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The Src SH2 domain interacts dynamically with the focal adhesion kinase binding site as demonstrated by paramagnetic nmr spectroscopy
Author(s) -
Lindfors Hanna E.,
Drijfhout Jan Wouter,
Ubbink Marcellus
Publication year - 2012
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1002/iub.1038
Subject(s) - sh2 domain , proto oncogene tyrosine protein kinase src , focal adhesion , peptide , chemistry , biophysics , binding site , tyrosine kinase , tyrosine , phosphorylation , nuclear magnetic resonance spectroscopy , sh3 domain , plasma protein binding , biochemistry , stereochemistry , signal transduction , biology
Abstract The interaction between the tyrosine kinases Src and focal adhesion kinase (FAK) is a key step in signaling processes from focal adhesions. The phosphorylated tyrosine residue 397 in FAK is able to bind the Src SH2 domain. To establish the extent of the FAK binding motif, the binding affinity of the SH2 domain for phosphorylated and unphosphorylated FAK‐derived peptides of increasing length was determined and compared with that of the internal Src SH2 binding site. It is shown that the FAK peptides have higher affinity than the internal binding site and that seven negative residues adjacent to the core SH2 binding motif increase the binding constant 30‐fold. A rigid spin‐label incorporated in the FAK peptides was used to establish on the basis of paramagnetic relaxation enhancement whether the peptide–protein complex is well defined. A large spread of the paramagnetic effects on the surface of the SH2 domain suggests that the peptide–protein complex exhibits dynamics, despite the high affinity of the peptide. The strong electrostatic interaction between the positive side of the SH2 domain and the negative peptide results in a high affinity but may also favor a dynamic interaction. © 2012 IUBMB IUBMB Life, 2012