Abstract:
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Membrane-active antimicrobial peptides, such as polymyxin B (PxB), are currently in the spotlight as potential candidates to
overcome bacterial resistance. We have designed synthetic analogs of
PxB in order to determine the structural requirements for membrane
action. Since the mechanism of action of PxB involves interaction with
both the outer membrane and the cytoplasmic membrane of Gram
negative bacteria, we have used an approach based on mimicking the
outer layers of these membranes using monolayers, Langmuir-Blodgett
films and unilamelar vesicles, and applying a battery of biophysical
methods in order to dissect the different events of membrane
interaction. Collectively, results indicate that the PxB analogues act in
the bacterial membrane by the same mechanism than PxB, and that cationic amphipathicity determines peptide activity. |