Label-free measurement of antimicrobial peptide interactions with lipid vesicles and nanodiscs using microscale thermophoresis.

One strategy to combat antimicrobial resistance is the discovery of new classes of antibiotics. Most antibiotics will at some point interact with the bacterial membrane to either interfere with its integrity or to cross it. Reliable and efficient tools for determining the dissociation constant for membrane binding (K) and the partitioning coefficient between the aqueous- and membrane phases (K) are therefore important tools for discovering and optimizing antimicrobial hits.

Goldilocks Dilemma: LPS Works Both as the Initial Target and a Barrier for the Antimicrobial Action of Cationic AMPs on .

Antimicrobial peptides (AMPs) are generally membrane-active compounds that physically disrupt bacterial membranes. Despite extensive research, the precise mode of action of AMPs is still a topic of great debate. This work demonstrates that the initial interaction between the Gram-negative and AMPs is driven by lipopolysaccharides (LPS) that act as kinetic barriers for the binding of AMPs to the bacterial membrane.

WIND-PVPA: Water/Ion NMR Detected PVPA to assess lipid barrier integrity in vitro through quantification of passive water- and ion transport.

Water/Ion NMR Detected - Phospholipid Vesicle Permeability Assay (WIND-PVPA), is presented as a novel, straightforward and automatable method to assess lipid barrier integrity in vitro. The apparent permeability constants of water- and ions across the PVPA barriers are determined in a one-pot experiment under the influence of membrane-active guest molecules. NMR spectroscopy is used to quantify the water directly (DO) and the ions indirectly (complexed with EDTA) as a function of time.