Cellular and molecular basis of atmospheric hydrogen and carbon monoxide oxidation in mycobacteria

This study improves understanding of how mycobacteria, a group of environmentally and medically important bacteria, use trace gases as energy sources. Here I show that the model organism Mycobacterium smegmatis uses the dependable energy sources atmospheric hydrogen and carbon monoxide to survive nutrient starvation. They do so by synthesizing specific enzymes, namely hydrogenases and carbon monoxide dehydrogenases, in response to organic carbon levels. These enzymes are physically and functionally integrated with the aerobic respiratory chain and, when lost, cause survival defects. In turn, these findings provide new cellular and biochemical insights into how bacteria control the composition of the atmosphere.