Roger Bretthauer, Professor (Emeritus)

Professor Bretthauer's research is concerned with the structure, metabolism and function of glycoproteins of eucaryotes. Research efforts are focused mainly on the carbohydrate moieties that are covalently bound to asparagine residues (N-linked) and to serine and threonine residues (O-linked) of the protein moieties of glycoproteins. The N-linked oligosaccharide originates from a common precursor oligosaccharide that is assembled in the endoplasmic reticulum on a lipid carrier, dolichol phosphate, and that is then transferred in a cotranslational event to a particular asparagine residue of the protein. Recent aspects of this research involve investigations of glycoprotein processing reactions by which the final oligosaccharide structure of the mature glycoprotein is formed from the original oligosaccharide that was donated to the protein from the dolichol carrier. The particular amino acid sites of O-glycosylation and the structures of the O-linked saccharides are also being investigated. There is particular interest in understanding N- and O-linked protein glycosylation reactions in lower eucaryotes where less highly processed glycoproteins are found. Current studies are focused on these reactions in cultured cells, such as insects and yeasts, that are utilized for expression of heterologous recombinant proteins. These studies involve structural analyses of the protein-bound saccharides (N- and O-linked) and isolation and characterization of particular processing enzymes. Regulatory features and genetic alteration of these enzymes are also of interest.