Figure 4.

6sdG36 crosslink. A) Mapping of 6sdG36 crosslinked sites. The crosslinked sites were mapped by limited alkaline hydrolysis (Alk) and partial digestion with RNAse T1 (T1). The species consisting of 5′-³²P end-labeled substrate crosslinked to 6sdG36 ribozyme 3′ strand, (*S to 6dG36Rz3′ XL), and the end-labeled substrate control (*S) are paired on the left. The species consisting of 5′-³²P end-labeled 6sdG36 ribozyme 3′ strand crosslinked to substrate (S to 6sdG36*Rz3′ XL), and end-labeled 6sdG36 ribozyme 3′ strand control (6sdG36*Rz3′) are paired on the right. Sites of ribonuclease T1-induced cleavages are indicated by the numbered guanosine. B) Activity assay for isolated crosslinked species. Ribozyme 5′ strand (Rz5′) was added to crosslinked products labeled on ribozyme 3′ strand (*Rz3′), in the presence of 1 mM cobalt hexaammine for 2 hours. The crosslink cleavage product and the reversal to ribozyme 5′ strand are shown by arrows.