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Chaperonin-dependent accelerated substitution rates in prokaryotes
1Institute of Botany III, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany.
Genome Biology and Evolution
|July 28, 2010
Summary
Molecular chaperones like GroEL/GroES assist protein folding. Studies show GroEL dependency accelerates evolutionary rates by buffering mutations, with obligatory chaperones evolving fastest.
Area of Science:
- Molecular biology
- Evolutionary biology
- Genomics
Background:
- Proteins require molecular chaperones for efficient folding.
- Chaperones, such as the GroEL/GroES system, can mask mutation effects by compensating for misfolding.
- Proteins are categorized by their dependency on GroEL for folding.
Purpose of the Study:
- To investigate the evolutionary impact of GroEL dependency on protein evolution.
- To determine if GroEL's buffering effects influence genome evolution rates.
Main Methods:
- Analyzed 446 proteobacterial genomes.
- Compared amino acid replacement frequencies in orthologs of 236 proteins across three GroEL dependency classes.
- Assessed correlations between GroEL dependency, evolutionary rates, and codon bias.
Main Results:
- Evolutionary rates significantly correlate with GroEL dependency, explaining up to 84% of variation.
- Obligatory GroEL-dependent proteins (Class III) evolve up to 35% faster than independent proteins (Class I).
- Correlations are conserved across proteobacteria and linked to codon bias.
Conclusions:
- GroEL-dependent folding accelerates evolutionary rates by buffering deleterious mutations.
- This buffering mechanism plays a significant role in shaping protein evolution across proteobacteria.
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