To provide information for the design of non-beta-lactam drugs which will bypass beta-lactam resistance mechanisms, we have begun an x-ray crystallographic study to establish the three-dimensional structure of E. coli D-alanine:D-alanine ligase, a cell wall synthesizing enzyme which is a potential drug target already well characterized biochemically and kinetically by other workers. From this D-amino acid ligase has evolved VanA, the newly-discovered enzyme responsible for an emerging enterococcal resistance to antibiotics of the vancomycin family. VanA is an altered ligase which has 45-52% sequence similarity with two DD-ligases we have crystallized. High-resolution crystallographic determination of the DD-ligase structure will therefore not only provide atomic-level information about a new target enzyme unique to bacteria, but will also provide a structure on which to build a three-dimensional model of the vancomycin resistance protein, which has so far been recalcitrant to x-ray structure analysis.
| Healy, V L; Lessard, I A; Roper, D I et al. (2000) Vancomycin resistance in enterococci: reprogramming of the D-ala-D-Ala ligases in bacterial peptidoglycan biosynthesis. Chem Biol 7:R109-19 |
| Fan, C; Park, I S; Walsh, C T et al. (1997) D-alanine:D-alanine ligase: phosphonate and phosphinate intermediates with wild type and the Y216F mutant. Biochemistry 36:2531-8 |
| Fan, C; Moews, P C; Shi, Y et al. (1995) A common fold for peptide synthetases cleaving ATP to ADP: glutathione synthetase and D-alanine:d-alanine ligase of Escherichia coli. Proc Natl Acad Sci U S A 92:1172-6 |
| Fan, C; Moews, P C; Walsh, C T et al. (1994) Vancomycin resistance: structure of D-alanine:D-alanine ligase at 2.3 A resolution. Science 266:439-43 |
