AUTHOR=Kalyuzhanaya Marina G., Yang Song , Matsen Janet B., Konopka Michael , Green-Saxena Abigail , Clubb Justin , Sadilek Martin , Orphan Victoria J., Beck David 

TITLE=Global Molecular Analyses of Methane Metabolism in Methanotrophic Alphaproteobacterium, Methylosinus trichosporium OB3b. Part II. Metabolomics and 13C-Labeling Study

JOURNAL=Frontiers in Microbiology

VOLUME=4

YEAR=2013

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2013.00070

DOI=10.3389/fmicb.2013.00070

ISSN=1664-302X

ABSTRACT=<p>In this work we use metabolomics and <sup>13</sup>C-labeling data to refine central metabolic pathways for methane utilization in <italic>Methylosinus trichosporium</italic> OB3b, a model alphaproteobacterial methanotrophic bacterium. We demonstrate here that similar to non-methane utilizing methylotrophic alphaproteobacteria the core metabolism of the microbe is represented by several tightly connected metabolic cycles, such as the serine pathway, the ethylmalonyl-CoA (EMC) pathway, and the citric acid (TCA) cycle. Both <italic>in silico</italic> estimations and stable isotope labeling experiments combined with single cell (NanoSIMS) and bulk biomass analyses indicate that a significantly larger portion of the cell carbon (over 60%) is derived from CO<sub>2</sub> in this methanotroph. Our<sup>13</sup> C-labeling studies revealed an unusual topology of the assimilatory network in which phosph(enol) pyruvate/pyruvate interconversions are key metabolic switches. A set of additional pathways for carbon fixation are identified and discussed.</p>