The Archaea Ribonuclease P: Molecular Mechanisms of Thermal Adaptation pp. 121-141
Authors: (Francisco Miralles, Département de Génétique et Développement, INSERM U567-CNRS UMR8104, Institut Cochin, Paris, France)
Abstract: Temperature is an essential and variable environmental factor, which impacts the phenotype, habitat distribution and evolution of organisms. The pervasive influence of temperature on organisms requieres an ensemble of compensatory adaptations that span all levels of biological organization, from behaviour to fine-scale molecular structure. The Archaea stand out as the only group of organisms that have species capable of growing at temperatures ranging from 0°C to 110°C. Thus, the recent availability of complete genome sequences for a large number of archaea species provides a powerful tool to analyze the mechanisms of thermal adaptation at the molecular level. In this study we have used comparative genomics to analyze thermal adaptation in the universally conserved ribonucleoprotein: Ribonuclease P (RNase P). We have analyzed compositional and structural features of both, the RNA and protein components of the archaeal RNase P, to identify molecular trends related to thermal adaptation. Our results show a robust correlation between the stems GC content of the RNase P RNA and the optimal growth temperature (OGT) of the archaea species. Moreover, we have detected significant differencesin the composition and distribution of several amino acids in the RNase P protein components of hyperthermophilic and mesophilic archaea. Thus, this study reveals that natural selection has adapted the RNase P holoenzyme to the OGT of the archaea species by modifying both, its RNA and proteins subunits.