PMID:27053110

Citation	'Kafle, P, Amoh, AN, Reaves, JM, Suneby, EG, Tutunjian, KA, Tyson, RL and Schneider, TL (2016) Molecular Insights into the Impact of Oxidative Stress on Quorum Sensing Regulator Protein LasR. J. Biol. Chem. '
Abstract	The LasR regulator protein functions at the top of thePseudomonas aeruginosaquorum sensing hierarchy and is implicated in promoting bacterial virulence. Of note is recent evidence that this transcription factor may also respond to oxidative stress. Here, all cysteines in LasR were inspected to deduce their redox sensitivity and to probe the connection between stress response and LasR activity using purified LasR and individual LasR domains. Cys79 in the ligand binding domain of LasR appears to be important for ligand recognition and folding of this domain in order to potentiate DNA binding but does not seem to be sensitive to oxidative stress when bound to its native ligand. Two cysteines in the DNA binding domain of LasR do form a disulfide bond when treated with hydrogen peroxide, and formation of this Cys201-Cys203 disulfide bond appears to disrupt the DNA binding activity of the transcription factor. Mutagenesis of either of these cysteines leads to expression of a protein that no longer binds DNA. A cell-based reporter assay linking LasR function with β-galactosidase activity gave results consistent with those obtained with purified LasR. This work provides a possible mechanism for oxidative stress response by LasR and indicates that multiple cysteines within the protein may prove useful targets for disabling its activity.
Links	PubMed Online version:10.1074/jbc.M116.719351
Keywords
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
PSEAE:LASR		GO:0006979: response to oxidative stress	ECO:0000315:		P		Figure 3.A. Proteins shifted DNA in the absence of oxidant.	complete CACAO 11702

References

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