Genetic identification of the selenate reductase in <i>Enterobacter cloacae</i> SLD1a-1

Selenium pollution poses risks to ecosystems and human health, largely due to the mobility and toxicity of selenate, a common form found in soil and water. Diverse bacterial species are able to convert soluble selenate into insoluble elemental selenium, but the genes and enzymes that underpin this process are not fully understood. In this study, we identified a gene in <i>Enterobacter cloacae</i> SLD1a-1 that enables the bacterium to catalyze selenate reduction. We showed that this gene produces a functional enzyme even when it is transferred into a different species, <i>Escherichia coli</i>. Protein structure modeling revealed features of the enzyme that help it recognize and reduce selenate. This information advances our understanding of how selenium is enzymatically cycled in the environment.