Reaction: hydrogen sulfide + 6 oxidized ferredoxin [iron-sulfur] cluster + 3 H2O = sulfite + 6 reduced ferredoxin [iron-sulfur] cluster + 6 H+
Other name(s): ferredoxin-sulfite reductase; SIR (gene name); sulfite reductase (ferredoxin)
Systematic name: hydrogen-sulfide:ferredoxin oxidoreductase
Comments: An iron protein. The enzyme participates in sulfate assimilation. While it is usually found in cyanobacteria, plants and algae, it has also been reported in bacteria [4]. Different from EC 1.8.1.22, dissimilatory sulfite reductase system, which is involved in prokaryotic sulfur-based energy metabolism. cf. EC 1.8.1.2, assimilatory sulfite reductase (NADPH).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 37256-50-1
References:
1. Schmidt, A. and Trebst, A. The mechanism of photosynthetic sulfate reduction by isolated chloroplasts. Biochim. Biophys. Acta 180 (1969) 529-535. [PMID: 4390248]
2. Gisselmann, G., Klausmeier, P. and Schwenn, J.D. The ferredoxin:sulphite reductase gene from Synechococcus PCC7942. Biochim. Biophys. Acta 1144 (1993) 102-106. [PMID: 8347657]
3. Bork, C., Schwenn, J.D. and Hell, R. Isolation and characterization of a gene for assimilatory sulfite reductase from Arabidopsis thaliana. Gene 212 (1998) 147-153. [PMID: 9661674]
4. Neumann, S., Wynen, A., Truper, H.G. and Dahl, C. Characterization of the cys gene locus from Allochromatium vinosum indicates an unusual sulfate assimilation pathway. Mol. Biol. Rep. 27 (2000) 27-33. [PMID: 10939523]