Molecular genetic studies of microbial Se(VI) reduction

Microorganisms play a major role in driving the global selenium cycle by catalyzing the reduction of selenium in soils and sediments. Although subsurface microorganisms have been known to reduce selenium oxyanions over 20 years, the molecular mechanisms that control the reduction reaction have remained unresolved. We are currently applying molecular genetic techniques to investigate the molecular determinants that govern selenate [Se(VI), SeO₄^2-] reduction activity in Se-reducing bacteria. By employing direct cloning and mutagenesis methods, we have identified essential genes that are required for selenate reduction. This genetic data has allowed us to construct a molecular model for microbial selenate reduction.

Collaborator: Donald Kobayashi

A molecular model for selenate [Se(VI), SeO₄^2-] reduction by Enterobacter cloacae SLD1a-1. The model depicts the role of FNR, TatABC, and menaquinone in the selenate reduction process. (Yee and Kobayashi, 2008)