Guanosine nucleotide binding by highly purified Ha-ras-encoded p21 protein produced in Escherichia coli
| Autor: | Shigeko Yamazaki, Veeraswamy Manne, Hsiang-Fu Kung |
|---|---|
| Rok vydání: | 1984 |
| Předmět: |
Multidisciplinary
GTP' GDP binding Guanosine Pronase Oncogenes Hydrogen-Ion Concentration Molecular biology Guanosine Diphosphate Gene product chemistry.chemical_compound Kinetics GTP-binding protein regulators Biochemistry chemistry Guanosine diphosphate GTP-Binding Proteins Escherichia coli Magnesium Guanosine Triphosphate Cloning Molecular Magnesium ion Research Article |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America. 81(22) |
| ISSN: | 0027-8424 |
| Popis: | High-level expression of the p21 protein product of the BALB murine sarcoma virus v-ras gene (similar to the product of the Harvey murine sarcoma virus v-Ha-ras gene) has been reported recently, and highly purified preparations of this protein have been obtained. We used a nitrocellulose filter assay for measuring the binding of GDP and GTP to the purified protein. Previously p21 antibodies had been used to precipitate p21-guanosine nucleotide complexes from crude extracts containing the protein. Using the filter assay, we find that the v-Ha-ras gene product binds [3H]GDP stoichiometrically. The binding is time-dependent and is faster at 30 degrees C than at 0 degrees C. Optimum binding is obtained in the presence of dithiothreitol and magnesium ions and at pH 7.4. In terms of its GDP binding activity, p21 is heat stable and pronase sensitive. The dissociation constants (Kd) of p21 for [3H]GDP and [3H]GTP, determined by Scatchard analysis, are 6 X 10(-8) M and 2.5 X 10(-8) M, respectively. |
| Databáze: | OpenAIRE |
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