Abstract
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. Liberated methanethiol serves as the immediate precursor to methionine, while ethylene or methane is released into the environment. Anaerobic ethylene production by this pathway apparently explains the long-standing observation of ethylene accumulation in oxygen-depleted soils. Methane production reveals an additional bacterial pathway distinct from archaeal methanogenesis.
| Original language | English |
|---|---|
| Pages (from-to) | 1094-1098 |
| Number of pages | 5 |
| Journal | Science |
| Volume | 369 |
| Issue number | 6507 |
| DOIs | |
| State | Published - Aug 28 2020 |
Funding
We thank D. Canniffe (University of Liverpool) for providing Blastochloris viridis. Electronic structure calculations were performed at the Environmental Molecular Sciences Laboratory (EMSL), a National Scientific User Facility sponsored by the U.S. Department of Energy (DOE), Office of Science, Biological and Environmental Research (BER) and located at Pacific Northwest National Laboratory, which is operated by Battelle, for the U.S. DOE under contract DE-AC05-76RLO 1830. Transcriptomics work was supported in part by the University of Colorado Cancer Center’s Genomics and Microarray Shared Resource (NCI grant P30CA046934) with RNA sequencing services performed by K. Diener. Computational aspects used resources from the University of Colorado Boulder Research Computing Group, which is supported by the National Science Foundation (awards ACI-1532235 and ACI-1532236), the University of Colorado Boulder, and Colorado State University. Proteomics work at Oak Ridge National Laboratory (ORNL) was supported by the Genomic Science Program, U.S. DOE, Office of Science, BER as part of the Plant Microbe Interfaces Scientific Focus Area (http://pmiweb.ornl.gov). ORNL is managed by UT-Battelle, LLC, for the DOE under contract number DE-AC05-00OR22725. This work was supported by an OSU Center for Applied Plant Sciences Grant (to F.R.T.) and the Genomic Science Program, U.S. DOE, Office of Science, BER under award number DE-SC0019338 (to F.R.T., K.C.W., and W.R.C.).