J Biol Chem, Vol. 273, Issue 46, 30406-30409, November 13, 1998
Structural Origins of L(+)-Tartrate Inhibition of
Human Prostatic Acid Phosphatase
Michael W.
LaCount,
George
Handy, and
Lukasz
Lebioda
From the Department of Chemistry and Biochemistry, University of
South Carolina, Columbia, South Carolina 29208
Acid phosphatase activity in the blood serum is
usually separated into tartrate-resistant and tartrate-refractory,
which is reported as the prostatic acid phosphatase level. Human
prostatic acid phosphatase crystals soaked in
N-propyl-L-tartramate were used to collect
x-ray diffraction data to 2.9 Å resolution under cryogenic conditions.
Positive difference electron density, corresponding to the inhibitor,
was found. The quality of the electron density maps clearly shows the
orientation of the carboxylate and N-propyl-substituted amide groups. The hydroxyl group attached to C3 forms two crucial hydrogen bonds with Arg-79 and His-257. Previous crystallographic studies compiled on the tartrate-rat prostatic acid phosphatase binary
complex (Lindqvist, Y., Schneider, G., and Vihko, P. (1993) J. Biol. Chem. 268, 20744-20746)
erroneously positioned D-tartrate into the active site.
Modeling studies have shown that the C3 hydroxyl group on the
D(
)-stereoisomer of tartrate, which does not
significantly inhibit prostatic acid phosphatase, does not form strong
hydrogen bonds with Arg-79 or His-257. The structure of human prostatic
acid phosphatase, noncovalently bound in
N-propyl-L-tartramate, is used to develop
inhibitors with higher specificity and potency than
L(+)-tartrate.
Copyright © 1998 by The American Society for Biochemistry and Molecular Biology, Inc.