InterPro domain: IPR005238

2-phosphosulpholactate phosphatase (ComB; 3.1.3.71 ) is a magnesium-dependent acid phosphatase that catalyzes the second step in coenzyme M (CoM; 2-mercaptoethanesulphonic acid) biosynthesis, namely, the hydrolysis of (2R)-2-phospho-3-sulpholactate to yield (2R)-3-sulpholactate and phosphate. CoM is an essential cofactor that acts as the terminal methyl carrier in methanogenesis [ 1 ]. CoM has also a role in the bacterial pathway of aliphatic epoxide carboxylation [ 2 ]. Homologues of ComB have been identified in all available cyanobacterial genome sequences and in genomes from phylogenetically diverse bacteria and archaea. However, many of these organisms lack homologues of other CoM biosynthetic genes.

ComB has a complex alpha/beta topology. The monomer is composed of two domains thought to be related by a common ancestral gene, plus a C-terminal helical and beta-hairpin region [ 3 ].

1. 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
2. A role for coenzyme M (2-mercaptoethanesulfonic acid) in a bacterial pathway of aliphatic epoxide carboxylation. Proc. Natl. Acad. Sci. U.S.A. 96, 8432-7
3. Crystal structure of 2-phosphosulfolactate phosphatase (ComB) from Clostridium acetobutylicum at 2.6 A resolution reveals a new fold with a novel active site. Proteins 65, 771-6