Crystallization and preliminary X-ray analysis of HCE-1, a hatching enzyme of medaka fish, Oryzias latipes.

The hatching enzyme of medaka fish, high choriolytic enzyme (HCE-1; MW = 22.7 kDa), was crystallized by the hanging-drop vapour-diffusion method using PEG 10 000 as the precipitant. The hatching enzyme is a metalloproteinase which is secreted from the embryo at the time of hatching. The crystals diffracted X-rays to beyond 1.34 A resolution using a synchrotron-radiation source. The crystals belonged to the monoclinic space group C2, with unit-cell parameters a = 99.0, b = 30.4, c = 79.6 A, beta = 123.6 degrees. The crystal contains one molecule in an asymmetric unit (VM = 2.2 A3 Da-1) and has a solvent content of 43.7%.