Probing the architecture of the B. subtilis RNase P holoenzyme active site by cross-linking and affinity cleavage

Affinity cleavage of pre-tRNA^Asp by AOP-modified P protein. (A) Cleavage of radiolabeled pre-tRNA by RNase P formed with P protein modified with AOP in the central cleft. Control lanes show base hydrolysis (OH), RNase T1, and RNase U2 ladders. The RNase P cleavage site (CS) in pre-tRNA, 5′ leader nucleotides –3 and –7, and nucleotides 37 and 67 are labeled. (B) Cleavage of pre-tRNA by RNase P formed with P protein modified with AOP in the RNR motif. Control lanes are as in A. The RNase P cleavage site (CS) and 5′ leader positions–2 and –4 are shown.