Related Experiment Videos
Ligand-binding studies on light riboflavin synthase from Bacillus subtilis
European Journal of Biochemistry
|April 1, 1981
Summary
Bacillus subtilis riboflavin synthase binds two substrate analogues per subunit at different sites but only one product molecule. This binding mechanism involves nucleophilic attack on the substrate, forming a covalent hydrate.
Area of Science:
- Biochemistry
- Enzymology
- Structural Biology
Background:
- Bacillus subtilis light riboflavin synthase is a trimeric enzyme.
- It catalyzes a reaction involving 6,7-dimethyl-8-ribityllumazine.
Purpose of the Study:
- To investigate the binding of substrate and product analogues to Bacillus subtilis riboflavin synthase.
- To elucidate the binding stoichiometry and mechanism at the enzyme's active site.
Main Methods:
- Analytical ultracentrifugation
- Fluorescence titration
- Absorbance and difference absorbance measurements
Main Results:
- Each enzyme subunit binds two substrate analogue molecules at distinct sites.
- Each subunit binds one molecule of product analogues like riboflavin.
- Binding of 7-methyl-8-ribityllumazine suggests nucleophilic attack at C7, forming a covalent hydrate.
Conclusions:
- The enzyme exhibits differential binding stoichiometry for substrate and product analogues.
- A covalent intermediate is likely formed during substrate binding, indicating the reaction mechanism.