Structure of glutaminyl cyclase from Drosophila melanogaster in space group I 4

The structure of ligand‐free glutaminyl cyclase (QC) from Drosophila melanogaster ( Dm QC) has been determined in a novel crystal form. The protein crystallized in space group I 4, with unit‐cell parameters a = b = 122.3, c  = 72.7 Å. The crystal diffracted to a resolution of 2 Å at the home source. The structure was solved by molecular replacement and was refined to an R factor of 0.169. Dm QC exhibits a typical α/β‐hydrolase fold. The electron density of three monosaccharides could be localized. The accessibility of the active site will facilitate structural studies of novel inhibitor‐binding modes.