TABLE 4.
Random mutations in RhaS H-T-H 2 analyzed at wild-type rhaB-lacZ
| RhaS derivative | % of wild-type activitya (sp act [U]) |
|---|---|
| Gly247Arg | 0.9 (3.8) |
| Phe248Val | 3.3 (17) |
| Ser249Gly | 93 (536) |
| Ser251Gly | 87 (505) |
| Asn252His | 0.4 (2.0) |
| Asn252Ser | 37 (184) |
| Asn252Ile | 0.3 (2.0) |
| His253Gln | 32 (185) |
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 21% of the average units.