Microorganisms harvest lysine to protect themselves against oxidative stress

Glutathione and NADPH have a key role in preventing oxidative stress and maintaining proper cell function. Olin-Sandoval et al. report a thus far unknown cellular strategy developed in budding yeast for coping with oxidative stress. Yeast harvests lysine from the environment and uses it for metabolic rewiring that enables it to conserve more NADPH and maintain a much larger glutathione pool, all in the service of increased stress tolerance. The harvested lysine reaches intracellular concentrations that can be two orders of magnitude higher than the concentrations required for growth, which is made possible by a promiscuous enzymatic reaction that turns lysine into cadaverine. This powerful preventative and conditional metabolic antioxidant strategy is not limited only to budding yeast; it is also detected in other microbial cells.