Crystallization and preliminary X-ray analysis of the Escherichia coli UDP-MurNAc-tripeptide D-alanyl-D-alanine-adding enzyme (MurF)

Crystals of the Escherichia coli UDP-MurNAc-tripeptide D-Ala-D-Ala-adding p rotein (MurF), which catalyzes the formation of the last metabolite of the bacterial cell-wall building block, have been grown in hanging-drop vapor-d iffusion trials using PEG 8K as a precipitating agent. The crystals belong to hexagonal space group P6(1) or P6(5) with unit-cell dimensions a = b = 7 4, c = 425 Angstrom. The asymmetric unit contains two molecules, with a cry stal volume per protein mass (V-m) of 3.4 Angstrom(3) Da(-1) and a solvent content of about 64% by volume. A native data set to 2.8 Angstrom resolutio n has been obtained from a frozen crystal using a synchrotron X-ray source.