   GO; GO:0016636; F:oxidoreductase activity, acting on the CH-CH group of donors, iron-sulfur protein as acceptor; IEA:UniProtKB-UniRule.
DR   GO; GO:0036070; P:light-independent bacteriochlorophyll biosynthetic process; IEA:UniProtKB-UniPathway.
DR   GO; GO:0019685; P:photosynthesis, dark reaction; IEA:InterPro.
DR   Gene3D; 1.10.8.550; -; 1.
DR   HAMAP; MF_00353; ChlB_BchB; 1.
DR   InterPro; IPR013580; LI-POR_suB-like_C.
DR   InterPro; IPR000510; Nase/OxRdtase_comp1.
DR   InterPro; IPR042298; P-CP_red_C.
DR   InterPro; IPR005969; Protochl_reductB.
DR   InterPro; IPR016209; Protochlorophyllide_Rdtase.
DR   Pfam; PF00148; Oxidored_nitro; 1.
DR   Pfam; PF08369; PCP_red; 1.
DR   PIRSF; PIRSF000163; PCP_ChlB; 1.
DR   TIGRFAMs; TIGR01278; DPOR_BchB; 1.
PE   3: Inferred from homology;
KW   4Fe-4S; ATP-binding; Bacteriochlorophyll biosynthesis;
KW   Chlorophyll biosynthesis; Iron; Iron-sulfur; Metal-binding;
KW   Nucleotide-binding; Oxidoreductase; Photosynthesis.
FT   CHAIN           1..504
FT                   /note="Light-independent protochlorophyllide reductase
FT                   subunit B"
FT                   /id="PRO_0000219796"
FT   ACT_SITE        279
FT                   /note="Proton donor"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00353"
FT   BINDING         36
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /ligand_note="ligand shared with heterodimeric partner"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00353"
FT   BINDING         414..415
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00353"
SQ   SEQUENCE   504 AA;  54390 MW;  FEEF8ED84ACDC8BA CRC64;
     MQLTLWTYEG PPHIGAMRIA TAMQGVHYVL HAPQGDTYAD LLFTMIERRD RRPPVTYTTF
     QARDLGSDTA TLFKNAVRDA YDRFKPEAMI VGASCTAELI QDDPGGLAAA LGLPIPVIPL
     ELPAYQRKEN WGAAETLYHL VRAATNGVAT PDRTGRPVAV NILGPAALGF RHRDDLIEVT
     DLLGKLGVSI NVIAPLGARF ADLARIPAAD ANIVLYPEIA GTAAAYLARK FGQKTITTVP
     IGLNATRDFA AEIAALTGST VPDDLESQAR SSWYARSIDS TYLTGKRVFI FGDASHAIAL
     ARIAATEIGF TIAGLGTYSR EFAREVKSAA ALYNVEALIS DDYLTVEAAI AAAQPELVLG
     TQMERHIAKR LGIPCAVISA PTHVQDFPAR HSPFAGFEGA NVLFDTLTHP LMMGLEEHLL
     GMFREDFEFN DQAAPSHLGA EAAAPVATAP ILTGWEPSAE AELKKIPFFV RGKARKNTEL
     FAAEHGVTLI TIETIYDAKA HFSR