Development of a tertiary-structure model of the C-terminal domain of DPP IV

Abstract

Based on the recently published structure of prolyl oligopeptidase (POP) a model of the C-terminal part of dipeptidyl peptidase IV (DPP IV) which contains the active site has been developed. The structure of the model of DPP IV shows considerable similarity to the structure of POP particularly in the active site. A hydrophobic pocket (TyT666, Tyr670, Tyr 631, Va1556) forms the S1-binding site for recognition of proline. Tyr547 may stabilise the oxyanion formed in the tetrahedral intermediates by a strong hydrogen bond. The positively charged N-terminus of ligands of DPP IV is recognised by forming a salt bridge with the acidic side chain Glu668. A second hydrophobic pocket (S2′ to S5′) may represent an important binding site for HIV-1 Tat-protein derivatives, chemokines and others.