Molecular modeling of pathogenesis-related proteins of family 5.

The family of pathogenesis-related (PR) 5 proteins have diverse functions, and some of them are classified as thaumatins, osmotins, and inhibitors of alpha-amylase or trypsin. Although the specific function of many PR5 in plants is unknown, they are involved in the acquired systemic resistance and response to biotic stress, causing the inhibition of hyphal growth and reduction of spore germination, probably by a membrane permeabilization mechanism or by interaction with pathogen receptors. We have constructed three-dimensional models of four proteins belonging to the Rosaceae and Fagaceae botanical families by using the technique of comparative molecular modelling by homology. There are four main structural differences between all the PR5, corresponding to regions with replacements of amino acids. Folding and the secondary structures are very similar for all of them. However, the isoelectric point and charge distributions differ for each protein.