title: Blocking of the initiation of protein biosynthesis by a pentanucleotide complementary to the 3' end of Escherichia coli 16 S rRNA.
abstract: Hydrogen bonding between the 3' terminus of 16 S rRNA (... C-A-C-C-U-C-C-U-U-A-OH3) and complementary sequences within the initiator region of mRNA may be a crucial event in the specific initiation of protein biosynthesis (Shine, J., and Dalgarno, L. (1974) Proc. Natl. Acad. Sci. U. S. A. 71, 1342-1346; Steitz, J. A., and Jakes, K. (1975) Proc. Natl. Acad. Sci. U. S. A. 72, 4734-4738). Using equilibrium dialysis, we have studied the binding of G-A-dG-dG-U (which is complementary to the 3' end of 16 S rRNA and which has been synthesized enzymatically) to initiation factor-free Escherichia coli ribosomes. We have also investigated the effects of the pentanucleotide on initiation reactions in E. coli ribosomes. G-A-dG-dG-U has a specific binding site on the 30 S ribosome with an association constant of 2 x 10(6) M-1 at 0 degrees C. G-A-dG-dG-U inhibits the R17 mRNA-dependent binding of fMet-tRNA by about 70%, both with 70 S ribosomes and 30 S subunits. In contrast, the A-U-G-dependent initiation reaction and the poly(U)-dependent Phe-tRNA binding was not affected by the pentanucleotide with both ribosomal species.
mesh_terms: D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D009693:Nucleic Acid Hybridization; D009841:Oligonucleotides / Q000494:pharmacology*; D009843:Oligoribonucleotides / Q000138:chemical synthesis / Q000494:pharmacology*; D010442:Peptide Chain Initiation, Translational / Q000187:drug effects*; D010448:Peptide Initiation Factors / Q000378:metabolism; D012335:RNA, Ribosomal / Q000378:metabolism*; D012270:Ribosomes / Q000187:drug effects / Q000378:metabolism
chemical_list: D009841:Oligonucleotides; D009843:Oligoribonucleotides; D010448:Peptide Initiation Factors; D012335:RNA, Ribosomal