Development of a solid-phase binding assay and identification of nonpeptide ligands for the FynB Src homology 2 domain

The nonreceptor tyrosine kinase FynB is known to be required in the inducti on of long-term potentiation (LTP), a cellular mechanism for learning and m emory. Ligands of the FynB SH2 domain as a possible FynB activator are, thu s, of great interest. In this study, a solid-phase ligand binding assay was established to meet the screening requirement of high-throughput and ease of use, and in an attempt to find the specific ligands for the FynB SH2 dom ain. This assay measures the competitive inhibition of the binding of the b iotinylated phosphopeptide (GGSETDDY*AEIID), derived from a binding sequenc e in human focal adhesion kinase, to the SH2 domain of FynB precoated as a glutathione S-transferase fusion protein on a solid-phase. Using this high- throughput screening method for SH2 ligands, a modest size of chemical libr ary was screened, and two non-peptide compounds, 4-acetamidobenzene sulfini c acid and 1-allylpyridinium 3-sulfonate, were identified by their strong b inding affinity to the FynB SH2 domain. This result demonstrates the feasib ility of the developed assay in high-throughput screening. Further studies on the molecular structures of the identified SH2-binding ligands will allo w presentation of specific models for ligand-domain complexes for improving the ligands and will help to develop a potential lead compound for improvi ng LTP. (C) 2002 Elsevier Science B.V. All rights reserved.