Characterization of a defensin from the oyster Crassostrea gigas. Recombinant production, folding, solution structure, antimicrobial activities, and gene expression.

• Published in: Journal of Biological Chemistry
• Main Authors: Gueguen, Yannick, Herpin, Amaury, Aumelas, André, Garnier, Julien, Fievet, Julie, Escoubas, Jean-Michel, Bulet, Philippe, Gonzalez, Marcelo, Lelong, Christophe, Favrel, Pascal, Bachère, Evelyne
• Other Authors: Génome, populations, interactions, adaptation (GPIA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Atheris Laboratories, Departamento de Tecnología Electrónica, Universidade de Vigo, Centre hépato-biliaire (CHB), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpital Paul Brousse-Institut National de la Santé et de la Recherche Médicale (INSERM), Bureau de Recherches Géologiques et Minières (BRGM), Departamento de Literatura Española e Hispanoamericana, Universidad de Salamanca, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Paul-Valéry - Montpellier 3 (UPVM), Departamento de Optica y Fisica Aplicada, Universidad de Valladolid Valladolid (UVa)-Facultad de Ciencias, Laboratorio de Bioinformática y Expresión Génica, Laboratoire de psychologie cognitive (LPC), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Biochimie et biophysique des systèmes intégrés (BBSI), Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Adaptation et pathogénie des micro-organismes Grenoble (LAPM), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: Escherichia coli; amino acid sequence; animals; defensins; gene Expression; gram-negative bacteria; gram-positive bacteria; molecular sequence data; nuclear magnetic resonance; biomolecular; protein folding; protein structure; recombinant proteins; MESH: Amino Acid Sequence; MESH: Animals; MESH: Gram-Negative Bacteria; MESH: Gram-Positive Bacteria; MESH: Molecular Sequence Data; MESH: Nuclear Magnetic Resonance; MESH: Protein Folding; MESH: Protein Structure; Secondary; Tertiary; MESH: Recombinant Proteins; MESH: Crassostrea; MESH: Defensins; MESH: Escherichia coli; MESH: Gene Expression; [SDV.BBM]Life Sciences [q-bio]/Biochemistry; Molecular Biology; Crassostrea gigas
• Online Access: https://hal.science/hal-00286204; https://hal.science/hal-00286204/document; https://hal.science/hal-00286204/file/2006_Gueguen_Journal%20of%20Biological%20Chemistry_1.pdf; https://doi.org/10.1074/jbc.M510850200

International audience In invertebrates, defensins were found in arthropods and in the mussels. Here, we report for the first time the identification and characterization of a defensin (Cg-Def) from an oyster. Cg-def mRNA was isolated from Crassostrea gigas mantle using an expressed sequence tag approach. To gain insight into potential roles of Cg-Def in oyster immunity, we produced the recombinant peptide in Escherichia coli, characterized its antimicrobial activities, determined its solution structure by NMR spectroscopy, and quantified its gene expression in vivo following bacterial challenge of oysters. Recombinant Cg-Def was active in vitro against Gram-positive bacteria but showed no or limited activities against Gram-negative bacteria and fungi. The activity of Cg-Def was retained in vitro at a salt concentration similar to that of seawater. The Cg-Def structure shares the so-called cystine-stabilized alpha-beta motif (CS-alphabeta) with arthropod defensins but is characterized by the presence of an additional disulfide bond, as previously observed in the mussel defensin (MGD-1). Nevertheless, despite a similar global fold, the Cg-Def and MGD-1 structures mainly differ by the size of their loops and by the presence of two aspartic residues in Cg-Def. Distribution of Cg-def mRNA in various oyster tissues revealed that Cg-def is mainly expressed in mantle edge where it was detected by mass spectrometry analyses. Furthermore, we observed that the Cg-def messenger concentration was unchanged after bacterial challenge. Our results suggest that Cg-def gene is continuously expressed in the mantle and would play a key role in oyster by providing a first line of defense against pathogen colonization.