1TK3

Crystal Structure Of Human Apo Dipeptidyl Peptidase IV/CD26

Summary for 1TK3

• Entry DOI: 10.2210/pdb1tk3/pdb
• Related: 1TKR 1TO7
• Descriptor: Dipeptidyl peptidase IV, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[alpha-L-fucopyranose-(1-6)]2-acetamido-2-deoxy-beta-D-glucopyranose, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (8 entities in total)
• Functional Keywords: alpha/beta hydrolase, beta-propeller, homodimer, hydrolase
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 2
• Total formula weight: 175182.11

Authors

Bjelke, J.R.,Christensen, J.,Branner, S.,Wagtmann, N.,Olsen, C.,Kanstrup, A.B.,Rasmussen, H.B. (deposition date: 2004-06-08, release date: 2004-07-06, Last modification date: 2024-11-06)

Primary citation

Bjelke, J.R.,Christensen, J.,Branner, S.,Wagtmann, N.,Olsen, C.,Kanstrup, A.B.,Rasmussen, H.B.
Tyrosine 547 Constitutes an Essential Part of the Catalytic Mechanism of Dipeptidyl Peptidase IV
J.Biol.Chem., 279:34691-34697, 2004

PubMed Abstract: Human dipeptidyl peptidase IV (DPP-IV) is a ubiquitously expressed type II transmembrane serine protease. It cleaves the penultimate positioned prolyl bonds at the N terminus of physiologically important peptides such as the incretin hormones glucagon-like peptide 1 and glucose-dependent insulinotropic peptide. In this study, we have characterized different active site mutants. The Y547F mutant as well as the catalytic triad mutants S630A, D708A, and H740L showed less than 1% wild type activity. X-ray crystal structure analysis of the Y547F mutant revealed no overall changes compared with wild type apoDPP-IV, except the ablation of the hydroxyl group of Tyr(547) and a water molecule positioned in close proximity to Tyr(547). To elucidate further the reaction mechanism, we determined the crystal structure of DPP-IV in complex with diisopropyl fluorophosphate, mimicking the tetrahedral intermediate. The kinetic and structural findings of the tyrosine residue are discussed in relation to the catalytic mechanism of DPP-IV and to the inhibitory mechanism of the 2-cyanopyrrolidine class of potent DPP-IV inhibitors, proposing an explanation for the specificity of this class of inhibitors for the S9b family among serine proteases.

PubMed: 15175333
DOI: 10.1074/jbc.M405400200

Experimental method

X-RAY DIFFRACTION (2 Å)