Category:Team Denitrifiers

Figure 4: NTRC often prohibits transcriptional activation at promoters that need o54. Both the wild-type NTRC-phosphate and the mutant phenotype yielded the protection of -25, -24, and -13 guanine residues; these resides may be necessary for Eo54 recognition. However, -8 and -9 may be responsible for open promoter complexes, and the mutant phenotype is unable to express high levels of -8 and -9, causing the promoter to remain in closed form.

Figure 2:NIFL is a regulatory protein that directs the transcriptional activities of nitrogen fixation genes. It does this by interacting with NIFA, which is an enhancer binding protein. Since previous research has shown that NIFL is a flavoprotein, this gene gets reduced in the presence of sodium dithionite. Transcription in inhibited when NIFL is oxidized. Transcriptional activiation can be measured by looking at the formation of open promoter complexes. This figure shows that sodium dithionite did not affect NIFA since the open promoter complexes were formed with or without the addition of sodium dithionite. This figure also shows that with the addition of sodium dithionite to NIFL and NIFA together, which would mean that NIFL is reduced, open promoter complexes were able to be formed. On the other hand, without sodium dithionite, NIFL is oxidized, and no open promoter complexes could be formed.

Table 3. Genes napKEFDABC were determined to be involved in denitrification in an experiment that measured gases released by four strains: wild-type, nap-bearing, napD-deficient mutant and non-nap bearing mutant that conjugated with another bacterium containing napKEFDABC. Wild-type strain produced gases which showed denitrification activity. napD deficient strain as well as non-nap bearing strain produced no gases and therefore no denitrification activity. Nap-deficient mutant that conjugated with nap-bearing bacterium regained denitrification activities.

Figure 8. Deletion-replacement mutagenesis of the gene norB resulted in the loss of NO reduction of P stutzeri strain MK321.

Figure 3. Columns 2 and 3 - Column 2 tracks seen (periplasmic) but not in column 3 (cytoplasmic).

Nap activity was detected, but associated with a band of decreased electrophoretic mobility which lacks c-type cytochrome, implying that NapA is active with the artificial electron donor, methyl viologen, in the absence of NapB (Fig. 1, track 2).

Figure 1. Periplasmic proteins separated and stained for nitrate reductase activity. Banding seen is due to the reduction of nitrite formed as the product of NapA activity by periplasmic nitrite reductase [20].

Figure 6,7. These figures show that the NIRA protein binds to the cis-acting sites of niaD and niiA.

Figure 4. Column 2 (0 min); Column 3 (2min) Column 4 (10min). As length of purification process increases, expression decreases - less expression in each consecutive column after column 2. Evidence that narJ is lost during lengthy purification process.

Figure 3: The wild type and mutants were able to convert nitrate to nitrite. Nitrite added up in the medium and was not able to be reduced to nitrogen oxide. But, with the nirS it was able to.

Figure 5: shows the hydrophobicity of a few nitrate reductase proteins. NirB, NirD, and CysG had relatively equal values of hydrophobic and hydrophilic residues, which indicated that it more closely resembled a protein found inside the cell such as a cytoplasmic protein. On the other hand, NirC had an abundance of hydrophobic residues, which indicates it may be part of the membrane. NirC has also been found to be comparable to a subunit that is part of the cytochrome oxidase polypeptide 1, which is a membrane bound chain of amino acids. Eisenberg and McLachlan created a model to calculate hydrophobicity and amphiphilcity that was used to determine the hydrophobicity of all of these proteins.

Figure 5.Figure shows that NosF protein is hydrophilic component w/o transmembrane helices. It doesn't carry an export signal therefore it is assumed to be located within the cytoplasm or at the inner face of the cytoplasmic membrane.

Table 2: Copper content in cells of mutant phenotypes drops dramatically indicating cells cannot import copper.