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Substrate binding to mononuclear metallo-beta-lactamase from Bacillus cereus
Matteo Dal Peraro1, Alejandro J Vila, Paolo Carloni
1International School for Advanced Studies, SISSA and INFM-DEMOCRITOS, Trieste, Italy.
Proteins
|January 30, 2004
Summary
Molecular dynamics simulations reveal how Bacillus cereus zinc-beta-lactamase binds cefotaxime. The enzyme forms a stable complex, positioning the antibiotic near the catalytic hydroxide for efficient hydrolysis.
Area of Science:
- Biochemistry
- Molecular Biology
- Enzymology
Background:
- Beta-lactamases are crucial enzymes in antibiotic resistance.
- Mononuclear zinc-beta-lactamases utilize a zinc ion in their active site for catalysis.
- Understanding substrate binding is key to developing new inhibitors.
Purpose of the Study:
- To investigate the binding mechanism of cefotaxime to Bacillus cereus mononuclear zinc-beta-lactamase.
- To elucidate the structural dynamics of the enzyme-substrate complex using computational methods.
Main Methods:
- Molecular dynamics (MD) simulations were employed.
- Simulations were based on a previously proposed hydrogen-bond pattern.
- Both the free enzyme and the enzyme-cefotaxime complex were simulated.
Main Results:
- The resting state of the enzyme showed agreement with crystallographic data.
- Cefotaxime adopted a stable orientation within the catalytic pocket on the nanosecond timescale.
- The beta-lactam ring remained intact and proximal to the zinc-bound hydroxide nucleophile.
Conclusions:
- A stable, productive enzyme-substrate complex is formed.
- The dynamics simulations provide insights into the catalytic mechanism of this zinc-beta-lactamase.
- This detailed understanding can inform the design of novel beta-lactamase inhibitors.