The molecular basis of vancomycin resistance in clinically relevant Enterococci: Crystal structure of d -alanyl- d -lactate ligase (VanA)

The molecular basis of vancomycin resistance in clinically relevant Enterococci: Crystal structure of d-alanyl-d-lactate ligase (VanA)

York Structural Biology Laboratory, Department of Chemistry, The University of York, Heslington, York YO10 5DD, United Kingdom

Edited by Christopher T. Walsh, Harvard Medical School, Boston, MA, and approved May 17, 2000 (received for review March 16, 2000)

Abstract

d-alanine-d-lactate ligase from Enterococcus faecium BM4147 is directly responsible for the biosynthesis of alternate cell-wall precursors in bacteria, which are resistant to the glycopeptide antibiotic vancomycin. The crystal structure has been determined with data extending to 2.5-Å resolution. This structure shows that the active site has unexpected interactions and is distinct from previous models for d-alanyl-d-lactate ligase mechanistic studies. It appears that the preference of the enzyme for lactate as a ligand over d-alanine could be mediated by electrostatic effects and/or a hydrogen-bonding network, which principally involve His-244. The structure of d-alanyl-d-lactate ligase provides a revised interpretation of the molecular events that lead to vancomycin resistance.

x-ray crystal structure

Footnotes

↵ * To whom reprint requests should be addressed. E-mail: roper{at}ysbl.york.ac.uk.
↵ † D.I.R. and T.H. contributed equally to this work.
This paper was submitted directly (Track II) to the PNAS office.
Data deposition: The atomic coordinates have been deposited in the Protein Data Bank, www.rcsb.org (PDB ID code 1E4E).
Article published online before print: Proc. Natl. Acad. Sci. USA, 10.1073/pnas.150116497.
Article and publication date are at www.pnas.org/cgi/doi/10.1073/pnas.150116497
Abbreviations:

d-Ala,

d-alanine;

d-Lac,

d-lactate;

DdlB,

E. coli d-Ala-d-Ala ligase;

VanA,

E. faecium BM4147 d-Ala-d-Lac ligase