Substrate recognition of pre-tRNA by ribonuclease P---subsite model of natural ribozyme originated from Escherichia coli.

Combination of cleavage site analysis and kinetic analysis of a series of shape variant of pre-tRNA substrate, we newly found two subsites which contribute to recognition of shape in substrate binding and catalysis by bacterial RNase P. Our data showed that the ribozyme traps the substrate by 5'- and 3'-end regions to form Michaelis complex, and after that the shape of the substrate is examined by other two subsites in the transition state. In the meeting, we will show the possibility that the S-domain can contribute to stabilize the transition state of the cleavage reaction of a pre-tRNA substrate.