Core promoter information content correlates with optimal growth temperature

Ariel A Aptekmann,Alejandro D Nadra

doi:10.1038/s41598-018-19495-8

Abstract

The subtle mechanisms by which protein-DNA interactions remain functional across a wide range of temperatures are largely unknown. In this work, we manually curated available information relating fully sequenced archaeal genomes with organism growth temperatures. We built a motif that represents the core promoter of each species and calculated its information content. We then studied the relation between optimal growth temperature (OGT) and information content (IC) in the promoter region.We found a positive correlation between G + C content and OGT in tRNA regions and not in overall genome. Furthermore, we found that there is a positive correlation between information content and optimal growth temperatures in Archaea. This can’t be explained by an increased C+G composition nor by other obvious mechanisms. These findings suggest that increased information content could produce a positive fitness in organisms living at high temperatures. We suggest that molecular information theory may need to be adapted for hyperthermophiles.

Highlights

Every organism arises from a similar organism and lives in a physicochemical environment
Even though there exist some databases of archaea informing OGT9,10, to obtain a high degree of confidence in our data, we decided to curate our dataset by reviewing bibliography and existing databases
While there is a clear increase in 16 S Ribosomal RNA’s G + C content with temperature, a significant correlation was not observed among genome G + C content and optimal growth temperature (OGT) (Figure S1)

Summary

Introduction

Every organism arises from a similar organism and lives in a physicochemical environment. There is an essential biological process that has been the subject of several evolutionary and biophysical studies, transcription initiation, where a TATA box Binding Protein (TBP) interacts with its target site. The archaeal TBP family is ideally suited to study the evolutionary adaptation of a DNA binding protein in a wide range of temperatures. Far from being random, sequence variability is biologically relevant and is related to the underlying process of protein-DNA interaction which can be associated to an information content (IC). For each species we derived its TBP binding motif and calculated its information content This value was correlated with the reported OGT, obtaining a positive trend. We suggest that living temperature may affect protein-DNA recognition (either directly or by unknown mediators) and that it may be needed to be explicitly accounted in molecular information theory

Methods

Results

Conclusion