C-terminal truncation of p21H preserves crucial kinetic and structural properties.
The human c-Ha-ras protooncogene product p21C was truncated at the C terminus by 23 amino acids. The resulting G-binding domain, p21 (1-166) = p21C', can be crystallized as a complex with the slowly hydrolyzing GTP analogues guanosin-5'-[beta,gamma-imido]triphosphate, guanosin-5'-[beta,gamma-methylene]triphosphate, and guanosin-5'-O-(3-thiotriphosphate). We show here that this protein has biochemical properties very similar to those of the intact protein. Activating mutations in position 12 (Gly12----Val; Gly12----Arg) have the same effect on the properties of the truncated protein as on intact protein. Nuclear magnetic resonance (NMR) measurements show no apparent effect of the C-terminal deletion on the solution structure of p21. This suggests that neither the structure of the G-binding domain nor any of its biochemical properties are markedly influenced by the truncation.
John
J
J
Max-Planck-Institut für Medizinische Forschung, Abteilung Biophysik, Heidelberg, Federal Republic of Germany.
Schlichting
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I
Schiltz
E
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Rösch
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P
Wittinghofer
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A
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002850:Chromatography, Gel; D004926:Escherichia coli / Q000235:genetics; D019204:GTP-Binding Proteins / Q000378:metabolism; D005822:Genetic Vectors; D006801:Humans; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D009154:Mutation; D010673:Pheochromocytoma / Q000473:pathology; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D013329:Structure-Activity Relationship
D011518:Proto-Oncogene Proteins; D019204:GTP-Binding Proteins