Journal article

Atomic force microscopy of bacteria reveals the mechanobiology of pore forming peptide action

Anna Mularski, Jonathan J Wilksch, Eric Hanssen, Richard A Strugnell, Frances Separovic

BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES | ELSEVIER | Published : 2016

Abstract

Time-resolved AFM images revealed that the antimicrobial peptide (AMP) caerin 1.1 caused localised defects in the cell walls of lysed Klebsiella pneumoniae cells, corroborating a pore-forming mechanism of action. The defects continued to grow during the AFM experiment, in corroboration with large holes that were visualised by scanning electron microscopy. Defects in cytoplasmic membranes were visualised by cryo-EM using the same peptide concentration as in the AFM experiments. At three times the minimum inhibitory concentration of caerin, 'pores' were apparent in the outer membrane. The capsule of K. pneumoniae AJ218 was unchanged by exposure to caerin, indicating that the ionic interaction ..

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Grants

Awarded by Australian Research Council


Awarded by National Health & Medical Research Council


Funding Acknowledgements

The authors gratefully acknowledge support from the Australian Research Council (Discovery Grant DP140102127), the National Health & Medical Research Council (Program Grant 606788) and Dr. Michelle Gee. AM received an Australian Postgraduate Award and a David Hay Postgraduate Writing Up Award (University of Melbourne). AFM work was performed in part at the Materials Characterization and Fabrication Platform (MCFP) at the University of Melbourne.