title: Structure of MurA (UDP-N-acetylglucosamine enolpyruvyl transferase) from Vibrio fischeri in complex with substrate UDP-N-acetylglucosamine and the drug fosfomycin.
abstract: The development of new antibiotics is necessitated by the rapid development of resistance to current therapies. UDP-N-acetylglucosamine enolpyruvyl transferase (MurA), which catalyzes the first committed step of bacterial peptidoglycan biosynthesis, is a prime candidate for therapeutic intervention. MurA is the target of the antibiotic fosfomycin, a natural product produced by Streptomyces. Despite possessing a high degree of sequence conservation with MurA enzymes from fosfomycin-susceptible organisms, recent microbiological studies suggest that MurA from Vibrio fischeri (VfiMurA) may confer fosfomycin resistance via a mechanism that is not yet understood. The crystal structure of VfiMurA in a ternary complex with the substrate UDP-N-acetylglucosamine (UNAG) and fosfomycin has been solved to a resolution of 1.93 Å. Fosfomycin is known to inhibit MurA by covalently binding to a highly conserved cysteine in the active site of the enzyme. A comparison of the title structure with the structure of fosfomycin-susceptible Haemophilus influenzae MurA (PDB entry 2rl2) revealed strikingly similar conformations of the mobile substrate-binding loop and clear electron density for a fosfomycin-cysteine adduct. Based on these results, there are no distinguishing sequence/structural features in VfiMurA that would translate to a diminished sensitivity to fosfomycin. However, VfiMurA is a robust crystallizer and shares high sequence identity with many clinically relevant bacterial pathogens. Thus, it would serve as an ideal system for use in the structure-guided optimization of new antibacterial agents.
authors.affiliation: Structural Biology, Trius Therapeutics, 6310 Nancy Ridge Drive, Suite 101, San Diego, CA 92008, USA.
authors.forename: D C
authors.initials: DC
authors.lastname: Bensen
authors.forename: S
authors.initials: S
authors.lastname: Rodriguez
authors.forename: J
authors.initials: J
authors.lastname: Nix
authors.forename: M L
authors.initials: ML
authors.lastname: Cunningham
authors.forename: L W
authors.initials: LW
authors.lastname: Tari
mesh_terms: D048908:Aliivibrio fischeri / Q000201:enzymology*; D019883:Alkyl and Aryl Transferases / Q000737:chemistry* / Q000378:metabolism; D005578:Fosfomycin / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D054730:Protein Interaction Domains and Motifs; D013379:Substrate Specificity; D014537:Uridine Diphosphate N-Acetylglucosamine / Q000737:chemistry* / Q000378:metabolism
chemical_list: D005578:Fosfomycin; D014537:Uridine Diphosphate N-Acetylglucosamine; D019883:Alkyl and Aryl Transferases; C022566:UDP-N-acetylglucosamine 1-carboxyvinyltransferase