ID   CHLB_CHLAT              Reviewed;         510 AA.
AC   Q19V92;
DT   18-MAR-2008, integrated into UniProtKB/Swiss-Prot.
DT   20-FEB-2007, sequence version 2.
DT   03-AUG-2022, entry version 61.
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=chlB {ECO:0000255|HAMAP-Rule:MF_00353};
OS   Chlorokybus atmophyticus (Soil alga).
OG   Plastid; Chloroplast.
OC   Eukaryota; Viridiplantae; Streptophyta; Chlorokybophyceae; Chlorokybales;
OC   Chlorokybaceae; Chlorokybus.
OX   NCBI_TaxID=3144;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=SAG 48.80;
RX   PubMed=17222354; DOI=10.1186/1741-7007-5-2;
RA   Lemieux C., Otis C., Turmel M.;
RT   "A clade uniting the green algae Mesostigma viride and Chlorokybus
RT   atmophyticus represents the deepest branch of the Streptophyta in
RT   chloroplast genome-based phylogenies.";
RL   BMC Biol. 5:2-2(2007).
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 (ChlN-ChlB) 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; chlorophyll
CC       biosynthesis (light-independent). {ECO:0000255|HAMAP-Rule:MF_00353}.
CC   -!- SUBUNIT: Protochlorophyllide reductase is composed of three subunits;
CC       ChlL, ChlN and ChlB. Forms a heterotetramer of two ChlB and two ChlN
CC       subunits. {ECO:0000255|HAMAP-Rule:MF_00353}.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast.
CC   -!- SIMILARITY: Belongs to the ChlB/BchB/BchZ family. {ECO:0000255|HAMAP-
CC       Rule:MF_00353}.
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DR   EMBL; DQ422812; ABD62177.2; -; Genomic_DNA.
DR   RefSeq; YP_001019110.1; NC_008822.1.
DR   AlphaFoldDB; Q19V92; -.
DR   SMR; Q19V92; -.
DR   GeneID; 4783226; -.
DR   UniPathway; UPA00670; -.
DR   GO; GO:0009507; C:chloroplast; IEA:UniProtKB-SubCell.
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:0036068; P:light-independent chlorophyll 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; Chlorophyll biosynthesis; Chloroplast; Iron;
KW   Iron-sulfur; Metal-binding; Nucleotide-binding; Oxidoreductase;
KW   Photosynthesis; Plastid.
FT   CHAIN           1..510
FT                   /note="Light-independent protochlorophyllide reductase
FT                   subunit B"
FT                   /id="PRO_0000324047"
FT   ACT_SITE        296
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         431..432
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00353"
SQ   SEQUENCE   510 AA;  57474 MW;  37BA8884272F5630 CRC64;
     MKLAYWMYAG PAHIGTLRVA SSFKNVHAIM HAPLGDDYFN VMRSMLERER DFTPVTASIV
     DRHVLARGSQ NKVVENITRK DKEERPDLIV LTPTCTSSIL QEDLQNFVDR ASMDSESDVI
     LADVNHYRVN ELQAADRTLE QVVRFYIEKS KKQGDLNLTK TEKPSANILG IFTLGFHNQH
     DCRELKRLLQ ELGIEINEVI PEGGSVNNLK NLPRAWFNLV PYREVGLMTA IYLEKEFGMP
     YVSTTPMGVV DTATCIREIE KILNSFDKDV VVDFESYIDK QTRFVSQAAW FSRSIDCQNL
     TGKKAVVFGD ATHAASMTKI LAREMGINVA CAGTYCKHDA DWFKEQVQGY CDEVLITDDH
     TEVGDLIARI EPSAIFGTQM ERHIGKRLNI PCGVISAPVH IQNFPLGYRP FLGYEGTNQI
     ADLVYNSFTL GMEDHLLEIF GGHDTKEVIT KSLSTEEGLT WTSDAQAELS KIPGFVRGKI
     KRNTEKFARE NNISEINIEV MYAAKESLNA