Structural Requirements for the Binding of Phenylglycosides to the Surface of Protoplasts

Abstract
A variety of phenylglycosides have been synthesized and tested for binding to the surface of protoplasts from suspension-cultured cells of "Paul''s Scarlet" rose (Rosa sp.). Multivalent phenylglycosides in the form of Yariv antigens (1,3,5-tri-[p-glycosyloxyphenylazo]-2,4,6-trihydroxybenzene) agglutinated the protoplasts. Fluorescence-labeled derivatives of other monovalent and polyvalent phenyl-.beta.-glycosides did not bind to the protoplast surface. Agglutination was induced by Yariv antigens only if these probes contained .beta.-anomeric, O-glycosidic linkages. Yariv antigens containing .alpha.-anomeric or thio-glycosidic linkages did not agglutinate protoplasts. These same structural features of Yariv antigens were also required for the precipitation of gum arabic-Yariv antigen complexes. The results suggest that plasma membranes of "Paul''s Scarlet" rose protoplasts contain arabinagalactan-proteins that interact with phenyl-.beta.-glycosides. The results further show that binding at these plasma membrane sites is not solely dependent upon the carbohydrate portion of single phenylglycosides, but may also require specific spatial orientations of adjacent phenylglycosides.