Analysis of structural requirements for thermo-adaptation from orthologs in microbial genomes

Gao, Junxiang; Wang, Wei

Analysis of structural requirements for thermo-adaptation from orthologs in microbial genomes

2012

Gao, Junxiang | Wang, Wei

A comprehensive survey was carried out to identify orthologs of proteins from 526 bacterial and archaeal genomes, with the aim of investigating the mechanism of thermal adaptation of protein sequences. A large number of orthologs were distributed only in thermophiles/hyperthermophiles (HT-only group) and mesophiles (M-only group). A significant relationship between amino acid composition and optimal growth temperature (OGT) was observed. There were significantly higher proportions of charged, basic and acidic amino acids in hyperthermophilic and thermophilic genomes than in mesophilic and psychrophilic genomes. The orthologs distributed in all the four temperature ranges (Top-90 group) were also investigated, and a similar correlation between amino acid composition and OGT was found. The composition of the cluster of orthologous groups of proteins (COG) of the above three groups was analyzed; the composition of ‘information storage and processing’ in the HT-only group and Top-90 groups was much higher than that of M-only group.

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