Members of the Ras subfamily of small GTP-binding proteins have been shown to be promiscuous towards a variety of putative effector molecules such as the protein kinase c-Raf and the Ral-specific guanine nucleotide exchange factor (Ral-GEF). To address the question of specificity of interactions we have introduced the mutations E30D and K31E into Rap and show biochemically, by X-ray structure analysis and by transfection in vivo that the identical core effector region of Ras and Rap (residues 32-40) is responsible for molecular recognition, but that residues outside this region are responsible for the specificity of the interaction ...
Members of the Ras subfamily of small GTP-binding proteins have been shown to be promiscuous towards a variety of putative effector molecules such as the protein kinase c-Raf and the Ral-specific guanine nucleotide exchange factor (Ral-GEF). To address the question of specificity of interactions we have introduced the mutations E30D and K31E into Rap and show biochemically, by X-ray structure analysis and by transfection in vivo that the identical core effector region of Ras and Rap (residues 32-40) is responsible for molecular recognition, but that residues outside this region are responsible for the specificity of the interaction. The major determinant for the switch in specificity is the opposite charge of residue 31--Lys in Rap, Glu in Ras--which creates a favourable complementary interface for the Ras-Raf interaction.
Related Citations:
Quantitative Structure-Activity Analysis Correlating Ras/Raf Interaction in Vitro to Raf Activation in Vivo Block, C., Janknecht, R., Herrmann, C., Nassar, N., Wittinghofer, A. (1996) Nat Struct Biol 3: 244
Quantitative Analysis of the Complex between P21Ras and the Ras-Binding Domain of the Human Raf-1 Protein Kinase Herrmann, C., Martin, G.A., Wittinghofer, A. (1995) J Biol Chem 270: 2901
The 2.2 A Crystal Structure of the Ras-Binding Domain of the Serine/Threonine Kinase C-Raf1 in Complex with RAP1A and a GTP Analogue Nassar, N., Horn, G., Herrmann, C., Scherer, A., Mccormick, F., Wittinghofer, A. (1995) Nature 375: 554
Organizational Affiliation:
Max-Planck-Institut für molekulare Physiologie, Abteilung Strukturelle Biologie, Dortmund, Germany.
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