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Interaction of the p85 subunit of PI 3‐kinase and its N‐terminal SH2 domain with a PDGF receptor phosphorylation site: structural features and analysis of conformational changes.
Author(s) -
Panayotou G.,
Bax B.,
Gout I.,
Federwisch M.,
Wroblowski B.,
Dhand R.,
Fry M.J.,
Blundell T.L.,
Wollmer A.,
Waterfield M.D.
Publication year - 1992
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1992.tb05524.x
Subject(s) - biology , protein subunit , phosphorylation , sh2 domain , domain (mathematical analysis) , biochemistry , platelet derived growth factor receptor , microbiology and biotechnology , receptor , proto oncogene tyrosine protein kinase src , gene , mathematical analysis , mathematics , growth factor
Circular dichroism and fluorescence spectroscopy were used to investigate the structure of the p85 alpha subunit of the PI 3‐kinase, a closely related p85 beta protein, and a recombinant SH2 domain‐containing fragment of p85 alpha. Significant spectral changes, indicative of a conformational change, were observed on formation of a complex with a 17 residue peptide containing a phosphorylated tyrosine residue. The sequence of this peptide is identical to the sequence surrounding Tyr751 in the kinase‐insert region of the platelet‐derived growth factor beta‐receptor (beta PDGFR). The rotational correlation times measured by fluorescence anisotropy decay indicated that phosphopeptide binding changed the shape of the SH2 domain‐containing fragment. The CD and fluorescence spectroscopy data support the secondary structure prediction based on sequence analysis and provide evidence for flexible linker regions between the various domains of the p85 proteins. The significance of these results for SH2 domain‐containing proteins is discussed.