A Preliminary Description of the Crystal Structure of γ-Glutamyltranspeptidase from E. coli K-12

Abstract

The structure of GGT [EC 2. 3. 2. 2] from E. coli K-12 was studied at 3 Å resolution by X-ray crystallography. Initial protein phases were calculated using two kinds of Pb²⁺ derivatives. The phases were refined by non-crystallographic 2-fold symmetry electron density averaging combined with solvent flattening and histogram matching. The GGT molecule has overall dimensions of 60×50×40 Å There are two antiparallel β-pleated sheets consisting of 6 and 7 β-strands. The two β-sheets form a wall-like structure. Twelve short α-helices were detected, of which the maximum length appears to be four helix turns.