TABLE 2.
Effects of a glnK null allele on activity of the K. pneumoniae NifL protein
| Straina | Relevant genotype | Expression of nifH′-′lacZb (U/ml/OD600)
|
|
|---|---|---|---|
| With IPTGc | Without IPTG | ||
| NCM1528 | Wild type/Ptac-nifLA | 5,780 | 2,060 |
| NCM1974 | glnK/Ptac-nifLA | <10 | <10 |
| NCM1975 | glnK/Ptac-nifA | 6,310 | NDd |
| NCM1990 | glnK/Ptac-nifLA/pACYC184 | <10 | ND |
| NCM1982 | glnK/Ptac-nifLA Pcat-glnK+ | ND | 1,180 |
| NCM2069 | glnK/Ptac-nifLA PglnK-glnK+ | 5,160 | 1,950 |
a
All strains carry a single chromosomal copy of a nifH′-′lacZ fusion at the trp locus.
b
Specific activity is the slope of a plot of β-galactosidase activity versus the OD600 of the culture. Cultures were grown in K medium under anaerobic conditions with 2 mM glutamine as the sole nitrogen source.
c
10 μM.
d
ND, not determined.