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Temperature-sensitive mutant rho-115 rho-RNA binary complexes, and stabilization by substrates and analogues
Molecular & General Genetics : MGG
|January 1, 1982
Summary
Mutant rho protein (rho-115) from Escherichia coli shows temperature-sensitive instability when binding RNA. Adenosine triphosphate (ATP) stabilizes these complexes, restoring normal function and suggesting ATP modulates rho-RNA interactions.
Area of Science:
- Molecular biology
- Biochemistry
- Enzymology
Background:
- Escherichia coli rho factor is an RNA-dependent ATPase crucial for transcription termination.
- Mutant rho-115 exhibits temperature-sensitive defects, impacting its RNA binding and ATPase activity.
Purpose of the Study:
- To elucidate the molecular basis of temperature sensitivity in mutant rho RNA-dependent ATPase.
- To investigate the role of ATP in stabilizing mutant rho-RNA complexes.
Main Methods:
- Investigated binding of wild-type and mutant rho (rho-115) to polyC using nitrocellulose filter retention assays.
- Assessed complex stability at varying temperatures (37°C and 45°C) with and without ATP, ATP analogues, or hydrolysis products.
Main Results:
- Mutant rho-115-polyC complexes showed decreased stability at elevated temperatures (45°C) compared to wild-type.
- ATP and its analogue beta-gamma methylene ATP stabilized mutant rho-polyC complexes at 45°C.
- ADP also stabilized complexes, but required higher concentrations than ATP; adenine, adenosine, AMP, and Pi had no effect.
Conclusions:
- Mutant rho-115 protein displays RNA-induced structural instability.
- ATP binding induces a conformational change, conferring a wild-type phenotype and stabilizing rho-115-RNA interactions.
- Findings support models of ATP-mediated modulation of rho protein's interaction with RNA.