Crystallization and preliminary X-ray analysis of the complex of porcine pancreatic elastase and a hybrid squash inhibitor

A hybrid inhibitor consisting of the scaffold of a squash-type inhibitor and a specific inhibitory peptide optimized from the third domain of ovomucoid inhibitor from turkey against porcine pancreatic elastase was synthesized by peptide synthesis. The complex formed by this hybrid inhibitor and the porcine pancreatic elastase was crystallized using the hanging-drop method with citrate in the crystallization solution. The space group was determined to be P2₁2₁2₁, with unit-cell parameters a = 56.33, b = 56.44, c = 72.76 Å. A complete X-ray diffraction data set was collected under cryogenic conditions to 1.8 Å.