Int. J. Mol. Sci. 2013, 14(7), 13360-13376; doi:10.3390/ijms140713360
Article

Kinetic Model for Signal Binding to the Quorum Sensing Regulator LasR

1,2email, 2email, 2email, 2,3email, 4email, 5email and 1,* email
Received: 3 June 2013; in revised form: 19 June 2013 / Accepted: 20 June 2013 / Published: 27 June 2013
(This article belongs to the Special Issue Quorum Sensing Research in Microbial Systems)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: We propose a kinetic model for the activation of the las regulon in the opportunistic pathogen Pseudomonas aeruginosa. The model is based on in vitro data and accounts for the LasR dimerization and consecutive activation by binding of two OdDHL signal molecules. Experimentally, the production of the active LasR quorum-sensing regulator was studied in an Escherichia coli background as a function of signal molecule concentration. The functional activity of the regulator was monitored via a GFP reporter fusion to lasB expressed from the native lasB promoter. The new data shows that the active form of the LasR dimer binds two signal molecules cooperatively and that the timescale for reaching saturation is independent of the signal molecule concentration. This favors a picture where the dimerized regulator is protected against proteases and remains protected as it is activated through binding of two successive signal molecules. In absence of signal molecules, the dimerized regulator can dissociate and degrade through proteolytic turnover of the monomer. This resolves the apparent contradiction between our data and recent reports that the fully protected dimer is able to “degrade” when the induction of LasR ceases.
Keywords: quorum sensing; LasR; Pseudomonas aeruginosa; OdDHL; C12-HSL; signal molecule; ligand
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MDPI and ACS Style

Claussen, A.; Jakobsen, T.H.; Bjarnsholt, T.; Givskov, M.; Welch, M.; Ferkinghoff-Borg, J.; Sams, T. Kinetic Model for Signal Binding to the Quorum Sensing Regulator LasR. Int. J. Mol. Sci. 2013, 14, 13360-13376.

AMA Style

Claussen A, Jakobsen TH, Bjarnsholt T, Givskov M, Welch M, Ferkinghoff-Borg J, Sams T. Kinetic Model for Signal Binding to the Quorum Sensing Regulator LasR. International Journal of Molecular Sciences. 2013; 14(7):13360-13376.

Chicago/Turabian Style

Claussen, Anetta; Jakobsen, Tim H.; Bjarnsholt, Thomas; Givskov, Michael; Welch, Martin; Ferkinghoff-Borg, Jesper; Sams, Thomas. 2013. "Kinetic Model for Signal Binding to the Quorum Sensing Regulator LasR." Int. J. Mol. Sci. 14, no. 7: 13360-13376.

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