Premium
Ras binding to a C‐terminal region of GAP
Author(s) -
Molloy David P.,
Owen Darerca,
Grand Roger J.A.
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00657-u
Subject(s) - gtpase , gtp' , mutant , gtpase activating protein , chemistry , binding site , peptide , small gtpase , biochemistry , stereochemistry , biophysics , microbiology and biotechnology , biology , g protein , receptor , signal transduction , enzyme , gene
Using fluorescence spectroscopy we have identified a binding region for Ras on the GTPase activating protein (GAP) lying within residues 715–753. A synthetic peptide Y922, corresponding to residues 716–753 of GAP binds to wild type Ras showing 3.3‐fold higher affinity for the GTP‐ over the GDP‐bound forms of Ras. Binding is stabilised by Mg 2+ , although Y922 does not stimulate the GTPase activity of Ras. Peptide binding to the Y32A and Y40F Ras mutants showed equal affinity for both GDP‐ and GTP‐bound forms, with binding to Y32A · GDP abolished in the absence of Mg 2+ . These results suggest that Y922 mimics the in vivo interactions shown by the intact p120 GAP protein and provide the first direct demonstration of Ras interaction with GAP in the region 715–753.