Reduction in structural disorder and functional complexity in the thermal adaptation of prokaryotes.

TitleReduction in structural disorder and functional complexity in the thermal adaptation of prokaryotes.
Publication TypeJournal Article
Year of Publication2010
AuthorsBurra, P. V., L. Kalmar, and P. Tompa
JournalPLoS One
Date Published2010
Type of Articleidp
KeywordsAdaptation, Physiological, Bacteria, Bacterial Physiological Phenomena, Bacterial Proteins, Genome, Bacterial, Temperature, Transcription Factors

Genomic correlates of evolutionary adaptation to very low or very high optimal growth temperature (OGT) values have been the subject of many studies. Whereas these provided a protein-structural rationale of the activity and stability of globular proteins/enzymes, the point has been neglected that adaptation to extreme temperatures could also have resulted from an increased use of intrinsically disordered proteins (IDPs), which are resistant to these conditions in vitro. Contrary to these expectations, we found a conspicuously low level of structural disorder in bacteria of very high (and very low) OGT values. This paucity of disorder does not reflect phylogenetic relatedness, i.e. it is a result of genuine adaptation to extreme conditions. Because intrinsic disorder correlates with important regulatory functions, we asked how these bacteria could exist without IDPs by studying transcription factors, known to harbor a lot of function-related intrinsic disorder. Hyperthermophiles have much less transcription factors, which have reduced disorder compared to their mesophilic counterparts. On the other hand, we found by systematic categorization of proteins with long disordered regions that there are certain functions, such as translation and ribosome biogenesis that depend on structural disorder even in hyperthermophiles. In all, our observations suggest that adaptation to extreme conditions is achieved by a significant functional simplification, apparent at both the level of the genome and individual genes/proteins.

Alternate JournalPLoS ONE
PubMed ID20711457
PubMed Central IDPMC2920320