Estudos de inibição e modelagem por homologia da enzima beta(1,3)-d-glicano sintase de moniliophthora perniciosa

Abstract

The Witches’ Broom Disease, caused by the hemibiotrophic basidiomycete fungus Moniliophthora perniciosa, drastically reduced the production of cocoa in Brazil. M. perniciosa colonize meristematic tissues decreasing the productivity and the lifetime of the host plant. Efforts have been expended to elucidate the molecular targets, such as beta(1,3)-D-glucan synthase, a glycosyltransferase that is essential for the cell wall construction, this enzyme catalyzes the formation of 1,3-β-D-glycans structural compounds. Bioinformatics methods are able to determine the structure of proteins without performing experimental steps, considering the barriers related to experimental methods for structure determination of molecular targets. Therefore, the objective of this study was determine the three-dimensional model of the enzyme beta(1,3)-D-glucan synthase of M. perniciosa by homology modeling and study the micelial growth inhibiting of the fungus by organics compounds and vegetal extracts with potential use in cocoa plantation. To build the models, was implemented both procedures: a comparative modeling by satisfaction of spatial restraints in MODELLER and a modeling by assembly of rigid bodies in the SWISS-MODEL software. Was obtained reasonable for beta(1,3)-D-glucan synthase enzyme (BegS1), agree well with general structure from GT-2 enzyme family. In studies of fungal inhibiting growth, the MIC was considered one which there was 100% inhibition of mycelial growth. Extracts derived from Lippia alnifolia and the substance HQN showed promising results with MIC lowest values for M. perniciosa fungus.