InterPro domain: IPR036112

Methanogenic archaea produce methane via the anaerobic reduction of acetate or single carbon compounds [ 1 ]. Coenzyme M (CoM; 2-mercaptoethanesulphonic acid) serves as the terminal methyl carrier for this process. Previously thought to be unique to methanogenic archaea, CoM has also been found in methylotrophic bacteria.

Biosynthesis of CoM begins with the Michael addition of sulphite to phosphoenolpyruvate, forming 2-phospho-3-sulpholactate (PSL). This reaction is catalyzed by members of this family, PSL synthase (ComA) [ 2 ]. Subsequently, PSL is dephosphorylated by phosphosulpholactate phosphatase (ComB) to form 3-sulpholactate [ 3 ], which is then converted to 3-sulphopyruvate by L-sulpholactate dehydrogenase (ComC; 1.1.1.272 ) [ 4 ]. Sulphopyruvate decarboxylase (ComDE; 4.1.1.79 ) converts 3-sulphopyruvate to sulphoacetaldehyde [ 5 ]. Reductive thiolation of sulphoacetaldehyde is the final step.

This entry also includes some proteins from plants and fungi, such as HEAT-STRESS-ASSOCIATED 32 from Arabidopsis [ 6 ].

The ComA structure has a TIM beta/alpha-barrel fold with a parallel beta-sheet.

1. Redox-driven proton translocation in methanogenic Archaea. Cell. Mol. Life Sci. 59, 1513-33
2. Identification of coenzyme M biosynthetic phosphosulfolactate synthase: a new family of sulfonate-biosynthesizing enzymes. J. Biol. Chem. 277, 13421-9
3. Identification of coenzyme M biosynthetic 2-phosphosulfolactate phosphatase. A member of a new class of Mg(2+)-dependent acid phosphatases. Eur. J. Biochem. 268, 5176-88
4. Identification of an archaeal 2-hydroxy acid dehydrogenase catalyzing reactions involved in coenzyme biosynthesis in methanoarchaea. J. Bacteriol. 182, 3688-92
5. Identification of the gene encoding sulfopyruvate decarboxylase, an enzyme involved in biosynthesis of coenzyme M. J. Bacteriol. 182, 4862-7
6. Interplay between heat shock proteins HSP101 and HSA32 prolongs heat acclimation memory posttranscriptionally in Arabidopsis. Plant Physiol. 161, 2075-84