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The structure of trp RNA-binding attenuation protein
A A Antson1, J Otridge, A M Brzozowski
1Department of Chemistry, University of York, UK.
Nature
|April 20, 1995
Summary
The trp RNA-binding attenuation protein from Bacillus subtilis forms a unique beta-wheel structure. L-tryptophan binding induces conformational changes, enabling messenger RNA interaction for gene regulation.
Area of Science:
- Structural biology
- Molecular biology
- Biochemistry
Background:
- The trp RNA-binding attenuation protein regulates gene expression in Bacillus subtilis.
- Understanding its structure is crucial for elucidating its regulatory mechanism.
Purpose of the Study:
- To determine the high-resolution crystal structure of the trp RNA-binding attenuation protein.
- To investigate the structural basis of L-tryptophan binding and its effect on protein conformation.
- To understand how the protein interacts with its messenger RNA target.
Main Methods:
- X-ray crystallography at 1.8 A resolution.
- Structural analysis of protein-ligand interactions.
- Conformational change analysis.
Main Results:
- A novel beta-wheel structure formed by eleven subunits, stabilized by intersubunit beta-sheets, with a central hole.
- L-tryptophan binds in clefts between beta-sheets, inducing conformational changes in flexible residues (25-33 and 49-52).
- The protein-L-tryptophan complex appears to form a circular surface that binds eleven U/GAG repeats of the messenger RNA target.
Conclusions:
- The determined structure reveals a unique protein architecture for RNA binding and attenuation.
- L-tryptophan acts as an allosteric effector, modulating the protein's conformation for specific RNA recognition.
- This structural insight provides a molecular basis for transcriptional attenuation in Bacillus subtilis.