Simple synthesis of protein-oligosaccharide conjugates as tools for diverse bio-applications

MALENA LANDONI; JOSÉ KOVENSKY; ALICIA S. COUTO

Córdoba- Argentina

Congreso; XLIV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2008

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Due to the haptenic nature of sugars, preparation of an immunogen with a carrier protein is often necessary.  In the last years several approaches have been developed:  coupling of a conveniently derivatized sugar to an aminoacid followed by automatic peptide synthesis, coupling of sugars to gold nanoparticules, glycosides functionalized with an electrophilic thiol specific reagent for immobilization by disulfide bonds to the protein. However, all these methods involve several steps of organic synthesis prior to the coupling reaction making it time-consuming and rather expensive.      In this work we present a method of preparing amino derivative sugars and an easy way to couple them to commercial proteins.  We have performed the coupling reaction to bovine serum albumin using different oligosaccharides. Conjugates were tested by SDS-PAGE and characterized by UV-MALDI-TOF mass spectrometry analysis. Different reaction conditions were tried changing the reaction time, temperature and protein/sugar molar ratio. Best conditions yielded a BSA-modified conjugate bearing eleven sugar units. This approach allows the fast and cheap preparation of a wide variety of pseudo-glycoproteins by changing the peptide moiety and/or the sugar unit making it a potential and useful tool for different bio-applications such as antibody production and immunoassays.