Thermodynamic constraints on kinetic proofreading in biosynthetic pathways

Area of Science:

• Biophysics
• Biochemistry
• Molecular Biology

Background:

• Kinetic proofreading is a biological mechanism to ensure molecular accuracy.
• Nucleoside triphosphate hydrolysis is central to many cellular processes requiring fidelity.

Purpose of the Study:

• To develop a quantitative theory for kinetic proofreading with multiple checking steps.
• To determine the relationship between free energy dissipation and error frequency.

Main Methods:

• Quantitative theoretical modeling of kinetic proofreading pathways.
• Analysis of systems with an arbitrary number of post-hydrolysis checking steps.

Main Results:

• Ultimate accuracy is limited by the displacement from equilibrium of nucleoside triphosphates.
• Multiple checking steps are more energy-efficient for achieving high accuracy than single steps.
• Equal contribution from each checking step optimizes accuracy and implies symmetrical rate constants.

Conclusions:

• The theory provides insights into optimizing biological accuracy and energy efficiency.
• Findings may explain discrepancies in amino acylation and mRNA translation fidelity.
• The study highlights the importance of enzyme kinetics and thermodynamics in molecular recognition.