Document Type

Article

Publication Version

Published Version

Publication Date

11-2003

Journal or Book Title

Journal of the American Chemical Society

Volume

125

Issue

51

First Page

15706

Last Page

15707

DOI

10.1021/ja0375380

Abstract

The Src homology 2 (SH2) domain of interleukin-2 tyrosine kinase (Itk) binds two separate ligands:  a phosphotyrosine-containing peptide and the Itk Src homology 3 (SH3) domain. Binding specificity for these ligands is regulated via cis/trans isomerization of the Asn 286−Pro 287 imide bond in the Itk SH2 domain. In this study, we develop a novel method of analyzing chemical shift perturbation and cross-peak volumes to measure the affinities of both ligands for each SH2 conformer. We find that the cis imide bond containing SH2 conformer exhibits a 3.5-fold higher affinity for the Itk SH3 domain compared with binding of the trans conformer to the same ligand, while the trans conformer binds phosphopeptide with a 4-fold greater affinity than the cis-containing SH2 conformer. In addition to furthering the understanding of this system, the method presented here will be of general application in quantitatively determining the specificities of conformationally heterogeneous systems that use a molecular switch to regulate binding between multiple distinct ligands.

Comments

Reprinted (adapted) with permission from Journal of the American Chemical Society 125 (2003): 15706, doi:10.1021/ja0375380. Copyright 2003 American Chemical Society.

Rights

One-time permission is granted only for the use specified in your request. No additional uses are granted (such as derivative works or other editions). For any other uses, please submit a new request.

Copyright Owner

American Chemical Society

Language

en

File Format

application/pdf

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