Ion channel-like activity of the antimicrobial peptide tritrpticin in planar lipid bilayers

Ion channel-like activity of the antimicrobial peptide tritrpticin in planar lipid bilayers

Author Salay, L. C. Google Scholar
Procopio, J. Google Scholar
Oliveira, Eliandre Autor UNIFESP Google Scholar
Nakaie, Clovis Ryuichi Autor UNIFESP Google Scholar
Schreier, S. Google Scholar
Institution Universidade de São Paulo (USP)
Universidade Federal de São Paulo (UNIFESP)
Abstract The cationic peptide tritrpticin (VRRFPWWWPFLRR, Trp3) has a broad action spectrum, acting against Gram-positive and Gram-negative bacteria, as well as some fungi, while also displaying hemolytic activity. We have studied the behavior of Trp3 in planar lipid bilayers (or black lipid membrane-BLM) and were able to demonstrate its ion channel-like activity. Channel-like activity was observed in negatively charged azolectin BLM as a sudden appearance of discrete current fluctuations upon application of a constant voltage across the membrane. Trp3 formed large conductance channels (500-2000 pS) both at positive and negative potentials. in azolectin bilayers, the predominant ion-channel activity was characterized by very regular and discrete current steps (corresponding to openings) of uniform amplitude, which exhibited relatively long residence times (of the order of seconds). Occasionally, multiple conductance steps were observed, indicating the simultaneous presence of more than one open pore. in bilayers of zwitterionic diphytanoylphosphatidyl choline (DPhk) Trp3 also showed ion-channel activity, but in a much less frequent and less prominent way. Studies of ion selectivity indicated that Trp3 forms a cation-selective channel. These results should contribute to the understanding of the molecular interactions and mechanism of action of Trp3 in lipid bilayers and biological membranes. (C) 2004 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
Keywords tritrpticin
antimicrobial peptide
ion channel
black lipid membrane
planar lipid membrane
Language English
Date 2004-05-01
Published in Febs Letters. Amsterdam: Elsevier B.V., v. 565, n. 1-3, p. 171-175, 2004.
ISSN 0014-5793 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 171-175
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000221397400033

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