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Molecules 2018, 23(4), 952;

Chemical Synthesis and Functional Analysis of VarvA Cyclotide

Laboratorio de Fisiología y Genética Marina (FIGEMA), Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Coquimbo 1781421, Chile
Facultad de Ciencias del Mar, Universidad Católica del Norte, Coquimbo 1781421, Chile
Centro AquaPacífico, Coquimbo 1781421, Chile
Núcleo de Biotecnología de Curauma, Pontificia Universidad Católica de Valparaíso, Valparaíso 2373223, Chile
Department of Organic Chemistry and CIBER-BBN, Networking Centre on Bioengineering, Biomaterials and Nanomedicine, University of Barcelona, Barcelona 08007, Spain
School of Chemistry, University of KwaZulu-Natal, Durban 4001, South Africa
Author to whom correspondence should be addressed.
Received: 29 March 2018 / Revised: 14 April 2018 / Accepted: 17 April 2018 / Published: 19 April 2018
(This article belongs to the Special Issue Cyclic Peptides)
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Cyclotides are circular peptides found in various plant families. A cyclized backbone, together with multiple disulfide bonds, confers the peptides’ exceptional stability against protease digestion and thermal denaturation. In addition, the features of these antimicrobial molecules make them suitable for use in animal farming, such as aquaculture. Fmoc solid phase peptide synthesis on 2-chlorotrityl chlorine (CTC) resin using the “tea-bag” approach was conducted to generate the VarvA cyclotide identified previously from Viola arvensis. MALDI-TOF mass spectrometry determined the correct peptide amino acid sequence and the cyclization sites-critical in this multicyclic compound. The cyclotide showed antimicrobial activity against various Gram-negative bacteria, including recurrent pathogens present in Chilean aquaculture. The highest antimicrobial activity was found to be against Flavobacterium psychrophilum. In addition, membrane blebbing on the bacterial surface after exposure to the cyclotide was visualized by SEM microscopy and the Sytox Green permeabilization assay showed the ability to disrupt the bacterial membrane. We postulate that this compound can be proposed for the control of fish farming infections. View Full-Text
Keywords: cyclotide; antimicrobial activity; fish pathogens; membrane damage cyclotide; antimicrobial activity; fish pathogens; membrane damage

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Álvarez, C.A.; Santana, P.A.; Luna, O.; Cárdenas, C.; Albericio, F.; Romero, M.S.; Guzmán, F. Chemical Synthesis and Functional Analysis of VarvA Cyclotide. Molecules 2018, 23, 952.

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