title: Antifungal properties of Canavalia ensiformis urease and derived peptides.
abstract: Ureases (EC 3.5.1.5) are metalloenzymes that hydrolyze urea into ammonia and CO(2). These proteins have insecticidal and fungicidal effects not related to their enzymatic activity. The insecticidal activity of urease is mostly dependent on the release of internal peptides after hydrolysis by insect digestive cathepsins. Jaburetox is a recombinant version of one of these peptides, expressed in Escherichia coli. The antifungal activity of ureases in filamentous fungi occurs at submicromolar doses, with damage to the cell membranes. Here we evaluated the toxic effect of Canavalia ensiformis urease (JBU) on different yeast species and carried out studies aiming to identify antifungal domain(s) of JBU. Data showed that toxicity of JBU varied according to the genus and species of yeasts, causing inhibition of proliferation, induction of morphological alterations with formation of pseudohyphae, changes in the transport of H(+) and carbohydrate metabolism, and permeabilization of membranes, which eventually lead to cell death. Hydrolysis of JBU with papain resulted in fungitoxic peptides (~10 kDa), which analyzed by mass spectrometry, revealed the presence of a fragment containing the N-terminal sequence of the entomotoxic peptide Jaburetox. Tests with Jaburetox on yeasts and filamentous fungi indicated a fungitoxic activity similar to ureases. Plant ureases, such as JBU, and its derived peptides, may represent a new alternative to control medically important mycoses as well as phytopathogenic fungi, especially considering their potent activity in the range of 10(-6)-10(-7)M.
authors.affiliation: Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Melissa
authors.initials: M
authors.lastname: Postal
authors.forename: Anne H S
authors.initials: AH
authors.lastname: Martinelli
authors.forename: Arlete B
authors.initials: AB
authors.lastname: Becker-Ritt
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Ligabue-Braun
authors.forename: Diogo R
authors.initials: DR
authors.lastname: Demartini
authors.forename: Suzanna F F
authors.initials: SF
authors.lastname: Ribeiro
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Pasquali
authors.forename: Valdirene M
authors.initials: VM
authors.lastname: Gomes
authors.forename: Celia R
authors.initials: CR
authors.lastname: Carlini
mesh_terms: D000595:Amino Acid Sequence; D000935:Antifungal Agents / Q000494:pharmacology*; D032449:Canavalia / Q000737:chemistry*; D050260:Carbohydrate Metabolism / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D004353:Drug Evaluation, Preclinical; D005658:Fungi / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D006868:Hydrolysis; D008969:Molecular Sequence Data; D010206:Papain / Q000737:chemistry; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D017434:Protein Structure, Tertiary; D014510:Urease / Q000737:chemistry / Q000494:pharmacology*; D015003:Yeasts / Q000187:drug effects
chemical_list: D000935:Antifungal Agents; D010446:Peptide Fragments; D010940:Plant Proteins; D010206:Papain; D014510:Urease; D005947:Glucose