Novel mechanism for temperature-independent transitions in flexible molecules: role of thermodynamic fluctuations

TL;DR

This paper proposes a new physical mechanism explaining temperature-independent molecular transitions, emphasizing the role of thermodynamic fluctuations and stochastic broadening, with implications for biological processes like receptor desensitization.

Contribution

It introduces a novel mechanism for temperature-independent transitions in molecules based on thermodynamic fluctuations affecting quasi-isoenergetic states.

Findings

Stochastic broadening dominates low-frequency vibrations at room temperature.

The mechanism explains temperature-independent reaction rates.

Application to P2X3 receptor desensitization in neurons.

Abstract

Novel physical mechanism is proposed for explanation of temperature-independent transition reactions in molecular systems. The mechanism becomes effective in the case of conformation transitions between quasi-isoenergetic molecular states. It is shown that at room temperatures, stochastic broadening of molecular energy levels predominates the energy of low frequency vibrations accompanying the transition. This leads to a cancellation of temperature dependence in the stochastically averaged rate constants. As an example, physical interpretation of temperature-independent onset of P2X_3 receptor desensitization in neuronal membranes is provided.