ID   BCHB_HELMI              Reviewed;         520 AA.
AC   B0TBM8;
DT   28-JUL-2009, integrated into UniProtKB/Swiss-Prot.
DT   08-APR-2008, sequence version 1.
DT   03-AUG-2022, entry version 71.
DE   RecName: Full=Light-independent protochlorophyllide reductase subunit B;
DE            Short=DPOR subunit B;
DE            Short=LI-POR subunit B;
DE            EC=1.3.7.7;
GN   Name=bchB; OrderedLocusNames=Helmi_12420; ORFNames=HM1_0685;
OS   Heliobacterium modesticaldum (strain ATCC 51547 / Ice1).
OC   Bacteria; Firmicutes; Clostridia; Eubacteriales; Heliobacteriaceae;
OC   Heliomicrobium.
OX   NCBI_TaxID=498761;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 51547 / Ice1;
RX   PubMed=18441057; DOI=10.1128/jb.00299-08;
RA   Sattley W.M., Madigan M.T., Swingley W.D., Cheung P.C., Clocksin K.M.,
RA   Conrad A.L., Dejesa L.C., Honchak B.M., Jung D.O., Karbach L.E.,
RA   Kurdoglu A., Lahiri S., Mastrian S.D., Page L.E., Taylor H.L., Wang Z.T.,
RA   Raymond J., Chen M., Blankenship R.E., Touchman J.W.;
RT   "The genome of Heliobacterium modesticaldum, a phototrophic representative
RT   of the Firmicutes containing the simplest photosynthetic apparatus.";
RL   J. Bacteriol. 190:4687-4696(2008).
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 (By similarity). {ECO:0000250}.
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   -!- COFACTOR:
CC       Name=[4Fe-4S] cluster; Xref=ChEBI:CHEBI:49883; Evidence={ECO:0000250};
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:0000250};
CC   -!- PATHWAY: Porphyrin-containing compound metabolism; bacteriochlorophyll
CC       biosynthesis (light-independent).
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 (By similarity). {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the ChlB/BchB/BchZ family. {ECO:0000305}.
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DR   EMBL; CP000930; ABZ83867.1; -; Genomic_DNA.
DR   AlphaFoldDB; B0TBM8; -.
DR   SMR; B0TBM8; -.
DR   STRING; 498761.HM1_0685; -.
DR   EnsemblBacteria; ABZ83867; ABZ83867; HM1_0685.
DR   KEGG; hmo:HM1_0685; -.
DR   eggNOG; COG2710; Bacteria.
DR   HOGENOM; CLU_025470_0_0_9; -.
DR   OMA; NDNIHRE; -.
DR   UniPathway; UPA00671; -.
DR   Proteomes; UP000008550; Chromosome.
DR   GO; GO:0051539; F:4 iron, 4 sulfur cluster binding; IEA:UniProtKB-KW.
DR   GO; GO:0005524; F:ATP binding; IEA:UniProtKB-KW.
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: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   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; Reference proteome.
FT   CHAIN           1..520
FT                   /note="Light-independent protochlorophyllide reductase
FT                   subunit B"
FT                   /id="PRO_1000133423"
FT   ACT_SITE        281
FT                   /note="Proton donor"
FT                   /evidence="ECO:0000250"
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:0000250"
FT   BINDING         416..417
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   520 AA;  57777 MW;  EC0CADD1B4E8FDF7 CRC64;
     MKLAYWMYEG TALSGIARVA GSMPKVHTVI HGPQGDGYIN VMFSMLERFH KLPPFTLSPI
     GRREMARGSR ARLVETVRRV DALHQPDVIV ITPTCSSTLL QEDLLAVANS LGRQTKARLI
     VPQVNAFRDL EHFAMDDFLA QMVAAFAVEQ PKTERFTVNL IGPSYLGFHQ IHDLNEIRTM
     LEEIGIGVNA VIPYGATVET LRSLTRAHLN ICLYREYGRE TCEYLRKRFG IDYISITPMG
     IRQTGRFLRA LGEQAGIDVT PYIRRHLAPS GALARFTKSV DALSSLFGKR AVVFGDFSHA
     VGATYLLREI GLQVVWAGTY MTAWKDEFTE AVAALTDEAF VCDDFQAVSR KIRDTQPDIV
     FGTQMERHSA ARYELPCIVI SSPAHILNFP LFPAPVLGYR GMTRLLDTIN QTIKLGLEEH
     LVNMFGEDTA SERQMEAASA AARGTATAPT GAAGAVATVD ELQWDAEAEK ALKQVPFFVR
     GKVQRNTENY ARERGYSEVT LDVIYAAKAY FEGKGNQGNR