TABLE 3.
cosB mutations that enable packaging by 21-specific terminases reduce packaging by λ-specific terminase
| Line | Helpera | Initial cosb | Prophage yieldcd (SEM) | Helper | Prophage initial cos | Prophage yieldcd (SEM) | Discrimination indexe |
|---|---|---|---|---|---|---|---|
| 1 | λ-P1 Nu1hy1 (Hλ TλH21 wλ) | cosBλ | 0.20 (0.046) | λ-P1 Nu1hy1 (Hλ TλH21 wλ) | cosB21 | 2.87 (0.36) | 14.4 |
| 2 | λ-P1 Nu1+ | cos+Bλ | 0.84 (0.15) | λ-P1 Nu1hy51 (H21 T21H21 w21) | cosBλ | 4.55 (0.12) × 10−5 | 1.8 × 104 |
| 3 | λ-P1 Nu1+ | cosBλC59G | 0.13 (0.016) | λ-P1 Nu1hy51 (H21 T21H21 w21) | cosBλC59G | 2.05 (0.26) × 10−3 | 63 |
| 4 |
λ-P1 Nu1+ |
cosBλA117C |
0.09 (0.015) |
λ-P1 Nu1hy51 (H21 T21H21 w21) |
cosBλA117C |
4.1 (1.7) × 10−4 |
219 |
a
The genetic background for helper phages was λ-P1:5R cI857 nin5 Δbet-gam∷kan. Helper phage yields varied from 0.58 to 3.03.
b
The initial cos is the left cos at which DNA packaging initiates (Figure 2).
c
Plaque-forming units/induced lysogen.
d
Values in parentheses are the standard error of the mean (3 ≤ n ≤ 5).
e
Discrimination index is the yield of cognate prophage/yield of noncognate passive prophage.