The directional nature of hydrophobic interactions: Implications for the mechanism of molecular recognition

TL;DR

This paper investigates the directional dependence of hydrophobic interactions and proposes a hydrophobic driven model to explain molecular recognition mechanisms in water, supported by molecular dynamics simulations.

Contribution

It introduces a novel understanding of how hydrophobic interactions depend on orientation and proposes a new model for molecular recognition.

Findings

Hydrophobic interactions are orientation-dependent.

Short-range interactions strengthen as solutes approach.

A hydrophobic driven model explains specificity in water.

Abstract

Based on recent studies on hydrophobic interactions, it is devoted to investigate the directional nature of hydrophobic interactions. It means that the hydrophobic interactions are dependent on the relative orientations as the solutes tend to be aggregated in water. In H1w process, they are attracted to approach each other in the specific direction with lower energy barrier until their surfaces become contact. In H2s process, to maximize the hydrogen bondings of water, the solutes are aggregated in the specific direction to minimize the ratio of surface area to volume of them. Additionally, with decreasing the separation between them, the short-range interactions between the solutes become stronger. In addition, these can be demonstrated by the calculated potential of mean force (PMF) using molecular dynamics simulation. From this work, the hydrophobic driven model is proposed to understand the specificity and affinity of molecular recognition in water.