Bacterial production of gaseous hydrocarbons such as ethylene and methane affects soil environments and atmospheric climate. We demonstrate that biogenic methane and ethylene from terrestrial and freshwater bacteria are directly produced by a previously unknown methionine biosynthesis pathway. This pathway, present in numerous species, uses a nitrogenase-like reductase that is distinct from known nitrogenases and nitrogenase-like reductases and specifically functions in C-S bond breakage to reduce ubiquitous and appreciable volatile organic sulfur compounds such as dimethyl sulfide and (2-methylthio)ethanol.
View Article and Find Full Text PDFThe mammalian protein paraoxonase-1 (PON1) has been explored as a promising bioscavenger treatment for organophosphorus (OP) agent poisoning, but it is not active enough to protect against many agents. Engineering is limited because PON1's catalytic mechanism is poorly understood; moreover, its native activity and substrate are unknown. PON1 is a calcium-bound six-bladed β-propeller hydrolase that shares high structural homology, a conserved metal-coordinating active site, and substrate specificity overlap with other members of a superfamily that includes squid diisopropylfluorophosphatase, bacterial drug responsive protein 35, and mammalian senescence marker protein 30.
View Article and Find Full Text PDF