PEDS Advance Access originally published online on February 2, 2008
Protein Engineering Design and Selection 2008 21(4):275-278; doi:10.1093/protein/gzn001
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Short communications |
Revisiting the correlation between proteins' thermoresistance and organisms' thermophilicity
Unité de Bioinformatique génomique et structurale, Université Libre de Bruxelles, Av. F. Roosevelt 50, CP 165/61, 1050 Brussels, Belgium
1 To whom correspondence should be addressed. E-mail: ydehouck{at}ulb.ac.be
The possibility to rationally design protein mutants that remain structured and active at high temperatures strongly depends on a better understanding of the mechanisms of protein thermostability. Studies devoted to this issue often rely on the living temperature (Tenv) of the host organism rather than on the melting temperature (Tm) of the analyzed protein. To investigate the scale of this approximation, we probed the relationship between Tm and Tenv on a dataset of 127 proteins, and found a much weaker correlation than previously expected: the correlation coefficient is equal to 0.59 and the regression line is Tm
42.9°C + 0.62Tenv. To illustrate the effect of using Tenv rather than Tm to analyze protein thermoresistance, we derive statistical distance potentials, describing Glu–Arg and Asp–Arg salt bridges, from protein structure sets with high or low Tm or Tenv. The results show that the more favorable nature of salt bridges, relative to other interactions, at high temperatures is more clear-cut when defining thermoresistance in terms of Tm. The Tenv-based sets nevertheless remain informative.
Keywords: living temperature/melting temperature/salt bridges/statistical potentials/thermal stability
Received November 21, 2007; revised December 20, 2007; accepted December 31, 2007.