Purification and crystallization of the extracellular domain of human neutral endopeptidase (neprilysin) expressed in Pichia pastoris

Neutral endopeptidase (NEP) is a mammalian zinc metalloprotease involved in the inactivation of a wide variety of regulatory peptides such as enkephal ins and atrial natiuretic factor. The soluble extracellular domain of NEP ( sNEP) was expressed in the methylotrophic yeast Pichia pastoris. The protei n was purified to homogeneity and single crystals have been obtained. Enzym atic deglycosylation of the enzyme was essential for the production of crys tals suitable for X-ray analysis for both the NEP-phosphoramidon binary com plex and the apo enzyme.