Figure 1: Schematic representation of substrates for RNase P. (a) A natural substrate (ptRNA). (b) A hybridized complex of a target RNA (e.g., mRNA) and a EGS that resembles the structure of a tRNA. (c) and (d) Complexes between CCR5 mRNA sequence and EGS C1 and C2, respectively. The sequences of C1 and C2 that were equivalent to the T-stem and loop and variable region of a tRNA molecule were derived from . Only the exact sequence of the CCR5 mRNA around the targeting site was shown. The EGS sequence is shown in bold. The site of cleavage by RNase P is marked with an arrowhead. The three nucleotides that are mutated in C2 are in circles.