TABLE 1.
Peptidyl transfer rates of rRNA mutants
S.E. are calculated from at least three independent determinations.
| Codon (tRNA) | WT (kPEP) | A1913U (kPEP) | G1922A (kPEP) | % Codona |
|---|---|---|---|---|
| s−1b | s−1b | s−1b | ||
| UUU (Phe) | 4.7 (0.86) | 4.6 (0.71) | 4.6 (1.0) | 2.2 |
| UUC (Phe) | 2.5 (0.53) | 2.3 (0.36) | 2.1 (0.14) | 1.7 |
| UGG (WT-Trp) | 2.5 (0.37) | 2.2 (0.27) | 2.4 (0.47) | 1.5 |
| UGG (Mut-Trp) | 1.6 (0.19) | 1.5 (0.29) | 1.3 (0.13) | 1.5 |
| UGA (WT-Trp) | .04 (0.01) | 0.02 (0.01) | 0.04 (0.02) | 0.09 |
| UGA (Mut-Trp) | .77 (0.11) | 0.03 (0.02) | 0.45 (0.11) | 0.09 |
| CGU (Arg-ICG) | 3.0 (0.50) | 2.9 (0.35) | 3.2 (0.48) | 2.1 |
| CGA (Arg-ICG) | 2.4 (0.23) | 0.37 (0.04) | 1.9 (0.16) | 0.40 |
| CGC (Arg-ICG) | 2.2 (0.31) | 2.1 (0.31) | 1.9 (0.38) | 2.2 |
| AUU (Ile-GAU) | 2.1 (0.47) | 2.1 (0.42) | 1.9 (0.41) | 3.0 |
| AUA (Ile-k2CAU) | 1.3 (0.28) | 0.20 (0.04) | 0.79 (0.23) | 0.43 |
a % Codon values calculated for E. coli K12 from the Genomic tRNA Database.
b kPEP is calculated at 1 μm ribosomes and 0.15 μm ternary complex. Values presented do not include a calculation for the rate of rejection (k7) seen in the CGA measurements.