Physical constraints and functional plasticity of cellulases

Area of Science:

• Biocatalysis
• Enzyme kinetics
• Protein engineering

Background:

• Enzyme catalysis at interfaces is crucial but poorly understood.
• Lack of experimental data hinders progress in interfacial enzyme catalysis.
• Cellulases are vital enzymes in nature and industry.

Purpose of the Study:

• To investigate the kinetic properties of cellulases at interfaces.
• To identify fundamental relationships governing cellulase activity.
• To explore potential for in silico enzyme design.

Main Methods:

• Production and kinetic characterization of 83 diverse cellulases.
• Analysis of substrate binding strength and activation barriers.
• Identification of linear free energy relationships (LFERs).

Main Results:

• A consistent linear free energy relationship (LFER) was observed across diverse cellulases.
• This LFER correlates substrate binding strength with the activation energy barrier.
• Enzyme structure and mechanism did not negate the observed scaling.

Conclusions:

• The LFER reflects fundamental physical constraints of the hydrolysis process.
• Evolutionary pressures may have optimized cellulase phenotypes along this relationship.
• Cellulase activity can be predicted from substrate binding, facilitating enzyme design and selection.