RESUMO
We evaluated the energetic stability of all possible 10-base fragments of the small subunit (SS) rRNA with a large ensemble of mRNAs. Results show that the 530 loop is the only conserved region that interacts favorably around the start codon as well as the elongation region of messengers. The interaction profile of the 530 loop around the stop codon showed that base pairing was energetically unfavorable in that region. With these results we constructed a simple scheme for the role of rRNA-mRNA interactions in the protein translation mechanism.
Assuntos
RNA Mensageiro/química , RNA Ribossômico/química , Sequência de Bases , Sítios de Ligação/genética , Códon de Terminação/química , Códon de Terminação/genética , Códon de Terminação/metabolismo , Humanos , Biossíntese de Proteínas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Ribossômico/genética , RNA Ribossômico/metabolismo , TermodinâmicaRESUMO
Linguistic similarities and dissimilarities between 5 S rRNA sequences allowed taxonomical separation of species and classes. Comparisons with the molecule from mammals distinguished fungi and plants from protists and animals. Similarities to mammalians progressively increased from protists to invertebrates and to somatic-type molecules of the vertebrates lineage. In this, deviations were detected in avian, oocyte type, and pseudogene sequences. Among bacteria, actinobacteria were most similar to the mammalians, which could be related to the high frequency of associations among members of these groups. Some archaebacterial species most similar to the mammalians belonged to the Thermoproteales and Halobacteria groups. Comparisons with the soybean mitochondrial molecule revealed high internal homogeneity among plant mitochondria. The eubacterial groups most similar to it were Thermus and Rhodobacteria gamma-1 and alpha-2. Other procedures have already indicated similarities of Rhodobacteria alpha to mitochondria but the linguistic similarities were on the average higher with the first two groups.