Fig. 1.
Secondary structure of the Cac T-box (i.e., NT-box). Stem I contains the conserved GA motif and AG box, as well as the SL that displays the GAA and the AAC codons, encoding respectively for Glu and Asn. On the SL, the base pairing of the anticodon sequence of tRNAAsn and tRNAGlu is shown. The 3′ end conformations of the terminator and antiterminator structure are shown in comparison. Chemical probing was performed as described in Fig. S1 by using DMS, KE, and CMCT as chemical modification agents. The nucleotides that were accessible for chemical modification are marked using triangles. The protection (star) against modification of specific nucleotides in the SL and the T-box bulge occurs when the tRNA binds the T-box.