title: New insights into the structure and mode of action of Mo-CBP3, an antifungal chitin-binding protein of Moringa oleifera seeds.
abstract: Mo-CBP3 is a chitin-binding protein purified from Moringa oleifera Lam. seeds that displays inhibitory activity against phytopathogenic fungi. This study investigated the structural properties and the antifungal mode of action of this protein. To this end, circular dichroism spectroscopy, antifungal assays, measurements of the production of reactive oxygen species and microscopic analyses were utilized. Mo-CBP3 is composed of 30.3% α-helices, 16.3% β-sheets, 22.3% turns and 30.4% unordered forms. The Mo-CBP3 structure is highly stable and retains its antifungal activity regardless of temperature and pH. Fusarium solani was used as a model organism for studying the mechanisms by which this protein acts as an antifungal agent. Mo-CBP3 significantly inhibited spore germination and mycelial growth at 0.05 mg.mL-1. Mo-CBP3 has both fungistatic and fungicidal effects, depending on the concentration used. Binding of Mo-CBP3 to the fungal cell surface is achieved, at least in part, via electrostatic interactions, as salt was able to reduce its inhibitory effect. Mo-CBP3 induced the production of ROS and caused disorganization of both the cytoplasm and the plasma membrane in F. solani cells. Based on its high stability and specific toxicity, with broad-spectrum efficacy against important phytopathogenic fungi at low inhibitory concentrations but not to human cells, Mo-CBP3 has great potential for the development of new antifungal drugs or transgenic crops with enhanced resistance to phytopathogens.
authors.affiliation: Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors.forename: Adelina B
authors.initials: AB
authors.lastname: Batista
authors.affiliation: Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors.forename: José T A
authors.initials: JT
authors.lastname: Oliveira
authors.affiliation: Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors.forename: Juliana M
authors.initials: JM
authors.lastname: Gifoni
authors.affiliation: Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors.forename: Mirella L
authors.initials: ML
authors.lastname: Pereira
authors.affiliation: Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors.forename: Marina G G
authors.initials: MG
authors.lastname: Almeida
authors.affiliation: Bioscience and Biotecnology Center, State University of North Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil.
authors.forename: Valdirene M
authors.initials: VM
authors.lastname: Gomes
authors.affiliation: Bioscience and Biotecnology Center, State University of North Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil.
authors.forename: Maura
authors.initials: M
authors.lastname: Da Cunha
authors.affiliation: Bioscience and Biotecnology Center, State University of North Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil.
authors.forename: Suzanna F F
authors.initials: SF
authors.lastname: Ribeiro
authors.affiliation: Bioscience and Biotecnology Center, State University of North Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil.
authors.forename: Germana B
authors.initials: GB
authors.lastname: Dias
authors.affiliation: Physics Institute of São Carlos, University of São Paulo, São Carlos, São Paulo, Brazil.
authors.forename: Leila M
authors.initials: LM
authors.lastname: Beltramini
authors.affiliation: Physics Institute of São Carlos, University of São Paulo, São Carlos, São Paulo, Brazil.
authors.forename: José Luiz S
authors.initials: JL
authors.lastname: Lopes
authors.affiliation: Department of Biology, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors.forename: Thalles B
authors.initials: TB
authors.lastname: Grangeiro
authors.affiliation: Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors.forename: Ilka M
authors.initials: IM
authors.lastname: Vasconcelos
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry* / Q000494:pharmacology; D002686:Chitin / Q000378:metabolism*; D020231:Colletotrichum / Q000187:drug effects; D005670:Fusarium / Q000187:drug effects; D029588:Moringa oleifera / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry* / Q000494:pharmacology; D011485:Protein Binding; D055550:Protein Stability; D012639:Seeds / Q000737:chemistry; D013172:Spores, Fungal / Q000187:drug effects
chemical_list: D000935:Antifungal Agents; D010940:Plant Proteins; D002686:Chitin