This family is involved in iron-sulphur cluster biosynthesis [3]. Its members include proteins that are involved in nitrogen fixation such as the HesB and HesB-like proteins [1] [2].

1: Organization and expression of nitrogen-fixation genes in the aerobic nitrogen-fixing unicellular cyanobacterium Synechococcus sp. strain RF-1. Huang TC, Lin RF, Chu MK, Chen HM; Microbiology 1999;145:743-753. PMID:10217509

2: The Rhizobium etli gene iscN is highly expressed in bacteroids and required for nitrogen fixation. Dombrecht B, Tesfay MZ, Verreth C, Heusdens C, Napoles MC, Vanderleyden J, Michiels J; Mol Genet Genomics 2002;267:820-828. PMID:12207230

3: Iron-sulfur cluster biosynthesis: characterization of Schizosaccharomyces pombe Isa1. Wu G, Mansy SS, Hemann C, Hille R, Surerus KK, Cowan JA; J Biol Inorg Chem 2002;7:526-532. PMID:11941510