Fulop_2001_J.Biol.Chem_276_1262

Reference

Title : Structures of prolyl oligopeptidase substrate\/inhibitor complexes. Use of inhibitor binding for titration of the catalytic histidine residue - Fulop_2001_J.Biol.Chem_276_1262
Author(s) : Fulop V , Szeltner Z , Renner V , Polgar L
Ref : Journal of Biological Chemistry , 276 :1262 , 2001
Abstract :

Structure determination of the inactive S554A variant of prolyl oligopeptidase complexed with an octapeptide has shown that substrate binding is restricted to the P4-P2' region. In addition, it has revealed a hydrogen bond network of potential catalytic importance not detected in other serine peptidases. This involves a unique intramolecular hydrogen bond between the P1' amide and P2 carbonyl groups and another between the P2' amide and Nepsilon2 of the catalytic histidine 680 residue. It is argued that both hydrogen bonds promote proton transfer from the imidazolium ion to the leaving group. Another complex formed with the product-like inhibitor benzyloxycarbonyl-glycyl-proline, indicating that the carboxyl group of the inhibitor forms a hydrogen bond with the Nepsilon2 of His(680). Because a protonated histidine makes a stronger interaction with the carboxyl group, it offers a possibility of the determination of the real pK(a) of the catalytic histidine residue. This was found to be 6.25, lower than that of the well studied serine proteases. The new titration method gave a single pK(a) for prolyl oligopeptidase, whose reaction exhibited a complex pH dependence for k(cat)/K(m), and indicated that the observed pK(a) values are apparent. The procedure presented may be applicable for other serine peptidases.

PubMedSearch : Fulop_2001_J.Biol.Chem_276_1262
PubMedID: 11031266
Gene_locus related to this paper: pig-ppce

Related information

Mutation S554A_pig-ppce
Inhibitor S554A_pig-ppce    Z-Gly-Pro
Substrate S554A_pig-ppce    Z-Gly-Pro    Abz-GLY-PHE-GLY-PRO-PHE-GLY    Z-Gly-Pro-AMC
Gene_locus S554A_pig-ppce    Z-Gly-Pro    Abz-GLY-PHE-GLY-PRO-PHE-GLY    Z-Gly-Pro-AMC    pig-ppce
Structure S554A_pig-ppce    Z-Gly-Pro    Abz-GLY-PHE-GLY-PRO-PHE-GLY    Z-Gly-Pro-AMC    pig-ppce    1E8M    1E8N

Citations formats

Fulop V, Szeltner Z, Renner V, Polgar L (2001)
Structures of prolyl oligopeptidase substrate\/inhibitor complexes. Use of inhibitor binding for titration of the catalytic histidine residue
Journal of Biological Chemistry 276 :1262

Fulop V, Szeltner Z, Renner V, Polgar L (2001)
Journal of Biological Chemistry 276 :1262