Table 1.
In vitro release activity of human Glu55 and Tyr125 eRF1 mutants
| Mutant eRF1 | Release activity (%) | ||
|---|---|---|---|
| UAAA | UAGA | UGAA | |
| E55A | 59 | 0 | 48 |
| E55D | 72 | 21 | 78 |
| E55Q | 75 | 35 | 80 |
| E55R | 98 | 97 | 104 |
| E55Y | 11 | 2 | 56 |
| E55S | 27 | 1 | 36 |
| Y125A | 5 | 6 | 8 |
| Y125E | 12 | 14 | 19 |
| Y125F | 100 | 34 | 100 |
| Y125S | 17 | 2 | 54 |
The release activity of mutant eRF1s was measured according to the in vitro Caskey's assay as described previously (20,28). Data are given in % versus the wt-eRF1. Average values from three independent experiments run in duplicates are presented. One-letter amino acid code is used. An error in RF activity measurements varied from 8.5 to 10% for different mutants. Background values (without any stop codon) were subtracted everywhere.