Institute of Crystallography - CNR

Structural studies on the main mediators of quorum sensing and their regulation

Structural and functional characterization of the main mediators of quorum sensing (LuxRs) and of the structural basis of their specificity vs promiscuity towards different autoinducers. Structural studies on the role of ligands of physiological relevance, as modulators of their activity.

Homology modeling and structural analysis on proteins belonging to the LuxRs family, transcription factors among the main mediators of quorum sensing.
Cloning and mutagenesis of different LuxRs (LasR, CviR, RhlR, LoxR and SdiA), both specific and promiscuous towards the autoinducers, in both full length and Ligand Binding Domain format. Recombinant expression in soluble form in fusion with his-tag, purification by chromatographic systems, proteolytic removal of the tag and purification. Structural characterization of the binding modes of self-inductors in specific and promiscuous LuxRs by X-ray crystallography and of the effect of different self-inductors on the conformation of full-length proteins in solution, by molecular dynamics, limited proteolysis, DSF, Fluorescence and SAXS.
Analysis of the interaction of LuxRs with ligands of physiological relevance (i.e., flavonoids), using X-ray crystallography, SAXS, DSF, fluorescence, GCI and ITC.

Reference works

– Bez C., Covaceuzach S., Bertani I., Choudhary K.S., Venturi V. LuxR solos from environmental fluorescent pseudomonads. mSphere (2021) Mar 31;6(2):e01322-20.
– Mosquito S., Meng X., Devescovi G., Bertani I., Geller A.M., Levy A., Myers M.P., Bez C., Covaceuszach S., Venturi V. LuxR Solos in the Plant Endophyte Kosakonia sp. Strain KO348. Appl Environ Microbiol. 2020 Jun 17;86(13):e00622-20.
– Kumar Patel H., Ferrante P., Covaceuszach S., Lamba D., Scortichini M., Venturi V. The kiwifruit emerging pathogen Pseudomonas syringae pv. actinidiae does not produce AHLs but possesses three LuxR solos. PLoS One (2014) 9(1):e87862
– Covaceuszach S., Degrassi G., Venturi V., Lamba D. “Structural insights on a novel interkingdom signaling circuit by cartography of the ligand-binding sites of the homologous LuxR-family.” International Journal of Molecular Science (2013) 14(10):20578

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