Table 2. Mating experiments to check for protein transfer into recipient cells.
Transfer elements in strain 1
|
R388 mutation in strain 2
|
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Experiment | Plasmids | oriT | trwA | trwB | trwC | T4SS R388 | T4SS pKM101 | oriT-mob CloDF13 | Transfer frequency | |
1. trwC control | pKM101Δmob + pET29c | + | trwC (pSU1445) | <10–7 | ||||||
2. trwB control | pKM101Δmob + pET29c | + | trwB (pSU1443) | <10–7 | ||||||
3. trwA control | pKM101Δmob + pET29c | + | trwA (pSU4028) | 8 × 10—6 | ||||||
4. TrwC transfer with DNA transfer | pKM101Δmob + pET29:trwABC + pSU1371 | + | + | + | + | + | trwC (pSU1445) | 8 × 10—3 | ||
5. TrwB transfer with DNA transfer | pKM101Δmob + pET29:trwABC + pSU1371 | + | + | + | + | + | trwB (pSU1443) | 8 × 10—7 | ||
6. TrwA transfer with DNA transfer | pKM101Δmob + pET29:trwABC + pBBR::oriT | + | + | + | + | + | trwA (pSU4028) | 2 × 10—6 | ||
7. TrwC transfer w/o DNA transfer | pKM101Δmob + pET29:trwABC | + | + | + | + | trwC (pSU1445) | 5 × 10—5 | |||
8. TrwB transfer w/o DNA transfer | pKM101Δmob + pET29:trwABC | + | + | + | + | trwB (pSU1443) | 2 × 10—7 | |||
9. TrwA transfer w/o DNA transfer | pKM101Δmob + pET29:trwABC | + | + | + | + | trwA (pSU4028) | 5 × 10—6 | |||
10. TrwC transfer w/CloDF DNA transfer | pKM101Δmob + pET29:trwABC + pSU4814 | + | + | + | + | + | trwC (pSU1445) | 5 × 10—5 | ||
11. Negative control for CloDF13 | pKM101Δmob + pET29c + pSU4814 | + | + | trwC (pSU1445) | <10—7 | |||||
12. TrwC transfer w/o coupling protein | pKM101Δmob + pET29:trwAC | + | + | + | trwC (pSU1445) | 2 × 10—7 | ||||
13. TrwC transfer with entry exclusion | pSU711ΔoriT::aac3 | + | + | + | + | trwC (pSU1445) | <10—7 | |||
14. TrwB transfer with entry exclusion | pSU711ΔoriT::aac3 | + | + | + | + | trwB (pSU1443) | <10—7 |
Triparental matings were performed as explained in Methods. The first column describes the aim of each experiment. To facilitate interpretation, the elements of the conjugative machinery present in strain 1 are indicated. Frequencies represent number of transconjugants per strain 2. Figures are the mean of two to six experiments.