Quantum entanglement shared in hydrogen bonds and its usage as a resource in molecular recognition

TL;DR

This paper investigates quantum entanglement in hydrogen bonds and its potential role as a resource in molecular recognition, suggesting it could provide biological systems with an evolutionary advantage beyond classical thermodynamics.

Contribution

It demonstrates that hydrogen bonds can sustain useful quantum entanglement and proposes their utilization in molecular recognition processes, including ligand discrimination.

Findings

Hydrogen bonds exhibit significant quantum entanglement in thermal states.

Entanglement can enable discrimination of multiple ligands using shared quantum resources.

Quantum entanglement may have played a role in the evolution of genetic machinery.

Abstract

Quantum tunneling events occurring through biochemical bonds are capable to generate quantum correlations between bonded systems, which in turn makes the conventional second law of thermodynamics approach insufficient to investigate these systems. This means that the utilization of these correlations in their biological functions could give an evolutionary advantage to biomolecules to an extent beyond the predictions of molecular biology that are generally based on the second law in its standard form. To explore this possibility, we first compare the tunneling assisted quantum entanglement shared in the ground states of covalent and hydrogen bonds. Only the latter appears to be useful from a quantum information point of view. Also, significant amounts of quantum entanglement can be found in the thermal state of hydrogen bond. Then, we focus on an illustrative example of ligand binding in which a receptor protein or an enzyme is restricted to recognize its ligands using the same set of proton-acceptors and donors residing on its binding site. In particular, we show that such a biomolecule can discriminate between $3^n - 1$ agonist ligands if it uses the entanglement shared in $n$ intermolecular hydrogen bonds as a resource in molecular recognition. Finally, we consider the molecular recognition events encountered in both the contemporary genetic machinery and its hypothetical primordial ancestor in pre-DNA world, and discuss whether there may have been a place for the utilization of quantum entanglement in the evolutionary history of this system.