ID   CHLB_NEPEX              Reviewed;         103 AA.
AC   P37850;
DT   01-OCT-1994, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1994, sequence version 1.
DT   25-MAY-2022, entry version 74.
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   Nephrolepis exaltata (Boston sword fern) (Polypodium exaltatum).
OG   Plastid; Chloroplast.
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Polypodiopsida; Polypodiidae; Polypodiales; Polypodiineae;
OC   Nephrolepidaceae; Nephrolepis.
OX   NCBI_TaxID=34165;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=8812302; DOI=10.1006/mpev.1996.0054;
RA   Boivin R., Richard M., Beauseigle D., Bousquet J., Bellemare G.;
RT   "Phylogenetic inferences from chloroplast chlB gene sequences of
RT   Nephrolepis exaltata (Filicopsida), Ephedra altissima (Gnetopsida), and
RT   diverse land plants.";
RL   Mol. Phylogenet. Evol. 6:19-29(1996).
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   EMBL; L25770; AAC37491.1; -; Genomic_DNA.
DR   AlphaFoldDB; P37850; -.
DR   SMR; P37850; -.
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:0016491; F:oxidoreductase activity; IEA:UniProtKB-KW.
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   Pfam; PF00148; Oxidored_nitro; 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..>103
FT                   /note="Light-independent protochlorophyllide reductase
FT                   subunit B"
FT                   /id="PRO_0000219832"
FT   NON_TER         1
FT   NON_TER         103
SQ   SEQUENCE   103 AA;  11787 MW;  63F868367CD32F77 CRC64;
     KRLLGESGIA VNQVIPEGGY LNYLKDLPRA WFNIVPYREV GLMTAIFSEK EYGMPYISIT
     PMGISNTANF IAQIEKLVNM WASALSEKRL NYKFYVDNQT KFV