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Membrane binding and perturbation studies of the antimicrobial peptides caerin, citropin, and maculatin
Author(s) -
Brian Chia C. S.,
Gong Yujing,
Bowie John H.,
Zuegg Johannes,
Cooper Matthew A.
Publication year - 2011
Publication title -
peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.21438
Subject(s) - chemistry , membrane , vesicle , surface plasmon resonance , antibacterial activity , minimum inhibitory concentration , lipid bilayer , escherichia coli , bacteria , antimicrobial peptides , biochemistry , biophysics , stereochemistry , peptide , in vitro , nanoparticle , biology , nanotechnology , materials science , gene , genetics
Abstract Citropin 1.1, maculatin 1.1, and caerin 1.1 are short antibacterial cationic peptides from the skin glands of the Australian tree frog Litoria species. Several analogues have been synthesized to give a better insight into the relationship between the structure of the peptides and their antibacterial and haemolytic activity. Binding studies using a surface plasmon resonance (SPR) biosensor together with a vesicle‐capture sensor chip have been used to investigate selectivity of the peptides and their analogues for 1,2‐dimyristoyl‐sn‐glycero‐3‐phosphoglycerol (DMPG) and 1,2‐dimyristoyl‐sn‐glycero‐3‐phosphocholine (DMPC) vesicles, as well as for vesicles made from lipid extracts from Escherichia coli and bovine brain. Data obtained for membrane selectivity using natural lipid extracts show better correlation with minimum inhibitory concentration (MIC) values against Gram‐positive bacteria and haemolytic activity than that obtained using synthetic DMPG and DMPC. Electron microscopy and membrane leakage studies using Gram‐positive bacteria gave further insight into the membrane disruption properties of the peptides. For maculatin 1.1, it was found that the central proline residue, which is responsible for a bend in the α‐helical structure, is essential not only for the antibacterial activity but also for binding, and perturbation of membranes. The caerin analogues showed only small variations in their MIC values and membrane binding. In contrast, for citropin 1.1, the analogue replacing the aspartate with a lysine showed the lowest MIC against Gram‐positive bacteria and best membrane binding to E. coli lipid extracts, coinciding with an increased hydrophobic moment of the peptide. These data give further insight into these antimicrobial natural products, toward the development and evaluation of these and other analogues as potential antibiotics. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 96:147–157, 2011.