A Method for Characterizing the Thermal Stability and Antimicrobial Binding to Lipopolysaccharides of Gram-negative Isogenic Mutant Strains.

Isothermal Titration Calorimetry (ITC) is widely employed to assess antimicrobial affinity for lipopolysaccharide (LPS); nevertheless, experiments are usually limited to commercially available-LPS chemotypes. Herein we show a method that uses Differential Scanning Calorimetry (DSC) to characterize homogeneity artificial vesicles of LPS (LPS-V) extracted from isogenic mutant bacterial strains before analyzing the antimicrobial binding by ITC. This method allows us to characterize the differences in the Polymyxin-B binding and gel to crystalline liquid (β↔α) phase profiles of LPS-V made of LPS extracted from Escherichia coli isogenic mutant strains for the LPS biosynthesis pathway, allowing us to obtain the comparable data required for new antimicrobial discovery. A method for:•Obtaining LPS vesicles from isogenic mutant bacterial strains.•Characterize artificial LPS vesicles homogeneity.•Characterize antimicrobial binding to LPS.