4o7p

Publication Abstract from PubMed

Mycobacterium tuberculosis (Mtb) uses maltose-1-phosphate to synthesize alpha-glucans that make up the major component of its outer capsular layer. Maltose kinase (MaK) catalyzes phosphorylation of maltose. The molecular basis for this phosphorylation is currently not understood. Here, we describe the first crystal structure of MtbMaK refined to 2.4 A resolution. The bi-modular architecture of MtbMaK reveals a remarkably unique N-lobe. An extended sheet protrudes into ligand binding pocket of an adjacent monomer and contributes residues critical for kinase activity. Structure of the complex of MtbMaK bound with maltose reveals that maltose binds in a shallow cavity of the C-lobe. Structural constraints permit phosphorylation of alpha-maltose only. Surprisingly, instead of a Gly-rich loop, MtbMaK employs 'EQS' loop to tether ATP. Notably, this loop is conserved across all MaK homologues. Structures of MtbMaK presented here unveil features that are markedly different from other kinases and support the scaffolding role proposed for this kinase.

Homotypic dimerization of a maltose kinase for molecular scaffolding.,Li J, Guan X, Shaw N, Chen W, Dong Y, Xu X, Li X, Rao Z Sci Rep. 2014 Sep 23;4:6418. doi: 10.1038/srep06418. PMID:25245657^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.