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Optimum growth temperature and the base composition of open reading frames in prokaryotes
R J Lambros1, J R Mortimer, D R Forsdyke
1Department of Biochemistry, Queen's University, Kingston, Ontario K7L3N6, Canada.
Extremophiles : Life Under Extreme Conditions
|December 11, 2003
Summary
Organisms use a purine-loading index (PLI) to reduce RNA-RNA interactions at higher temperatures. As temperature rises, prokaryotes increase adenine and decrease cytosine, raising PLI and lowering GC content in messenger RNAs.
Area of Science:
- Molecular Biology
- Genomics
- Biophysics
Background:
- RNA-RNA interactions are crucial in biological systems.
- These interactions are influenced by temperature and base composition.
- Minimizing self-complementarity in RNA is essential for function.
Purpose of the Study:
- To investigate the relationship between optimal growth temperature and RNA base composition in prokaryotes.
- To determine if the purine-loading index (PLI) correlates with temperature.
- To understand the implications for messenger RNA (mRNA) structure and function.
Main Methods:
- Calculated the purine-loading index (PLI) for mRNAs across 550 prokaryotic species.
- Analyzed the correlation between PLI and optimal growth temperature.
- Examined base composition changes (A, G, T, C) in relation to temperature.
Main Results:
- A positive correlation was found between optimal growth temperature and average PLI in prokaryotic mRNAs.
- Increasing temperatures were associated with increased adenine (A) and decreased cytosine (C) content.
- The (G+C)% content showed a negative correlation with optimal growth temperature for mRNAs.
Conclusions:
- Prokaryotes adapt their mRNA composition to minimize RNA-RNA interactions at higher temperatures.
- The purine-loading index is a key factor in this adaptation.
- This temperature-dependent base composition strategy differs from that observed in ribosomal and transfer RNAs.
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