Characterization of an N-acetylmuramic acid/N-acetylglucosamine kinase of Clostridium acetobutylicum.

ABSTRACT: We report here the cloning and characterization of a cytoplasmic kinase of Clostridium acetobutylicum, named MurK (for murein sugar kinase). The enzyme has a unique specificity for both amino sugars of the bacterial cell wall, N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc), which are phosphorylated at the 6-hydroxyl group. Kinetic analyses revealed Km values of 190 and 127 μM for MurNAc and GlcNAc, respectively, and a kcat value (65.0 s(-1)) that was 1.5-fold higher for the latter substrate. Neither the non-N-acetylated forms of the cell wall sugars, i.e., glucosamine and/or muramic acid, nor epimeric hexoses or 1,6-anhydro-MurNAc were substrates for the enzyme. MurK displays low overall amino acid sequence identity (24%) with human GlcNAc kinase and is the first characteri

SUBMITTER: Reith J 

PROVIDER: S-EPMC3187400 | biostudies-literature | 2011 Oct

REPOSITORIES: biostudies-literature