Identifying the Nature of Iron‐Sulfur Clusters in the CDGSH‐Family Protein AlVin0680

Abstract

The CDGSH domain is a small [2Fe‐2S] cluster binding domain typified by the presence of three ligating cysteines and one ligating histidine residue. The human protein mitoNEET, an example of a CDGSH domain protein, has attracted interest due to its interaction with the type II diabetes drug pioglitazone. A greater understanding of other CDGSH domain containing proteins may provide insight into the functional role of the unique [2Fe‐2S] cluster. The Allochromatium vinosum protein, AlVin0680, has been identified as a domain fusion protein consisting of two CDGSH domains and a putative [3Fe‐4S] cluster binding DUF1271 domain. Basic characterization of AlVin0680 via UV/Vis spectroscopy, EPR, protein film voltammetry, and colorimetric assays of the iron content indicate that both the mitoNEET‐like CDGSH clusters and the DUF1271 clusters are bound by the protein. Further work will involve the exploration of the potential interactions between the two [2Fe‐2S] clusters and the [3Fe‐4S] cluster, specifically determining whether electron or cluster exchange occurs between the three clusters. A greater understanding of the iron‐sulfur clusters in AlVin0680 may provide insight into the general function of CDGSH domain proteins and their iron‐sulfur clusters.