TABLE 5.
Alanine substitutions in RhaS H-T-H 2 analyzed at wild-type rhaB-lacZ
| RhaS derivative | % of wild-type activitya (sp act [U]) |
|---|---|
| Cys246Ala | 66 (174) |
| Gly247Ala | 6.2 (33) |
| Phe248Ala | 0.9 (2.3) |
| Asp250Ala | 8.3 (44) |
| Asn252Ala | 31 (80) |
| His253Ala | 48 (153) |
| Phe254Ala | 1.2 (3.2) |
| Ser255Ala | 80 (210) |
| Thr256Ala | 61 (208) |
a
β-Galactosidase specific activity was measured from a single-copy rhaB-lacZ fusion in a rhaS deletion strain transformed with plasmids encoding either a wild-type or mutant form of RhaS. Cultures were grown in MOPS growth medium containing glycerol, l-rhamnose, and appropriate antibiotic. The activity of RhaS mutants is represented as the percentage of the activity of wild-type RhaS. Standard errors were less than 8% of the average units.