Identification of a unique Radical SAM methyltransferase required for the sp3-C-methylation of an arginine residue of methyl-coenzyme M reductase

• Published in: Scientific reports Vol. 8; no. 1; pp. 1 - 12
• Main Authors: Deobald, Darja, Adrian, Lorenz, Schöne, Christian, Rother, Michael, Layer, Gunhild
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 09-05-2018; Nature Publishing Group; Nature Portfolio
• Subjects: 45/70; 45/77; 631/326/26/2527; 631/45/612/1141; 631/45/612/1238; 82; 82/16; 82/29; 82/58; 82/83; Amino acids; Arginine; Biogas; Climate change; Coenzyme M; DNA methylation; Enzymes; Gene deletion; Global warming; Greenhouse gases; Humanities and Social Sciences; Methane; Methanogenesis; Methionine; Methylation; Methyltransferase; multidisciplinary; Reductase; Science; Science (multidisciplinary)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-25716-x

The biological formation of methane (methanogenesis) is a globally important process, which is exploited in biogas technology, but also contributes to global warming through the release of a potent greenhouse gas into the atmosphere. The last and methane-releasing step of methanogenesis is catalysed by the enzyme methyl-coenzyme M reductase (MCR), which carries several exceptional posttranslational amino acid modifications. Among these, a 5-C-(
S
)-methylarginine is located close to the active site of the enzyme. Here, we show that a unique Radical
S
-adenosyl-L-methionine (SAM) methyltransferase is required for the methylation of the arginine residue. The gene encoding the methyltransferase is currently annotated as “methanogenesis marker 10” whose function was unknown until now. The deletion of the methyltransferase gene
ma4551
in
Methanosarcina acetivorans
WWM1 leads to the production of an active MCR lacking the C-5-methylation of the respective arginine residue. The growth behaviour of the corresponding
M
.
acetivorans
mutant strain and the biophysical characterization of the isolated MCR indicate that the methylated arginine is important for MCR stability under stress conditions.