Crystallization and preliminary X-ray characterization of VanA from Enterococcus faecium BM4147: towards the molecular basis of bacterial resistance to the glycopeptide antibiotic vancomycin

A recombinant form of Enterococcus facieum BM4147 D-alanine-D-lactate ligas e (VanA) has been prepared and crystallized. VanA was found to crystallize only in the presence of a phosphinate inhibitor analogue of D-alanine-D-ala nine. The crystals grow in 40-45% ammonium sulfate, 0.1 M 3-(N-morpholino)- propanesulfonic acid pH 6.0 and reach dimensions of 0.4 x 0.2 x 0.1 mm. The crystals diffract to at least 2.5 Angstrom and are in the centred orthorho mbic space group C222(1), with unit-cell dimensions a = 123.2, b = 225.4, c = 72.4 Angstrom.