Purification, crystallization and preliminary X‐ray diffraction analysis of recombinant human neutrophil‐activating peptide 2 (rhNAP‐2)

Abstract

The potent activator and chemoattractant for human neutrophils, neutrophil‐activating peptide 2 (NAP‐2), has been cloned and expressed in Escherichia coli. The protein has been purified to homogeneity (> 98%) by a series of chromatographic techniques, including reversed phase HPLC. The biological activity of recombinant human NAP‐2 (rhNAP‐2), characterized by the induction of elastase release from human neutrophils, was found to be comparable to natural NAP‐2. rhNAP‐2 has been crystallized by the hanging drop vapor diffusion method. The crystals belong to space group P222 with unit cell dimensions of a = 30.8 Å, b = 39.5 Å and c = 95.3 Å. A packing density of 3.8 ų/Da with a solvent content of approximately 68% is obtained when one molecule per asymmetric unit is assumed. The crystals were shown to diffract to beyond 2.0 Å on a conventional X‐ray source. They are stable to X‐rays for several days and are thus suitable for high resolution structure determination.