Crystal structure of human prostatic acid phosphatase .
BACKGROUND
Prostatic acid phosphatase (hPAP) is a major product of the human prostate gland, yet its physiological substrate remains unknown.


METHODS
Human PAP, purified from semen, was crystallized using polyethylene glycol as the precipitant and its crystal structure was determined using X-ray diffraction. The structure was refined at 3.1 A resolution to R = 16% and R(free) = 27%.


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 sites. 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 mechanism proposed for the rat enzyme should be extended to the human enzyme without reservations. The crystallographic data allowed the correlation of attachment sites of N-linked carbohydrate chains with a given carbohydrate type. The carbohydrates of the protein produced in the prostate cells and in the baculovirus expression system appear to differ at the site of complex carbohydrates attachment.
Jakob
C G
CG
Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA.
Lewinski
K
K
Kuciel
R
R
Ostrowski
W
W
Lebioda
L
L
D000135:Acid Phosphatase / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D002241:Carbohydrates / Q000737:chemistry; D018360:Crystallography, X-Ray; D006031:Glycosylation; D006801:Humans; D008297:Male; D008958:Models, Molecular; D011467:Prostate / Q000201:enzymology*; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D012661:Semen / Q000201:enzymology
D002241:Carbohydrates; D000135:Acid Phosphatase