Protein Family Models

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]. 10217509. 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. [2]. 12207230. 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. [3]. 11941510. 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. (from Pfam)

Date:

2024-10-16

HesB/IscA family protein is a scaffold protein upon which 2Fe-2S clusters are assembled and subsequently transferred to acceptor proteins; similar to iron-sulfur assembly protein IscA that is involved in the maturation of mitochondrial 4Fe-4S proteins functioning late in the iron-sulfur cluster assembly pathway

Date:

2024-06-28

Proteins in this subfamily appear to be associated with the process of FeS-cluster assembly. The HesB proteins are associated with the nif gene cluster and the Rhizobium gene IscN has been shown to be required for nitrogen fixation [1]. Nitrogenase includes multiple FeS clusters and many genes for their assembly. The E. coli SufA protein is associated with SufS, a NifS homolog and SufD which are involved in the FeS cluster assembly of the FhnF protein [2]. The Azotobacter protein IscA (homologs of which are also found in E.coli) is associated which IscS, another NifS homolog and IscU, a nifU homolog as well as other factors consistent with a role in FeS cluster chemistry [3]. A homolog from Geobacter contains a selenocysteine in place of an otherwise invariant cysteine, further suggesting a role in redox chemistry.

Date:

2024-06-27