TABLE 2.
Relative activities of Cps2B mutant enzymesa
| Mutationb | Mutation located ind: |
Mean activity (%) (SEM)c | |
|---|---|---|---|
| PHP motif | Catalytic residue | ||
| Hydroxylamine-generated mutations | |||
| S6L | * | 0.23 (0.2) | |
| D14N | * | * | None detected |
| R19K | 32 (0.4) | ||
| S22N | 5.2 (0.3) | ||
| D72N | 6.2 (0.7) | ||
| A79V | 1.8 (0.1) | ||
| D86N | None detected | ||
| S102N | 3.2 (0.2) | ||
| E108K | * | None detected | |
| G129E | * | 20 (0.7) | |
| P132S | * | 0.01 (0.2) | |
| H136Y | * | * | None detected |
| C158Y | None detected | ||
| G205D | * | 59 (4.0) | |
| Site-specific mutations | |||
| H136A | * | * | None detected |
| C158A | 46 (0.9) | ||
| H201A | * | * | None detected |
a
Purified recombinant polyhistidine-tagged enzymes.
b
Underlined residues indicate mutations introduced into S. pneumoniae.
c
Percentage of D39 Cps2B activity, which exhibited a standard error of the mean of 3.3%. All mutants were significantly decreased in activity at a P value of <0.01 by one-way analysis of variance (ANOVA) with Dunnett's multiple-comparison posttest against the parent.
d
*, mutation is located in a PHP motif or catalytic residue.