Computational Study of Molecular Mechanisms of Caffeine Actions

TL;DR

This study uses computer simulations to explore how caffeine interacts with adenosine receptors at the molecular level, revealing potential mechanisms for its effects on the nervous system.

Contribution

It provides the first detailed molecular-level analysis of caffeine binding to adenosine receptor fragments using energy minimization and Monte Carlo simulations.

Findings

Caffeine forms hydrogen bonds with amino acid residues in adenosine receptors.

Caffeine can block adenosine interaction sites without hydrogen bonding.

Deep energy minima suggest stable caffeine-receptor complexes.

Abstract

Caffeine (CAF) is one of the most widely and regularly consumed biologically active substances. We use computer simulation approach to the study of CAF activity by searching for its possible complexes with biopolymer fragments. The principal CAF target at physiologically important concentrations refers to adenosine receptors. It is a common opinion that CAF is a competitive antagonist of adenosine. At the first step to molecular level elucidation of CAF action, we have found a set of the minima of the interaction energy between CAF and the fragments of human A1 adenosine receptor. Molecular mechanics is the main method for the calculations of the energy of interactions between CAF and the biopolymer fragments. We use the Monte Carlo simulation to follow various mutual arrangements of CAF molecule near the receptor. It appears that the deepest energy minima refer to hydrogen-bond formation of CAF with amino acid residues involved in interactions with adenosine, its agonists and antagonists. The results suggest that the formation of such CAF-receptor complexes enforced by a close packing of CAF and the receptor fragments is the reason of CAF actions on nervous system. CAF can block the atomic groups of the adenosine repressors responsible for the interactions with adenosine, not necessary by the formation of H bonds with them, but simply hide these groups from the interactions with adenosine.