ID   CHLB_CHLPT              Reviewed;         444 AA.
AC   P37824;
DT   01-OCT-1994, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1994, sequence version 1.
DT   03-AUG-2022, entry version 75.
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;
DE   Flags: Fragment;
GN   Name=chlB;
OS   Chlamydomonas pitschmannii.
OG   Plastid; Chloroplast.
OC   Eukaryota; Viridiplantae; Chlorophyta; core chlorophytes; Chlorophyceae;
OC   CS clade; Chlamydomonadales; Chlamydomonadaceae; Chlamydomonas.
OX   NCBI_TaxID=3061;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=8219066; DOI=10.1007/bf00029006;
RA   Liu X.-Q., Xu H., Huang C.;
RT   "Chloroplast chlB gene is required for light-independent chlorophyll
RT   accumulation in Chlamydomonas reinhardtii.";
RL   Plant Mol. Biol. 23:297-308(1993).
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 (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; chlorophyll
CC       biosynthesis (light-independent).
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 (By similarity). {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast.
CC   -!- SIMILARITY: Belongs to the ChlB/BchB/BchZ family. {ECO:0000305}.
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DR   AlphaFoldDB; P37824; -.
DR   SMR; P37824; -.
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-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:0036068; P:light-independent chlorophyll biosynthetic process; IEA:UniProtKB-UniPathway.
DR   GO; GO:0015979; P:photosynthesis; IEA:UniProtKB-KW.
DR   InterPro; IPR000510; Nase/OxRdtase_comp1.
DR   InterPro; IPR016209; Protochlorophyllide_Rdtase.
DR   Pfam; PF00148; Oxidored_nitro; 2.
DR   PIRSF; PIRSF000163; PCP_ChlB; 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..>444
FT                   /note="Light-independent protochlorophyllide reductase
FT                   subunit B"
FT                   /id="PRO_0000219816"
FT   ACT_SITE        354
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   NON_TER         444
SQ   SEQUENCE   444 AA;  50058 MW;  6906E52CAAE4857F CRC64;
     MKLAYWMYAG PAHIGTLRVA SSFKNVHAIM HAPLGDDYFN VMRSMLERER DFTPVTTSIV
     DRHVLARGSQ EKVVENITRK DNEEAPDLIT LTPTCTSSIL QEDLQIFVNR ASISESNNGH
     SGIDKATSDV ILADVNHYRV NELQAADRTL EQIVRFYLEK EKKLNTNTIP TKTKKPSANI
     IGIFTLGFHN QHDCRELKRL LNNLGIEVNE IIPEGGSVTN LKNLPHAWFN LVPYREIGLM
     RAVYLEKEFN MPYVAISPLG IIDTAVCIRE IEKILNNLSL NGYQSSLPEG HKLTNEELNG
     LSQKNNEPSL PEEHRQLDGA LDSKSQKTYN FENKYIKQQT RFISQAAWFS RSIDCLNLTA
     KKAVVFGDAT HAAGITKILA REMGIKVVCS GTYCKHDADW FREQVVGFCD QILVTDDHTQ
     VGDMIAKLEP SAIFGTQMER HIGR