Figure 4.

ENU modification–interference analyses. PhosphorImager printout of polyacrylamide gels showing separation of selected or nonselected bases of E. coli tRNA_f^Met (A) or tRNA^Phe (B) with ENU modification after cleavage (lanes: 1, total, unselected tRNA; 2, selection with 30S subunits; 3, selection with 70S ribosomes). Positions of interference are indicated. The ethylated phosphate at nucleotide U33 in tRNA_f^Met is lacking (shown in parentheses) as 2′-O-methylation of base C32 prevents hydrolysis between these bases. T₁, partial T₁-digest of [³²P]-end-labeled tRNAs. tRNA^Phe was 5′ and tRNA_f^Met was 3′ [³²P]-end-labeled, respectively.