Abstract
The biosynthetic pathway of peptidoglycan, an essential component of bacterial cell wall, is a well-recognized target for antibiotic development. Peptidoglycan precursors are synthesized in the bacterial cytosol by various enzymes including the ATP-hydrolyzing Mur ligases, which catalyze the stepwise addition of amino acids to a UDP-MurNAc precursor to yield UDP-MurNAc-pentapeptide. MurD catalyzes the addition of D-glutamic acid to UDP-MurNAc-L-Ala in the presence of ATP; structural and biochemical studies have suggested the binding of the substrates with an ordered kinetic mechanism in which ligand binding inevitably closes the active site. In this work, we challenge this assumption by reporting the crystal structures of intermediate forms of MurD either in the absence of ligands or in the presence of small molecules. A detailed analysis provides insight into the events that lead to the closure of MurD and reveals that minor structural modifications contribute to major overall conformation alterations. These novel insights will be instrumental in the development of new potential antibiotics designed to target the peptidoglycan biosynthetic pathway.
Highlights
The development of bacterial resistance to antibiotics worldwide is a phenomenon that urges the need to discover new antibacterial drugs
The biosynthetic pathway of peptidoglycan, a key component of the bacterial cell wall, is a tractable target since proteins that catalyze key reactions in the pathway can be targeted both by natural and synthetic antibiotics. [1,2,3,4] Peptidoglycan is a complex heteropolymer that consists of glycan chains cross-linked by short peptides
Structures of E. coli MurD solved by Bertrand and coworkers either in unbound form or in the presence of substrates or products suggest that ligand binding engenders a conformational movement of the C-terminal domain towards the center of the structure, leading to the closure of the enzyme. [9,10] Since the detailed knowledge of all of the forms of MurD is essential for optimal exploitation of this enzyme for potential antibiotic development, we initiated a study on the different conformations of E. coli MurD, initially by attempting to trap MurD in states that were distinct from those which had been previously described
Summary
The development of bacterial resistance to antibiotics worldwide is a phenomenon that urges the need to discover new antibacterial drugs. The biosynthetic pathway of peptidoglycan, a key component of the bacterial cell wall, is a tractable target since proteins that catalyze key reactions in the pathway can be targeted both by natural and synthetic antibiotics. [1,2,3,4] Peptidoglycan is a complex heteropolymer that consists of glycan chains cross-linked by short peptides. [5] The glycan chains are made up of alternating N-acetylglucosamine (GlcNAc) and PLOS ONE | DOI:10.1371/journal.pone.0152075. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The funder provided support in the form of salaries for MK, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
