Figure 3.
Binding of anticodon arm analogues to 30S ribosomal subunits or 70S ribosomes. The sequence and secondary structure of the anticodon stem-loop region of tRNAPhe (E. coli) is shown. RNA oligonucleotides (15-mers) containing a single phosphorothioate substitution at the indicated positions were synthesized and the Rp- and Sp-containing diastereoisomers separated by reverse phase HPLC. The relative binding efficiencies of the various oligonucleotides to 30S subunits in the presence of poly(U) determined by filter binding assay are indicated as fraction of bound anticodon arm analogue compared with the unsubstituted anticodon arm analogue (1.0, single point measurements). For binding to 70S ribosomes, identical values (within the variations indicated) were determined.