Crystallization and preliminary X-ray analysis of ZHE1, a hatching enzyme from the zebrafish Danio rerio

The hatching enzyme of the zebrafish, ZHE1 (29.3 kDa), is a zinc metalloprotease that catalyzes digestion of the egg envelope (chorion). ZHE1 was heterologously expressed in Escherichia coli, purified and crystallized by the hanging-drop vapour-diffusion method using PEG 3350 as the precipitant. Two diffraction data sets with resolution ranges 50.0–1.80 and 50.0–1.14 Å were independently collected from two crystals and were merged to give a highly complete data set over the full resolution range 50.0–1.14 Å. The space group was assigned as primitive orthorhombic P2₁2₁2₁, with unit-cell parameters a = 32.9, b = 62.5, c = 87.4 Å. The crystal contained one ZHE1 molecule in the asymmetric unit.