Crystal structure of human prostatic acid phosphatase

BACKGROUND. Prostatic acid phosphatase (hPAP) is a major product of the hum an prostate gland, yet its physiological substrate remains unknown. METHODS. Human PAP, purified from semen, was crystallized using polyethylen e glycol as the precipitant and its crystal structure was determined using X-ray diffraction. The structure was refined at 3.1 Prostate 42:211-228, 20 00. (C) 2000 Wiley-Liss, Inc.Angstrom resolution to R = 16% and R(free) = 2 7%. RESULTS. The structure of hPAP is similar to that of other known histidine phosphatases, and the positions of its catalytic residues are conserved. N- Linked carbohydrates are present at each of the possible glycosylation site s. It appears that high-mannose chains are attached to Asn 62 and Asp 301, while complex chains are at Asn 188. CONCLUSIONS. The similarity of the three-dimensional structures of rat PAP and human PAP indicates that the mechanistic analyses of the catalytic mech anism proposed for the rat carbohydrate type. The carbohydrates of the prot ein produced in the prostate cells and in the baculovirus expression system appear to differ at the site of complex carbohydrates attachment. (C) 2000 Wiley-Liss, Inc.