Berlin 2008 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 7: Posters I

BP 7.4: Poster

Montag, 25. Februar 2008, 17:00–19:30, Poster A

Impact of alternative genetic codes on the stability of proteins — •Stefanie Sammet¹, Andreas Buhr¹, Ugo Bastolla², and Markus Porto¹ — ¹Institut für Festkörperphysik, Technische Universität Darmstadt, Germany — ²Centro de Biologia Molecular, "Severo Ochoa", Campus UAM, Cantoblanco, 28049 Madrid, Spain

While nearly all free-living species use the same genetic code for the translation of genes into amino acid sequences, slightly different genetic codes are used in mitochondria and in some intracellular bacteria. In addition, the mitochondria genome mainly codes for membrane proteins, which have peculiar thermodynamic properties since they have to deal with a lipidic environment. While there has been a lot of work concerned with the optimality of the standard genetic code, it remains unclear whether alternative codes provide any advantage to the proteins they code for. We present a model based on mutations and purifying selection on thermodynamic properties, which takes into account that mitochodrial genome present a distinctive mutation bias. On the basis of point mutations in the DNA, the effects of different genetic codes on stability against unfolding and misfolding are examined. Furthermore, the robustness of proteins against mistranslations is considered.