src homology 2

Src homology 2 (SH2) and Src homology 3 (SH3) are the two noncatalytic domains of Src family tyrosine kinases which has similar structural arrangement. SH2 is approximately 100 amino acids long domain contains two ? helices and seven ? strands. As well as SH3, a smaller domain of about 60 amino acids residues, characterized by a ?-barrel fold consists of five or six ?-strands arranged as two tightly packed anti-parallel ? sheets, short helices may be contained at the linker regions. Both SH2 and SH3 can be found in a variety of signaling molecules, owning to the role of them in kinase regulation, SH2 and SH3 and their ligands have become important signal transduction targets for drug discovery.