title: Novel insights from molecular docking of SdiA from Salmonella Enteritidis and Escherichia coli with quorum sensing and quorum quenching molecules.
abstract: Quorum sensing is a cell-to-cell communication mechanism leading to differential gene expression in response to high population density. The autoinducer-1 (AI-1) type quorum sensing system is incomplete in Escherichia coli and Salmonella due to the lack of the AI-1 synthase (LuxI homolog) responsible for acyl homoserine lactone (AHL) synthesis. However, these bacteria encode the AHL receptor SdiA (a LuxR homolog) leading to gene regulation in response to AI-1 produced by other bacteria. This study aimed to model the SdiA protein of Salmonella enterica serovar Enteritidis PT4 578 based on three crystallized SdiA structures from Enterohemorrhagic E. coli (EHEC) with different ligands. Molecular docking of these predicted structures with AHLs, furanones and 1-octanoyl-rac-glycerol were also performed. The available EHEC SdiA structures provided good prototypes for modeling SdiA from Salmonella. The molecular docking of these proteins showed that residues Y63, W67, Y71, D80 and S134 are common binding sites for different quorum modulating signals, besides being conserved among other LuxR type proteins. We also show that AHLs with twelve carbons presented better binding affinity to SdiA than AHLs with smaller side chains in our docking analysis, regardless of the protein structures used. Interestingly, the conformational changes provided by AHL binding resulted in structural models with increased affinities to brominated furanones. These results suggest that the use of brominated furanones to inhibit phenotypes controlled by quorum sensing in Salmonella and EHEC may present a good strategy since these inhibitors seem to specifically compete with AHLs for binding to SdiA in both pathogens.
authors: Department of Microbiology, Laboratory of Food Microbiology, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil.
authors: Felipe Alves de
authors: FA
authors: Almeida
authors: Food Research Center, Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, Universidade de São Paulo, São Paulo, SP, Brazil.
authors: Uelinton Manoel
authors: UM
authors: Pinto
authors: Department of Microbiology, Laboratory of Food Microbiology, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil. Electronic address: mvanetti@ufv.br.
authors: Maria Cristina Dantas
authors: MC
authors: Vanetti
mesh_terms: D054742:Acyl-Butyrolactones / Q000737:chemistry / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D001665:Binding Sites; D004926:Escherichia coli / Q000201:enzymology*; D005663:Furans / Q000737:chemistry / Q000378:metabolism; D005989:Glycerides / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D062105:Molecular Docking Simulation; D000442:Octanols / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D012477:Salmonella enteritidis / Q000201:enzymology*; D015534:Trans-Activators / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D054742:Acyl-Butyrolactones; D001426:Bacterial Proteins; D005663:Furans; D005989:Glycerides; D000442:Octanols; C097686:SdiA protein, bacteria; D015534:Trans-Activators
keywords: 1-Octanoyl-rac-glycerol; Acyl homoserine lactone; Autoinducer; Furanone; LuxR family proteins; Molecular modeling