TABLE 4.
Effect on uhpT-lacZ expression of amino acid substitutions in conserved residues in GST-Bc with activating mutations
| Substitution in conserved residues | β-Galactosidase activity in uhpT-lacZ host straina
|
|||||
|---|---|---|---|---|---|---|
|
uhp+
|
ΔuhpBCb
|
|||||
| WT | E295G + E302K | R324C | WT | E295G + E302K | R324C | |
| Vector | 3/497 | 7/454 | 7/450 | 7/3 | 7/8 | 7/8 |
| WT GST-Bc | 1/2 | 490/482 | 285/281 | 1/2 | 481/457 | 381/343 |
| H313E | 3/2 | 3/2 | 2/22 | ND | 4/4 | 5/3 |
| H313Q | 4/2 | 3/4 | 2/3 | ND | 3/3 | 3/4 |
| N424D | 4/2 | 2/17 | 2/2 | ND | 3/3 | 2/3 |
| H428Q | 1/2 | 1/3 | 2/2 | ND | 3/2 | 3/3 |
| G boxc | 2/2 | 2/51 | 1/12 | ND | 3/3 | 3/2 |
a
β-Galactosidase units are presented for cells grown in the absence/presence of Glu6P in host strains with the indicated activating mutation or wild type (WT). ND, not determined.
b
Identical results were obtained with host strains carrying ΔuhpB or ΔuhpC alleles.
c
G box substitutions comprise the following four substitutions: D451A, D452A, G453A, and G455A.