CRYSTALLIZATION AND PRELIMINARY-X-RAY ANALYSIS OF GAMMA-GLUTAMYL-TRANSPEPTIDASE FROM ESCHERICHIA-COLI K-12

γ-Glutamyltranspeptidase (EC 2.3.2.2) from Escherichia coli K-12 has been purified and crystallized by means of vapor diffusion in hanging drops. Two kinds of crystals on cell dimensions were found for X-ray diffraction analysis, one from ammonium sulfate and the other from polyethylene glycol 6000 as precipitants. The crystals of the orthorhombic form grown in the pesence of 15% polyethylene glycol and 20 mM sodium acetate buffer were chosen for further analysis. The crystals belonged to space group P212121, with cell dimensions of a = 128.1, b = 129.9 and c = 79.2 Å, and two constitute an asymmetric unit. These crystals diffracted to 2.0 Å resolution and were suitable for X-ray crystallographic studies. © 1993 Academic Press Limited.