Bacterial aging

The discovery of a novel substrate for CobB, a bacterial Sir2 protein, has provided a link between a cell's energy status and carbon usage. The finding, described by Vincent Starai, Jorge Escalante-Semerena (University of Wisconsin, Madison, WI), and colleagues, may also help explain how Sir2 slows aging in yeast, worms, and, perhaps, mammals.

The team started out with a mutant, cobB^–, that could not grow on low levels of acetate. They found that the acetyl coenzyme A (CoA) synthetase (Acs) that initially derivatizes acetate to form acetyl CoA was inactive because of acetylation of a specific lysine residue of Acs. CobB, the bacterial Sir2, removed this acetylation and thus activated Acs.

The link to energy status and redox comes about through NAD⁺. A bacterial cell that is low in energy will use...