Modulating the Coupling Efficiency of P450 BM3 by Controlling Water Diffusion through Access Tunnel Engineering

Area of Science:

• Biocatalysis
• Enzyme Engineering
• Protein Chemistry

Background:

• Cytochromes P450 are vital enzymes for oxidation reactions across industries.
• Improving their catalytic coupling efficiency remains a significant challenge.
• Excess water near the active site is linked to reduced enzyme efficiency (uncoupling).

Purpose of the Study:

• To engineer the P450 BM3 enzyme from Bacillus megaterium.
• To control water diffusion into the active site via tunnel engineering.
• To enhance the enzyme's catalytic coupling efficiency.

Main Methods:

• Site-saturation mutagenesis of nine key residues in P450 BM3 access tunnels.
• Investigating variants to reduce water diffusion.
• Utilizing tunnel polarity analysis and molecular dynamics simulations.

Main Results:

• A variant (N319L/T411V/T436A) demonstrated improved coupling efficiency from 31.2% to 52.6%.
• Reduced water molecules around the active site correlated with higher coupling efficiency.
• Tunnel engineering effectively controlled water access.

Conclusions:

• Controlling water diffusion through tunnel engineering is a viable strategy to enhance P450 coupling efficiency.
• This approach offers valuable insights for optimizing biocatalysis.
• The engineered P450 variants show promise for industrial applications.