title: Multimerization of a Proline-Rich Antimicrobial Peptide, Chex-Arg20, Alters Its Mechanism of Interaction with the Escherichia coli Membrane.
abstract: A3-APO, a de novo designed branched dimeric proline-rich antimicrobial peptide (PrAMP), is highly effective against a variety of in vivo bacterial infections. We undertook a selective examination of the mechanism for the Gram-negative Escherichia coli bacterial membrane interaction of the monomer (Chex-Arg20), dimer (A3-APO), and tetramer (A3-APO disulfide-linked dimer). All three synthetic peptides were effective at killing E. coli. However, the tetramer was 30-fold more membrane disruptive than the dimer while the monomer showed no membrane activity. Using flow cytometry and high-resolution fluorescent microscopy, it was observed that dimerization and tetramerization of the Chex-Arg20 monomer led to an alteration in the mechanism of action from non-lytic/membrane hyperpolarization to membrane disruption/depolarization. Our findings show that the membrane interaction and permeability of Chex-Arg20 was altered by multimerization.
authors.affiliation: School of Chemistry, University of Melbourne, VIC 3010, Australia; The Florey Institute of Neuroscience and Mental Health, University of Melbourne, VIC 3010, Australia.
authors.forename: Wenyi
authors.initials: W
authors.lastname: Li
authors.affiliation: Oral Health CRC, Melbourne Dental School, University of Melbourne, VIC 3010, Australia; Bio21 Institute, University of Melbourne, VIC 3010, Australia.
authors.forename: Neil M
authors.initials: NM
authors.lastname: O'Brien-Simpson
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, University of Melbourne, VIC 3010, Australia.
authors.forename: Julien
authors.initials: J
authors.lastname: Tailhades
authors.affiliation: Oral Health CRC, Melbourne Dental School, University of Melbourne, VIC 3010, Australia.
authors.forename: Namfon
authors.initials: N
authors.lastname: Pantarat
authors.affiliation: Land Division, Defence Science and Technology Organization, Fishermans Bend, VIC 3207, Australia.
authors.forename: Raymond M
authors.initials: RM
authors.lastname: Dawson
authors.affiliation: Department of Biology, Temple University, Philadelphia, PA 19122, USA; Institute of Medical Microbiology, Semmelweis University, Budapest 1089, Hungary.
authors.forename: Laszlo
authors.initials: L
authors.lastname: Otvos
authors.affiliation: Oral Health CRC, Melbourne Dental School, University of Melbourne, VIC 3010, Australia; Bio21 Institute, University of Melbourne, VIC 3010, Australia.
authors.forename: Eric C
authors.initials: EC
authors.lastname: Reynolds
authors.affiliation: School of Chemistry, University of Melbourne, VIC 3010, Australia; Bio21 Institute, University of Melbourne, VIC 3010, Australia.
authors.forename: Frances
authors.initials: F
authors.lastname: Separovic
authors.affiliation: School of Chemistry, University of Melbourne, VIC 3010, Australia; The Florey Institute of Neuroscience and Mental Health, University of Melbourne, VIC 3010, Australia. Electronic address: akhter.hossain@florey.edu.au.
authors.forename: Mohammed Akhter
authors.initials: MA
authors.lastname: Hossain
authors.affiliation: School of Chemistry, University of Melbourne, VIC 3010, Australia; The Florey Institute of Neuroscience and Mental Health, University of Melbourne, VIC 3010, Australia. Electronic address: john.wade@florey.edu.au.
authors.forename: John D
authors.initials: JD
authors.lastname: Wade
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology*; D019281:Dimerization; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism*; D005434:Flow Cytometry; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008856:Microscopy, Fluorescence; D010455:Peptides / Q000138:chemical synthesis / Q000493:pharmacokinetics; D011392:Proline / Q000737:chemistry / Q000378:metabolism; D055232:Proline-Rich Protein Domains; D013329:Structure-Activity Relationship
chemical_list: D023181:Antimicrobial Cationic Peptides; D008565:Membrane Proteins; D010455:Peptides; D011392:Proline