CRYSTALLIZATION AND PRELIMINARY-X-RAY CRYSTALLOGRAPHIC STUDIES OF UDP-N-ACETYLENOLPYRUVYLGLUCOSAMINE REDUCTASE

The overexpression and purification of the second enzyme in Escherichi a coli peptidoglycan biosynthesis, UDP-N-acetylenolpyruvylglucosamine reductase (MurB), provided sufficient protein to undertake crystalliza tion and X-ray crystallographic studies of the enzyme. MurB crystalliz es in 14-20% PEG 8000, 100 mM sodium cacodylate, pH 8.0, and 200 mM ca lcium acetate in the presence of its substrate UDP-N-acetylglucosamine enolpyruvate. Crystals of MurB belong to the tetragonal space group P 4(1)2(1)2 with a = b = 49.6 Angstrom, c = 263.2 Angstrom, and alpha = beta = gamma = 90 degrees at -160 degrees C and diffract to at least 2 .5 Angstrom. Screening for heavy atom derivatives has yielded a single site that is reactive with both methylmercury nitrate and Thimerosal.