Structural Insights into the Ligand–LsrK Kinase Binding Mode: A Step Forward in the Discovery of Novel Antimicrobial Agents
Roberta Listro,
Giorgio Milli,
Angelica Pellegrini,
Chiara Motta,
Valeria Cavalloro,
Emanuela Martino,
Johannes Kirchmair,
Giampiero Pietrocola,
Daniela Rossi,
Pasquale Linciano,
Simona Collina
Affiliations
Roberta Listro
Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
Giorgio Milli
Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
Angelica Pellegrini
Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Viale Taramelli 3/b, 27100 Pavia, Italy
Chiara Motta
Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Viale Taramelli 3/b, 27100 Pavia, Italy
Valeria Cavalloro
Department of Earth and Environmental Sciences, University of Pavia, Via Sant ’Epifanio 14, 27100 Pavia, Italy
Emanuela Martino
Department of Earth and Environmental Sciences, University of Pavia, Via Sant ’Epifanio 14, 27100 Pavia, Italy
Johannes Kirchmair
Division of Pharmaceutical Chemistry, Department of Pharmaceutical Sciences, University of Vienna, Josef-Holaubek-Platz 2, 2D 303, 1090 Vienna, Austria
Giampiero Pietrocola
Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Viale Taramelli 3/b, 27100 Pavia, Italy
Daniela Rossi
Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
Pasquale Linciano
Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
Simona Collina
Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
LsrK is a bacterial kinase that triggers the quorum sensing, and it represents a druggable target for the identification of new agents for fighting antimicrobial resistance. Herein, we exploited tryptophan fluorescence spectroscopy (TFS) as a suitable technique for the identification of potential LsrK ligands from an in-house library of chemicals comprising synthetic compounds as well as secondary metabolites. Three secondary metabolites (Hib-ester, Hib-carbaldehyde and (R)-ASME) showed effective binding to LsrK, with KD values in the sub-micromolar range. The conformational changes were confirmed via circular dichroism and molecular docking results further validated the findings and displayed the specific mode of interaction. The activity of the identified compounds on the biofilm formation by some Staphylococcus spp. was investigated. Hib-carbaldehyde and (R)-ASME were able to reduce the production of biofilm, with (R)-ASME resulting in the most effective compound with an EC50 of 14 mg/well. The successful application of TFS highlights its usefulness in searching for promising LsrK inhibitor candidates with inhibitor efficacy against biofilm formation.
