The role of spatial and electronic structure, hydrophobic properties and concentration of organoselenium compounds on their interaction with fungal metabolites - carbohydrate-binding proteins, extracellular lectins of Lentinula edodes (shiitake mushroom) has been consi dered. By the hybrid density functional theory method at the B3LYP/6-31G(d,p) theory level, spatial and electronic structure of the 1,5-di(4-R-phenyl)-3-selenopentanediones-1,5 molecules has been studied.