The Polygalacturonase-Inhibiting Protein PGIP2 of Phaseolus vulgaris Has Evolved a Mixed Mode of Inhibition of Endopolygalacturonase PG1 of Botrytis cinerea
| Autor: | Demetrius Tsernoglou, Luca Federici, Giulia De Lorenzo, C. Caprari, Juan Fernández-Recio, Felice Cervone, Francesca Sicilia |
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| Rok vydání: | 2005 |
| Předmět: |
Models
Molecular Protein Conformation Physiology Plant Science Cell wall Genetics Plant defense against herbivory Homology modeling Pectinase Plant Proteins Botrytis cinerea Phaseolus Binding Sites biology food and beverages Active site biology.organism_classification Kinetics Polygalacturonase Biochemistry Docking (molecular) Mutation biology.protein Botrytis Protein Binding Research Article |
| Zdroj: | Plant Physiology. 139:1380-1388 |
| ISSN: | 1532-2548 0032-0889 |
| Popis: | Botrytis cinerea is a phytopathogenic fungus that causes gray mold in >1,000 plant species. During infection, it secretes several endopolygalacturonases (PGs) to degrade cell wall pectin, and among them, BcPG1 is constitutively expressed and is an important virulence factor. To counteract the action of PGs, plants express polygalacturonase-inhibiting proteins (PGIPs) that have been shown to inhibit a variety of PGs with different inhibition kinetics, both competitive and noncompetitive. The PG-PGIP interaction promotes the accumulation of oligogalacturonides, fragments of the plant cell wall that are general elicitors of plant defense responses. Here, we characterize the enzymatic activity of BcPG1 and investigate its interaction with PGIP isoform 2 from Phaseolus vulgaris (PvPGIP2) by means of inhibition assays, homology modeling, and molecular docking simulations. Our results indicate a mixed mode of inhibition. This is compatible with a model for the interaction where PvPGIP2 binds the N-terminal portion of BcPG1, partially covering its active site and decreasing the enzyme affinity for the substrate. The structural framework provided by the docking model is confirmed by site-directed mutagenesis of the residues that distinguish PvPGIP2 from the isoform PvPGIP1. The finding that PvPGIP2 inhibits BcPG1 with a mixed-type kinetics further indicates the versatility of PGIPs to evolve different recognition specificities. |
| Databáze: | OpenAIRE |
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