Abstract
The thermodynamic contribution of a stacking interaction between Tyr85 in MS2 coat protein and a single-stranded pyrimidine in its RNA binding site has been examined. Mutation of Tyr85 to Phe, His, Cys, Ser and Ala decreased the RNA affinity by 1-3 kcal/mol under standard binding conditions. Since the Phe, His and Cys 85 proteins formed UV photocrosslinks with iodouracil-containing RNA at the same rate as the wild-type protein, the mutant proteins interact with RNA in a similar manner. The pH dependence of K(D) for the Phe and His proteins differs substantially from the wild-type protein, suggesting that the titration of position 85 contributes substantially to the binding properties. Experiments with specifically substituted phosphorothioate RNAs confirm a hydrogen bond between the hydroxyl group of tyrosine and a phosphate predicted by the crystal structure.
Original language | English (US) |
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Pages (from-to) | 6847-6853 |
Number of pages | 7 |
Journal | EMBO Journal |
Volume | 15 |
Issue number | 24 |
DOIs | |
State | Published - 1996 |
Keywords
- Phosphorothioates
- Photocrosslinking
- RNA-protein interactions
ASJC Scopus subject areas
- General Neuroscience
- Molecular Biology
- General Biochemistry, Genetics and Molecular Biology
- General Immunology and Microbiology