Dataset Information

The fungal product terreic acid is a covalent inhibitor of the bacterial cell wall biosynthetic enzyme UDP-N-acetylglucosamine 1-carboxyvinyltransferase (MurA) .

ABSTRACT: Terreic acid is a metabolite with antibiotic properties produced by the fungus Aspergillus terreus. We found that terreic acid is a covalent inhibitor of the bacterial cell wall biosynthetic enzyme MurA from Enterobacter cloacae and Escherichia coli in vitro. The crystal structure of the MurA dead-end complex with terreic acid revealed that the quinine ring is covalently attached to the thiol group of Cys115, the molecular target of the antibiotic fosfomycin. Kinetic characterization established that the inactivation requires the presence of substrate UNAG (UDP-N-acetylglucosamine), proceeding with an inactivation rate constant k(inact) of 130 M(-1) s(-1). Although the mechanisms of inactivation are similar, fosfomycin is approximately 50 times more potent than terreic acid, and the structural consequences of covalent modification by these two inhibitors are fundamentally different. The MurA-fosfomycin complex exists in the closed enzyme conformation, with the Cys115-fosfomycin adduct buried in the active site. In contrast, the dead-end complex with terreic acid is open, is free of UNAG, and has the Cys115-terreic acid adduct solvent-exposed. It appears that terreic acid reacts with Cys115 in the closed, binary state of the enzyme, but that the resulting Cys115-terreic acid adduct imposes steric clashes in the active site. As a consequence, the loop containing Cys115 rearranges, the enzyme opens, and UNAG is released. The differential kinetic and structural characteristics of MurA inactivation by terreic acid and fosfomycin reflect the importance of noncovalent binding potential, even for covalent inhibitors, in ensuring inactivation efficiency and specificity.

SUBMITTER: Han H

PROVIDER: S-EPMC2884014 | biostudies-literature | 2010 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The fungal product terreic acid is a covalent inhibitor of the bacterial cell wall biosynthetic enzyme UDP-N-acetylglucosamine 1-carboxyvinyltransferase (MurA) .

Han Huijong H Yang Yan Y Olesen Sanne H SH Becker Andreas A Betzi Stephane S Schönbrunn Ernst E

Biochemistry 20100501 19

Terreic acid is a metabolite with antibiotic properties produced by the fungus Aspergillus terreus. We found that terreic acid is a covalent inhibitor of the bacterial cell wall biosynthetic enzyme MurA from Enterobacter cloacae and Escherichia coli in vitro. The crystal structure of the MurA dead-end complex with terreic acid revealed that the quinine ring is covalently attached to the thiol group of Cys115, the molecular target of the antibiotic fosfomycin. Kinetic characterization established ...[more]

PMID: 20392080

Similar Datasets

Project description:Organisms of Chlamydia spp. are obligate intracellular, gram-negative bacteria with a dimorphic developmental cycle that takes place entirely within a membrane-bound vacuole termed an inclusion. The chlamydial anomaly refers to the fact that cell wall-active antibiotics inhibit Chlamydia growth and peptidoglycan (PG) synthesis genes are present in the genome, yet there is no biochemical evidence for synthesis of PG. In this work, we undertook a genetics-based approach to reevaluate the chlamydial anomaly by characterizing MurA, a UDP-N-acetylglucosamine enolpyruvyl transferase that catalyzes the first committed step of PG synthesis. The murA gene from Chlamydia trachomatis serovar L2 was cloned and placed under the control of the arabinose-inducible, glucose-repressible ara promoter and transformed into Escherichia coli. After transduction of a lethal DeltamurA mutation into the strain, viability of the E. coli strain became dependent upon expression of the C. trachomatis murA. DNA sequence analysis of murA from C. trachomatis predicted a cysteine-to-aspartate change in a key residue within the active site of MurA. In E. coli, the same mutation has previously been shown to cause resistance to fosfomycin, a potent antibiotic that specifically targets MurA. In vitro activity of the chlamydial MurA was resistant to high levels of fosfomycin. Growth of C. trachomatis was also resistant to fosfomycin. Moreover, fosfomycin resistance was imparted to the E. coli strain expressing the chlamydial murA. Conversion of C. trachomatis elementary bodies to reticulate bodies and cell division are correlated with expression of murA mRNA. mRNA from murB, the second enzymatic reaction in the PG pathway, was also detected during C. trachomatis infection. Our findings, as well as work from other groups, suggest that a functional PG pathway exists in Chlamydia spp. We propose that chlamydial PG is essential for progression through the developmental cycle as well as for cell division. Elucidating the existence of PG in Chlamydia spp. is of significance for the development of novel antibiotics targeting the chlamydial cell wall.

Dataset Information

The fungal product terreic acid is a covalent inhibitor of the bacterial cell wall biosynthetic enzyme UDP-N-acetylglucosamine 1-carboxyvinyltransferase (MurA) .

Publications

The fungal product terreic acid is a covalent inhibitor of the bacterial cell wall biosynthetic enzyme UDP-N-acetylglucosamine 1-carboxyvinyltransferase (MurA) .

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets