WIKIMEDIA COMMONS, Michael Gäbler A few degrees difference in a single hydrogen bond angle prevents bacteria from importing arsenate in place of phosphate, a molecule integral to energy production, DNA, and enzymatic cascades, according to a new study published today (October 3) in Nature. Arsenate is structurally very similar to phosphate, but the new research shows that certain proteins responsible for importing phosphate are unable to handle arsenate’s slightly larger size, which warps a key hydrogen bond, allowing certain bacterial species grow in high-arsenate environments.
The findings “show how a gatekeeper [protein] keeps arsenate out [of bacteria], so levels don’t accumulate and the bacteria don’t have to worry about toxic effects,” said Ronald Viola, a chemist at the University of Toledo who was not involved in the research.
The study drives a nail in the coffin of a 2010 Science paper in which NASA researchers claimed to have discovered a strain of Halomonas bacteria in Mono Lake, California, that incorporated arsenate, instead of phosphate, into its DNA backbone. The study generated a stir in the scientific community, drawing much press and criticism. The findings were subsequently refuted by several studies, though the paper has not been retracted.
The new work provides a mechanistic explanation for how the bacteria in Mono ...
