Cyclotide Evolution: Insights from the Analyses of Their Precursor Sequences, Structures and Distribution in Violets (Viola)
ORIGINAL RESEARCH published: 18 December 2017 doi: 10.3389/fpls.2017.02058 Cyclotide Evolution: Insights from the Analyses of Their Precursor Sequences, Structures and Distribution in Violets (Viola) Sungkyu Park 1, Ki-Oug Yoo 2, Thomas Marcussen 3, Anders Backlund 1, Erik Jacobsson 1, K. Johan Rosengren 4, Inseok Doo 5 and Ulf Göransson 1* 1 Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden, 2 Department of Biological Sciences, Kangwon National University, Chuncheon, South Korea, 3 Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, Oslo, Norway, 4 School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia, 5 Biotech Research Team, Biotech Research Center of Dong-A Pharm Co Ltd., Seoul, South Korea Cyclotides are a family of plant proteins that are characterized by a cyclic backbone and a knotted disulfide topology. Their cyclic cystine knot (CCK) motif makes them exceptionally resistant to thermal, chemical, and enzymatic degradation. By disrupting Edited by: cell membranes, the cyclotides function as host defense peptides by exhibiting Luis Valledor, Universidad de Oviedo, Spain insecticidal, anthelmintic, antifouling, and molluscicidal activities. In this work, we provide Reviewed by: the first insight into the evolution of this family of plant proteins by studying the Jesús Pascual Vázquez, Violaceae, in particular species of the genus Viola. We discovered 157 novel precursor University of Turku, Finland Diego Mauricio Riaño-Pachón, sequences by the transcriptomic analysis of six Viola species: V. albida var. takahashii, V. Institute of Chemistry, University of mandshurica, V. orientalis, V. verecunda, V. acuminata, and V. canadensis. By combining São Paulo, Brazil these precursor sequences with the phylogenetic classification of Viola, we infer the Monica Escandon, University of Aveiro, Portugal distribution of cyclotides across 63% of the species in the genus (i.e., ∼380 species).
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