Szeltner_2002_J.Biol.Chem_277_42613

Reference

Title : Electrostatic effects and binding determinants in the catalysis of prolyl oligopeptidase. Site specific mutagenesis at the oxyanion binding site - Szeltner_2002_J.Biol.Chem_277_42613
Author(s) : Szeltner Z , Rea D , Renner V , Fulop V , Polgar L
Ref : Journal of Biological Chemistry , 277 :42613 , 2002
Abstract :

Prolyl oligopeptidase, a member of a new family of serine peptidases, plays an important role in memory disorders. Earlier x-ray crystallographic investigations indicated that stabilization of the tetrahedral transition state of the reaction involved hydrogen bond formation between the oxyanion of the tetrahedral intermediate and the OH group of Tyr(473). The contribution of the OH group was tested with the Y473F variant using various substrates. The charged succinyl-Gly-Pro-4-nitroanilide was hydrolyzed with a much lower k(cat)/K(m) compared with the neutral benzyloxycarbonyl-G1y-Pro-2-naphthylamide, although the binding modes of the two substrates were similar, as shown by x-ray crystallography. This suggested that electrostatic interactions between Arg(643) and the succinyl group competed with the productive binding mechanism. Unlike most enzyme reactions, catalysis by the wild-type enzyme exhibited positive activation entropy. In contrast, the activation entropy for the Y473F variant was negative, suggesting that the tyrosine OH group is involved in stabilizing both the transition state and the water shell at the active site. Importantly, Tyr(473) is also implicated in the formation of the enzyme-substrate complex. The nonlinear Arrhenius plot suggested a greater significance of the oxyanion binding site at physiological temperature. The results indicated that Tyr(473) was more needed at high pH, at high temperature, and with charged substrates exhibiting "internally competitive inhibition.

PubMedSearch : Szeltner_2002_J.Biol.Chem_277_42613
PubMedID: 12202494
Gene_locus related to this paper: pig-ppce

Related information

Inhibitor Sin-Gly-Pro    Z-Pro-Prolinal
Gene_locus Sin-Gly-Pro    Z-Pro-Prolinal    pig-ppce
Structure Sin-Gly-Pro    Z-Pro-Prolinal    pig-ppce    1H2W    1H2X    1H2Y    1H2Z

Citations formats

Szeltner Z, Rea D, Renner V, Fulop V, Polgar L (2002)
Electrostatic effects and binding determinants in the catalysis of prolyl oligopeptidase. Site specific mutagenesis at the oxyanion binding site
Journal of Biological Chemistry 277 :42613

Szeltner Z, Rea D, Renner V, Fulop V, Polgar L (2002)
Journal of Biological Chemistry 277 :42613