Crystal Structure of MraY, an Essential Membrane Enzyme for Bacterial Cell Wall Synthesis

Abstract

The Phospho-MurNAc-pentapeptide translocase (MraY) is a prokaryotic membrane-spanning enzyme involved in an essential process of peptidoglycan synthesis: transfer the precursor phosphor-MurNAc-pentapeptide to carrier lipid undecaprenyl phosphate. MraY belongs to a subfamily of the polyprenyl-phosphate N-acetyl hexosamine 1-phosphate transferase (PNPT) superfamily whose members are involved in various biological processes including eukaryotic N-linked glycosylation. MraY has been a target for antibiotics development for its essentiality and specificity in bacteria. Therefore atomic structure of MraY can provides valuable mechanistic information that can aid development of new antibiotics. We report the crystal structure of MraY from Aquifex aeolicus (MraYAA), the first structure of the PNPT superfamily, at 3.3 Å resolution. The crystal structure, together with crystallographic and functional studies, reveals the architecture of MraYAA, the location of Mg2+ at the active site and the putative binding sites of both substrates. Our crystallographic studies provide insights into the mechanism of how MraY attaches a building block of peptidoglycan to a carrier lipid.