1w1i

From Proteopedia

Revision as of 17:39, 12 November 2007

CRYSTAL STRUCTURE OF DIPEPTIDYL PEPTIDASE IV (DPPIV OR CD26) IN COMPLEX WITH ADENOSINE DEAMINASE

Overview

Dipeptidyl-peptidase IV (DPPIV or CD26) is a homodimeric type II membrane, glycoprotein in which the two monomers are subdivided into a, beta-propeller domain and an alpha/beta-hydrolase domain. As dipeptidase, DPPIV modulates the activity of various biologically important peptides, and, in addition, DPPIV acts as a receptor for adenosine deaminase (ADA), thereby mediating co-stimulatory signals in T-lymphocytes. The 3.0-A, resolution crystal structure of the complex formed between human DPPIV and, bovine ADA presented here shows that each beta-propeller domain of the, DPPIV dimer binds one ADA. At the binding interface, two hydrophobic loops, protruding from the beta-propeller domain of DPPIV interact with two, hydrophilic and heavily charged alpha-helices of ADA, giving rise to the, highest percentage of charged residues involved in a protein-protein, contact reported thus far. Additionally, four glycosides linked to Asn229, of DPPIV bind to ADA. In the crystal structure of porcine DPPIV, the, observed tetramer formation was suggested to mediate epithelial and, lymphocyte cell-cell adhesion. ADA binding to DPPIV could regulate this, adhesion, as it would abolish tetramerization.

About this Structure

1W1I is a Protein complex structure of sequences from Bos taurus and Homo sapiens with NAG, NDG and ZN as ligands. Active as Dipeptidyl-peptidase IV, with EC number 3.4.14.5 Structure known Active Site: AC1. Full crystallographic information is available from OCA.

Reference

Crystal structure of CD26/dipeptidyl-peptidase IV in complex with adenosine deaminase reveals a highly amphiphilic interface., Weihofen WA, Liu J, Reutter W, Saenger W, Fan H, J Biol Chem. 2004 Oct 8;279(41):43330-5. Epub 2004 Jun 22. PMID:15213224

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