Panusin represents a new family of b-defensin-like peptides in invertebrates Vivian Montero-Alejo a, * , Gerardo Corzo b , Javier Porro-Suardíaz a , Zenia Pardo-Ruiz a , Erick Perera c , Leandro Rodríguez-Viera d , Gabriela S  anchez-Díaz e, f , Erix Wiliam Hern  andez-Rodríguez e, f , Carlos  Alvarez g , Steve Peigneur h , Jan Tytgat h , Rolando Perdomo-Morales a, ** a Biochemistry Department, Center for Pharmaceuticals Research and Development, Havana, Cuba b Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Aut onoma de M exico, Mexico c Department of Fish Physiology and Biotechnology, Institute of Aquaculture Torre de la Sal (IATS-CSIC), Castell on, Spain d Center for Marine Research, University of Havana, Havana, Cuba e Department for Basic and Biomedical Sciences, Medicine Faculty, Artemisa, Cuba f Laboratory of Computational and Theoretical Chemistry, University of Havana, Havana, Cuba g Center for Protein Studies, Faculty of Biology, University of Havana, Havana, Cuba h Toxicology and Pharmacology, University of Leuven (KU Leuven), Leuven, Belgium article info Article history: Received 21 July 2016 Received in revised form 5 September 2016 Accepted 6 September 2016 Available online xxx Keywords: Invertebrate Antimicrobial activity Secondary structure Protein purification Membrane binding Defensins abstract Beta_defensin have been solely found in vertebrates until b-defensin-like peptides were described as transcript isoforms in two species of Panulirus genus. They were considered as putative antimicrobials since their biological activity have not been demonstrated. Here we purified and characterized a defensin-like peptide from the hemocytes of spiny lobster P. argus, hereafter named panusin. Structurally, panusin presents a cysteine-stabilized a/b motif, and is prone to form homodimers. Biological activity of panusin showed broad-spectrum antimicrobial activity, characterized for being strikingly salt-resistant. Panusin did not showed hemolytic activity but was demonstrated its binding capacity to different lipid membrane models, indicating amphipathicity of b-sheet core as driving force for its antimicrobial ac- tivity. Panusin is considered a new kind of arthropod defensin which share structural and biological features with beta-defensin from vertebrates. The presence of beta-defensin like peptides in crustacean might suggest the emergence of the evolutionary relationship of b-defensins from vertebrates. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Antimicrobial peptides (AMPs) are included among the so called host-defense peptides (HDPs), which are main components of the innate immune response in both vertebrate and invertebrate or- ganisms (Hancock et al., 2006). Defensins have become essential HDPs since they are found in a wide range of taxonomical groups, suggesting that these peptides have derived from a common ancestor and their function conserved across evolution (Yount and Yeaman, 2004). Evolutionary relationship between invertebrate and vertebrate defensins remains unclear despite sequence and structure analyses revealed that both families show a close rela- tionship between statistical alignment parameters and conforma- tional features (Tassanakajon et al., 2015). Invertebrate defensins have been classified in subfamilies based on their biological prop- erties, e.g. anti-bacterial versus anti-fungal activity (Bulet et al., 2004). Together with fungi and plants defensins, they adopt the cysteine stabilized a-helical and b-sheet folds (CSab). Arthropod and mollusk-type 6-cysteine defensins are the major group of invertebrate defensins, being the insect defensins the most studied among arthropods. Insect defensins, represented by defensin A, are 35e45 residues long and have an overall structural fold that is * Corresponding author. Biochemistry Department, Center for Pharmaceuticals Research and Development, Ave. 26 No. 1605, Plaza de la Revoluci on, CP 10600, Habana, Cuba. ** Corresponding author. Biochemistry Department, Center for Pharmaceuticals Research and Development, Ave. 26 No. 1605, Plaza de la Revoluci on, CP 10600, Habana, Cuba. E-mail addresses: vivian.montero@fq.uh.cu (V. Montero-Alejo), rolando. perdomo@infomed.sld.cu (R. Perdomo-Morales). Contents lists available at ScienceDirect Developmental and Comparative Immunology journal homepage: www.elsevier.com/locate/dci http://dx.doi.org/10.1016/j.dci.2016.09.002 0145-305X/© 2016 Elsevier Ltd. All rights reserved. Developmental and Comparative Immunology xxx (2016) 1e12 Please cite this article in press as: Montero-Alejo, V., et al., Panusin represents a new family of b-defensin-like peptides in invertebrates, Developmental and Comparative Immunology (2016), http://dx.doi.org/10.1016/j.dci.2016.09.002