Reverse Methanogenesis: Validating the Hypothesis with Lineage-Resolved Environmental Proteomics
EMSL Project ID
40089
Abstract
In marine sediments three known lineages of anaerobic methane oxidizing archaea (ANME-1, 2 and 3) filter up to ~384 Tg of the greenhouse gas methane annually, greatly reducing methane flux from ocean to the atmosphere. Although ANME and associated syntrophs bear the isotopic signature of methane-derived carbon in their cellular building blocks, the biochemical pathways underlying conversion of methane into biomass and energy remain unresolved. Here we describe an environmental proteomic approach used to constrain and validate the biochemical pathways mediating the anaerobic oxidation of methane (AOM). A multi-criteria binning method based on G+C content, read density, and intrinsic oligonucleotide frequency patterns in combination with multivariate statistical methods was used to resolve a complex pool of large insert genomic sequences derived from Eel River Basin sediments. In silico pathway reconstruction of binned sequence data expanded the range of carbon and energy metabolism associated with AOM, identifying lineage-specific variation with respect to central metabolism, electron acceptors and C1 pathway components. To explore these pathways, liquid chromatography (LC) tandem mass spectrometry (MS/MS) will be used to identify peptides recovered directly from push core samples from the Eel River, Santa Barbara Basin and Saanich Inlet spanning vertical gradients of AOM. We will search for overlapping but not identical sets of expressed genes typically associated with methane production among the different ANME lineages. Using this profile information we will develop unambiguous biomarkers for ANME community structure and function and validate previous hypotheses regarding metabolic flux of methane-derived carbon. These data will in turn provide a mechanistic foundation for modeling the individual contributions of specific ANME lineages to the global carbon cycle.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2010-10-01
End Date
2013-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Hallam SJ, L Constan, YC Song, AD Norbeck, HM Brewer, and L Pasa-Tolic. 2010. "Molecular tools for investigating ANME population structure and function." In Methods in Enzymology. PNNL-SA-75404, Pacific Northwest National Laboratory, Richland, WA.