Summary of the outcomes of the PCR amplification and of the native purification for each RNA.

1tRNA (anticodon); SSU: small ribosomal subunit; td: thymidylate synthase; tmRNA: transfer-messenger RNA. 2P: precursor; Pm1: precursor containing mutations in the tRNA acceptor stem (A.s.) or in P6a (td); I: intron; Im1: intron containing mutations in P6a; Im1–12: variants #1 to #12 containing mutations in P6a. 3Comprises 35 additional base pairs to the variant sequence, corresponding to restriction sites and a T7 polymerase promoter. 4When two or more polymerases were tested, a star indicates which one was successful. 5See Materials and Methods for calculation details; n.d.: not determined; n.a.: not applicable. *Estimation based on the amount of cleaved off and uncleaved RNAs present in lanes e1 and r1 only (Fig. 3A; see Materials and Methods).