Proteome-Scale Analysis of Vertebrate Protein Thermoadaptation Modulated by Dynamic Allostery and Protein Solvation

Abstract

Abstract Despite large differences in behaviors and living conditions, vertebrate organisms share the great majority of proteins often with subtle differences in amino acid sequence. By comparing a set of substantially homologous proteins between model vertebrate organisms at a sub-proteome level, we discover a pattern of amino acid conservation and a shift in amino acid use, noticeably with an apparent distinction between homeotherms (warm-blooded species) and poikilotherms (cold-blooded species). Importantly, we establish a connection between the thermoadaptation of protein sequences manifest in the evolved proteins and two of their physical features: a change in their proteins dynamics and in their solvation. For poikilotherms such as frog and fish, the lower body temperature is expected to increase the association of proteins due to a decrease in protein dynamics and correspondingly lower entropy penalty on binding. In order to prevent overly-sticky protein association at low temperatures, we find that poikilotherms enhance the solvation of their proteins by favoring polar amino acids on their protein’s surface. This study unveils a general mechanism behind amino acid choices that constitute part of the thermoadaptation of vertebrate organisms at the molecular level.