The 3' terminus of 16S rRNA: secondary structure and interaction with ribosomal protein S1.
AUTOR(ES)
Yuan, R C
RESUMO
We report studies of the secondary structure and S1 ribosomal protein binding properties of the colicin fragment, containing 49 residues from the 3' terminus of E. coli 16S rRNA. Temperature jump relaxation kinetic measurements reveal two helices in the structure. One of these, melting at 81 degrees C in 5 mM Mg2+, is associated with the 9-base pair hairpin helix predicted by the nucleotide sequence. The other melting transition, at 21 degrees C in 5 mM Mg2+, is assigned to a 4-base pair helix which constrains the pyrimidine tract of the colicin fragment into a bulge loop. S1 protein forms a strong 1:1 complex with the colicin fragment, with an association constant of 5 x 10(6) M-1 in 5 mM Mg2+. More protein molecules are bound, but with weaker affinity, when the S1 concentration is increased. S1 binding causes melting of the colicin fragment secondary structure, as inferred from the observed absorbance increase. The S1 binding site on the colicin fragment has been localized in the region of the bulge loop, since the melting transition corresponding to the 4-base pair helix is lost in the complex. We discuss current models for the role of S1 protein in polypeptide chain initiation in light of these and previous results.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=342392Documentos Relacionados
- Binding of ribosomal protein S1 of Escherichia coli to the 3' end of 16S rRNA.
- Interaction of Escherichia coli ribosomal protein S7 with 16S rRNA.
- Lessons from an evolving rRNA: 16S and 23S rRNA structures from a comparative perspective.
- The secondary structure of the protein L1 binding region of ribosomal 23S RNA. Homologies with putative secondary structures of the L11 mRNA and of a region of mitochondrial 16S rRNA
- Homology of the 3' terminal sequences of the 18S rRNA of Bombyx mori and the 16S rRNA of Escherchia coli.