MAINTAINING GENETIC-CODE THROUGH ADAPTATIONS OF TRANSFER-RNA SYNTHETASES TO TAXONOMIC DOMAINS

The universal genetic code is determined by the aminoacylation of tRNA s. In spite of the universality of the code, there are barriers to ami noacylation across taxonomic domains. These barriers are thought to co rrelate with the co-segregation of sequences of synthetases and tRNAs into distinct taxonomic domains. By contrast, we show here examples of eukaryote-like synthetases that are found in certain prokaryotes. The associated tRNAs have retained their prokaryote-like character in eac h instance, Thus, co-segregation of domain-specific synthetases and tR NAs does not always occur, Instead, synthetases make adaptations of tR NA-protein contacts to cross taxonomic domains.