ID   CHLB_AUXPR              Reviewed;         510 AA.
AC   Q6VQA8;
DT   21-JUN-2005, integrated into UniProtKB/Swiss-Prot.
DT   05-JUL-2004, sequence version 1.
DT   03-AUG-2022, entry version 64.
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   Auxenochlorella protothecoides (Green microalga) (Chlorella
OS   protothecoides).
OG   Plastid; Chloroplast.
OC   Eukaryota; Viridiplantae; Chlorophyta; core chlorophytes; Trebouxiophyceae;
OC   Chlorellales; Chlorellaceae; Auxenochlorella.
OX   NCBI_TaxID=3075;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=CS-41;
RA   Shi C., Shi X.;
RT   "Cloning of LIPOR genes from Chlorella protothecoides CS-41 and their
RT   expression in E. coli BL21.";
RL   Submitted (JUN-2003) to the EMBL/GenBank/DDBJ databases.
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; AY331983; AAP93907.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q6VQA8; -.
DR   SMR; Q6VQA8; -.
DR   BRENDA; 1.3.7.7; 1329.
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_0000219815"
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;  57539 MW;  341887B7A1DFFEAB CRC64;
     MKLAYWMYAG PAHIGTLRVA SSFKNVHAIM HAPLGDDYFN VMRSMLERER DFTPVTASIV
     DRHVLARGSQ EKVIENITRK DKEENPDLII LTPTCTSSIL QEDLQNFVNR AGLDSKSDVI
     LADVNHYRVN ELQAADRTLE QIIRFYLEKA RSQSNEPLRK TEKPSANILG IFTLGFHNQH
     DCRELKRLLT DLGIVINQIL PEGGSVTNIN ELPKAWFNLI PYREVGLMAA NYLKNEYDMP
     YVAVTPMGLL DTENCIREIV DIVKSSDTSY NFDFETYIDT QTRFISQAAW FSRSIDCQNL
     TGKKAVVFGD ATHAASITKI LAREMGIRVS CSGTYCKHDA DWFREQVDGF CDEVLITDDH
     TQVADMIARI EPAAIFGTQM ERHIGKRLDI PCGVISAPVH IQNFPLGFRP FLGYEGTNQI
     SDLVYNSFTL GMEDHLLEIF GGHDTKEVIT KSLSTDSDLA WAPEALTELQ RIPGFVRGKI
     KRNTEKFARE KNCNLITLEI MFAAKEAVGA