Download - QS Mechansim- Structural Analysis
Deciphering the QS Mechanism: Structural
AnalysisSahana.V
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Quorum Sensing: The basic mechanism
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Gram Negative
Passive Diffusion
Gram Positive
Two component regulated
LuxR ‘solo’ receptor
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Escherichia coli and its ‘solo’ receptor• SdiA – Role in E.coli is not completely understood.• Increases transcription of the cell division operon ftsQAZ• Increases resistance to certain antibiotics and quinolones, probably
through activation of efflux pumps• E. coli – activates Salmonella and E. coli gene promoters in an AHL
dependent manner • Monitor strains :• Pseudomonas fluorescens (produces N-octanoylL-homoserine lactone)• Pseudomonas syringae (produces N-hexanoyl-L-homoserine lactone)• Pseudomonas aeruginosa (produces N-butyryl-L-homoserine lactone)
Ahmer, 2004; Rahmati et al., 2002; Sitnikov et al., 1996 4/12
Interactions: Receptor and Signal Molecule
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Receptor: Its Role
Guozhou Chen et al., 2011
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Chromobacterium violecium
Guozhou Chen et al., 2011
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• PDB ID: 3QP2• Ligand: C8 HSL• Binding Site:
• Tyr-80, Trp-84, Asp-97, Ser-155 [Conserved]
• PDB ID: 3QP1• Ligand: C6 HSL• Binding Site:
• Tyr-80, Trp-84, Asp-97, Ser-155[Conserved]
Guozhou Chen et al., 2011
Wallace A C, et al., 1996
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Pseudomonas aeruginosa
Pseudomonas aeruginosa
• PDB ID: 2UV0• Ligand: 3-oxo-C12 HSL• Binding Site:
• Tyr-56, Trp-60, Asp-73, Ser-129 [Conserved]
Bottomleyet.al,2011
Wallace A C, et al., 1996
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Escherichia coli
Escherichia coli
• PDB ID: 4Y17• Ligand: C6- HSL• Binding Site:
• Trp-67, Asp-80, Ser-43 [Conserved]Y Nguyen et al.,2015Truc Kim et al., 2013
Wallace A C, et al., 1996
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Agrobacterium tumefaciens
Agrobacterium tumefaciens
• PDB ID: 1H0M• Ligand: 3-oxo-C8 AHL• Binding Site:
• Tyr-57, Asp-70 [Conserved]Vannini et al.,2002
Wallace A C, et al., 1996
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Common Points1. Ligand Binding Domain2. DNA Binding Domain
Domains
TyrosineTryptophanAspartic AcidSerine
Binding Site
Hydrophobic PocketHydrogen Bonds
Environment
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