Analysis of a microbe thriving in the harsh salty conditions of the Dead Sea has revealed a novel pathway for metabolizing carbon.

Ivan Berg at the University of Freiburg in Germany and his colleagues discovered the methylaspartate cycle by studying the enzymes and intermediates involved in metabolism when Haloarcula marismortui is grown on acetate. The pathway converts a molecule called acetyl coenzyme A into the building blocks of sugars, and is only the third such metabolic pathway identified. Among other features, one intermediate of the complex cycle limits the effects of osmosis, helping the microbe to survive in high-salt environments.

The researchers found striking similarities between the enzymes of H. marismortui and those found in some ancient bacteria — an indication that the microbe probably acquired components of this pathway by grabbing genes from other species.

Science 331, 334–337 (2011)