Fidelity in archaeal information processing

Abstract

A key element during the flow of genetic information in living systems is fidelity. The accuracy of DNA replication influences the genome size as well as the rate of genome evolution. The large amount of energy invested in gene expression implies that fidelity plays a major role in fitness. On the other hand, an increase in fidelity generally coincides with a decrease in velocity. Hence, an important determinant of the evolution of life has been the establishment of a delicate balance between fidelity and variability. This paper reviews the current knowledge on quality control in archaeal information processing. While the majority of these processes are homologous in Archaea, Bacteria, and Eukaryotes, examples are provided of nonorthologous factors and processes operating in the archaeal domain. In some instances, evidence for the existence of certain fidelity mechanisms has been provided, but the factors involved still remain to be identified.

Figure 1

Overview of the processes involved in genetic Information Processing in Archaea (TFS: Transcription Factor S; TME: tRNA modifying enzymes; aa-RS: aminoacyl-tRNA synthetase; aIF2(γ): archaeal Initiation Factor 2(γ); aEF1α: archaeal Elongation Factor 1α).

Figure 2

tRNAs. (a) Schematic representation, showing the D-loop (green), anticodon loop (blue) that harbours the anticodon (grey), variable loop that is variable in length (light blue), the T-loop (yellow), the acceptor stem (red), and the CCA aminoacyl binding site (orange). The Levitt base pair is coloured purple. Nucleotides with thick boxes are often modified with variable modifications. (b) Tertiary structure of a yeast tRNA^Phe, coloured similar to (a). Figure is rendered with PyMOL from data deposited in the Protein Data Bank (1 ehz).