CAM dimer crosslinking at the entrance to the exit tunnel, upon UV-irradiation.

<p>Ribosomes from <i>E</i>. <i>coli</i> were irradiated with 365 nm light for 30 min (panels A-C), in the absence (lane 1) or the presence of compound 4 (lanes 2 and 3) or compound 5 (lanes 5 and 6). The irradiation products were analyzed by probing with DMS (panels A and B) or CMCT (panel C) and primer extension, before (lanes 3 and 6) or after discharging from excess CAM dimer (lanes 2 and 5). Probing and primer extension analysis were also applied to non-treated ribosomes (lane 4). Numbering of nucleosides for the sequencing lanes is indicated at the left. (A) Analysis of the A2600-U2615 region of 23S rRNA. (B) Analysis of the C2055-A2065 region (entrance to the exit tunnel) of 23S rRNA. (C) Analysis of the A2500-U2506 region (PTase catalytic center) of 23S rRNA.