Using the Theozyme Model to Study the Dynamical Mechanism of the Post-Transition State Bifurcation Reaction by NgnD...

Area of Science:

• Biochemistry
• Chemical Dynamics
• Enzyme Catalysis

Background:

• Post-transition state bifurcation (PTSB) describes reactions where a single transition state leads to multiple distinct products.
• This phenomenon is crucial in biological and chemical systems, impacting reaction mechanisms and product distribution.
• The theozyme model offers a computationally efficient approach to study enzyme-catalyzed PTSB, preserving catalytic function by focusing on key active site residues.

Purpose of the Study:

• To investigate the dynamics and regulatory mechanisms of PTSB in the NgnD-catalyzed cycloaddition reaction.
• To elucidate the role of specific active site residues in determining product selectivity between [6 + 4] and [4 + 2] adducts.
• To understand how enzyme active site residues collectively control the direction of adduct formation.

Main Methods:

• Utilized theozyme modeling to computationally study the enzyme NgnD's catalytic process.
• Analyzed the potential energy surface and bond length distributions of the reaction.
• Examined interactions between the theozyme model and the ambimodal transition state.

Main Results:

• NgnD catalyzes a cycloaddition reaction producing both [6 + 4] and [4 + 2] adducts, with a preference for the [6 + 4] adduct.
• Identified key active site residues that influence the selectivity of adduct formation.
• Demonstrated how these residues contribute to the stabilization and direction of the transition state, impacting product outcomes.

Conclusions:

• The study elucidates the molecular basis for product selectivity in NgnD-catalyzed PTSB reactions.
• Key active site residues play a critical role in directing the reaction towards specific adducts.
• Theozyme modeling provides valuable insights into enzyme-mediated control of complex reaction pathways.