Table 2. Mutant ZFRs selected for recombination of Zcas6Z sites.
| Z Site | ||||||||
| 2nd Round Mutations | No. | Ztn3Z | Zcas1Z | Zcas2Z | Zcas3Z | Zcas4Z | Zcas5Z | Zcas6Z |
| ZFR310 | W | W | W | R | W | W | R | |
| N31D M53R N127K | 1 | W | W | W | W | W | W | W |
| I3P V108A | 1 | W | W | W | W | W | W | W |
| L135R | 2 | W | W | W | W | W | W | W |
| S12R D17E | 1 | W | W | W | W | W | W | W |
| S12R I103V | 1 | W | W | W | W | W | W | W |
| E132A (ZFR320) | 5 | W | W | W | W | W | W | W |
| I3L L135R | 1 | W | W | W | W | W | W | W |
| I3S E132A | 1 | W | W | W | W | W | W | W |
| N127H E132A | 1 | W | W | W | W | W | W | W |
| I3S D25A F83L | 1 | W | W | W | W | W | W | W |
The Table shows the ‘second round’ mutants isolated from screens of ZFR310 mutant libraries (ZFR310 is ZFR300 with the mutation I77L), using a test substrate containing two Zcas6Z sites. The left-hand column gives the mutations, and the next column indicates the number of independent isolates. The other columns show the phenotype of each mutant in the MacConkey agar colony colour assay, using substrates with two identical ZcasZ sites as indicated. W, ‘white’ (pale-coloured) colonies; R, red colonies; M, mixtures of pale and red colonies.