Figure 4.
Effect of ABA-spermine cross-linking to 5S rRNA on translocation. (A) Time course of spontaneous translocation. Aliquots of PRE-complex, i.e. poly(U)-programmed 70S ribosomes occupied at their P- and A-sites with tRNAPhe and Ac[3H]Phe-tRNA, respectively, possessing (squares) wild-type or (circles) photolabeled 5S rRNA by 50 μM ABA-spermine, were incubated at 25°C for the indicated time intervals, in buffer B containing 0.12 mM GTP, (filled symbols) in the presence or (open symbols) in the absence of 50 μM free spermine. (B) Dependence of translocation on EF-G concentration. PRE-complex was incubated with different amounts of EF-G for 5 min at 25°C. The symbols are the same as those used in (A). In each plot, translocation of 100% represents conversion of all PRE-complex into POST-complex.