2BGR image
Entry Detail
PDB ID:
2BGR
Keywords:
Title:
Crystal structure of HIV-1 Tat derived nonapeptides Tat(1-9) bound to the active site of Dipeptidyl peptidase IV (CD26)
Biological Source:
PDB Version:
Deposition Date:
2005-01-04
Release Date:
2005-01-27
Method Details:
Experimental Method:
Resolution:
2.00 Å
R-Value Free:
0.20
R-Value Work:
0.16
R-Value Observed:
0.16
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:DIPEPTIDYL PEPTIDASE IV
Chain IDs:A, B
Chain Length:738
Number of Molecules:2
Biological Source:HOMO SAPIENS
Polymer Type:polypeptide(L)
Description:HIV-1 TAT PROTEIN DERIVED N-TERMINAL NONAPEPTIDE
Chain IDs:C (auth: Y), D (auth: Z)
Chain Length:9
Number of Molecules:2
Biological Source:HUMAN IMMUNODEFICIENCY VIRUS TYPE 1
Modified Residue
Compound ID Chain ID Parent Comp ID Details 2D Image
ASN A ASN GLYCOSYLATION SITE
Ligand Molecules
Primary Citation
Crystal Structures of HIV-1 Tat-Derived Nonapeptides Tat-(1-9) and Trp2-Tat-(1-9) Bound to the Active Site of Dipeptidyl-Peptidase Iv (Cd26)
J.Biol.Chem. 280 14911 ? (2005)
PMID: 15695814 DOI: 10.1074/JBC.M413400200

Abstact

CD26 or dipeptidyl-peptidase IV (DPPIV) is engaged in immune functions by co-stimulatory effects on activation and proliferation of T lymphocytes, binding to adenosine deaminase, and regulation of various chemokines and cytokines. DPPIV peptidase activity is inhibited by both Tat protein from human immunodeficiency virus (HIV)-1 and its N-terminal nonapeptide Tat-(1-9) with amino acid sequence MDPVDPNIE, suggesting that DPPIV mediates immunosuppressive effects of Tat protein. The 2.0- and 3.15-A resolution crystal structures of the binary complex between human DPPIV and nonapeptide Tat-(1-9) and the ternary complex between the variant MWPVDPNIE, called Trp(2)-Tat-(1-9), and DPPIV bound to adenosine deaminase show that Tat-(1-9) and Trp(2)-Tat-(1-9) are located in the active site of DPPIV. The interaction pattern of DPPIV with Trp(2)-Tat-(1-9) is tighter than that with Tat-(1-9), in agreement with inhibition constants (K(i)) of 2 x 10(-6) and 250 x 10(-6) m, respectively. Both peptides cannot be cleaved by DPPIV because the binding pockets of the N-terminal 2 residues are interchanged compared with natural substrates: the N-terminal methionine occupies the hydrophobic S1 pocket of DPPIV that normally accounts for substrate specificity by binding the penultimate residue. Because the N-terminal sequence of the thromboxane A2 receptor resembles the Trp(2)-Tat-(1-9) peptide, a possible interaction with DPPIV is postulated.

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