Energetic aspects of intramolecular coupling between the nucleotide binding site and the distal switch II region of the yeast RAS2 protein.
We have studied the interaction of the yeast RAS2 protein with guanine nucleotides using energetic parameters for the dissociation of RAS.nucleotide complexes. The results indicated that a Gly-->Ser substitution at position 82 led to an altered interaction with GppNHp and, to a lesser extent, also with GDP. It was also possible to conclude that structural perturbation of Gly82 can stimulate nucleotide release by decreasing the energetic barrier for nucleotide dissociation. This, together with the observation that residues 80 and 81 are involved in the response of RAS to nucleotide exchange factors without affecting GDP binding per se, suggests a potential mechanism for exchange factor-stimulated GDP release.
Dipartimento di Biochimica e Biotecnologie Mediche, Università di Napoli Federico II, Italy.
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D001665:Binding Sites; D004926:Escherichia coli; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism; D005998:Glycine; D006150:Guanine Nucleotides / Q000378:metabolism*; D006153:Guanosine Diphosphate / Q000378:metabolism; D006165:Guanylyl Imidodiphosphate / Q000378:metabolism; D011994:Recombinant Proteins; D012441:Saccharomyces cerevisiae / Q000737:chemistry*; D029701:Saccharomyces cerevisiae Proteins; D012694:Serine; D013329:Structure-Activity Relationship; D013696:Temperature; D013816:Thermodynamics; D018631:ras Proteins
D005656:Fungal Proteins; D006150:Guanine Nucleotides; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D006153:Guanosine Diphosphate; D006165:Guanylyl Imidodiphosphate; D012694:Serine; D019204:GTP-Binding Proteins; C489015:RAS2 protein, S cerevisiae; D018631:ras Proteins; D005998:Glycine