Sulphite reductase [NADPH] flavoprotein, alpha chain, Proteobacteria (IPR029758)

Short name: CysJ_Proteobact

Overlapping homologous superfamilies

Family relationships


Escherichia coli NADPH-sulphite reductase (SiR) is a multimeric hemoflavoprotein composed of eight alpha-subunits (SiR-FP) and four beta-subunits (SiR-HP) that catalyses the six electron reduction of sulphite to sulphide. This is one of several activities required for the biosynthesis of L-cysteine from sulphate. The alpha component of NADPH-sulphite reductase is a flavoprotein, the beta component is a hemoprotein [PMID: 10984484]. The flavoprotein component catalyses the electron flow from NADPH to FAD to FMN to the hemoprotein component.

This entry describes a clade of NADPH-dependent sulphite reductase flavoprotein subunit alpha from Proteobacteria. The proteins bind one FAD and one FMN as prosthetic groups and contains an NADPH-binding domain [PMID: 10860732].

GO terms

Biological Process

GO:0019344 cysteine biosynthetic process
GO:0055114 oxidation-reduction process
GO:0000103 sulfate assimilation

Molecular Function

GO:0010181 FMN binding
GO:0050660 flavin adenine dinucleotide binding
GO:0004783 sulfite reductase (NADPH) activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.