TABLE 1.
Plasmida | Protein | Succinate plate assay results | Capillary assay results | Response time (s)b
|
Ratio of FAD (induced/uninduced)c | Residue subtituted is Aer specificd | |
---|---|---|---|---|---|---|---|
O2 increase | O2 decrease | ||||||
pProEX HTa | Vector | − | − | 0 | 0 | 0.96 ± 0.18 | |
pAVR2 | His6-Aer2-506 | + | + | 173.8 ± 10.4 | 26.6 ± 3.0 | 4.98 ± 2.62 | |
pQH30 | His6-AerQ218C | + | + | >180e | 26.3 ± 10.2 | + | No |
pQH31 | His6-AerK221C | + | + | >180e | 33.0 ± 5.6 | + | No |
pQH32 | His6-AerV222C | + | + | 159.3 ± 24.9 | 31.8 ± 5.5 | + | No |
pQH33 | His6-AerE226C | + | + | 97.2 ± 13.8 | 23.3 ± 5.4 | + | No |
pQH34 | His6-AerR227C | + | + | >180e | 35.3 ± 7.3 | + | Yes |
pQH36 | His6-AerE231C | + | + | >180e | 27.8 ± 2.4 | + | Yes |
pQH38 | His6-AerR235C | − | − | 0 | 0 | 1.02 ± 0.01 | Yes |
pQH39 | His6-AerR235E | − | − | 0 | 0 | 0.69 ± 0.03 | Yes |
pQH40 | His6-AerR235K | + | + | 70.0 ± 7.9 | 12.2 ± 1.5 | + | Yes |
pQH43 | His6-AerD237C | + | + | 103.7 ± 41.0 | 14.5 ± 2.2 | + | No |
pQH44 | His6-AerL239C | + | + | 174.2 ± 9.2 | 25.3 ± 7.4 | + | No |
pQH46 | His6-AerT242C | + | + | >180e | 23.2 ± 1.5 | + | No |
pQH47 | His6-AerG250C | + | + | 46.9 ± 17.6 | 25.1 ± 5.7 | 2.94 ± 0.62 | Yes |
All plasmids were derived from the pProEX HTa expression vector.
The data represent means ± standard deviations of results for two independent experiments, each with three trials.
All Aer mutants were induced with IPTG to at least 2,500 copies per cell, which is eightfold higher than Aer expressed chromosomally (300 copies cell−1). Membranes from cells with the pProEx vector alone (aer) contained ≈500 copies of FAD cell−1. A 20% increase (ratio, 1.2) in total membrane FAD after IPTG induction was used to indicate FAD binding to Aer. +, aerotaxis activity was evidence that Aer was expressed and that it bound FAD in these strains.
Yes, the residue is not conserved in HAMP domains other than Aer.
Response times were variable within a range of 190 to ≈250 s.