Efficient Sulfide Assimilation in Methanosarcina acetivorans is Mediated by the MA1715 Protein
Sponsor
This work, including the efforts of John J. Perona, was funded by National Aeronautics and Space Administration (NASA) (NNX15AP59G)
Published In
Journal of Bacteriology
Document Type
Citation
Publication Date
7-1-2016
Abstract
Conserved genes essential to sulfur assimilation and trafficking in aerobic organisms are missing in many methanogens, most of which inhabit highly sulfidic, anaerobic environmental niches. This suggests that methanogens possess distinct pathways for the synthesis of key metabolites and intermediates, including cysteine, homocysteine, and protein persulfide groups. Prior work identified a novel tRNA-dependent two-step pathway for cysteine biosynthesis and a new metabolic transformation by which sulfur is inserted into aspartate semialdehyde to produce homocysteine. Homocysteine biosynthesis requires two of the three proteins previously identified in our laboratory by a comprehensive bioinformatics approach. Here, we show that the third protein identified in silico, the ApbE-like protein COG2122, facilitates sulfide assimilation in Methanosarcina acetivorans. Knockout strains lacking the gene encoding COG2122 are severely impaired for growth when sulfide is provided as the sole sulfur source. However, rapid growth is recovered upon supplementation with cysteine, homocysteine, or cystathionine, suggesting that COG2122 is required for efficient biosynthesis of both cysteine and homocysteine. Deletion of the gene encoding COG2122 does not influence the extent of sulfur modifications in tRNA or the prevalence of iron-sulfur clusters, indicating that the function of COG2122 could be limited to sulfide assimilation for cysteine and homocysteine biosynthesis alone
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DOI
10.1128/JB.00141-16
Persistent Identifier
http://archives.pdx.edu/ds/psu/18848
Citation Details
Rauch, B. J., & Perona, J. J. (2016). Efficient Sulfide Assimilation in Methanosarcina acetivorans Is Mediated by the MA1715 Protein. Journal of Bacteriology,198(14), 1974–1983. http://doi.org/10.1128/JB.00141-16