Speaker: Olga Zabotina, Department of Biochemistry, Biophysics and Molecular Biology - Iowa State University

Title: “Plant polysaccharide biosynthesis: What have we learned about xyloglucan so far?” 

Abstract: Our research goal is to understand the mechanism of polysaccharide biosynthesis in plant Golgi. Our cell biology and biochemical studies demonstrated that formation of multiprotein complex is required to synthesize xyloglucan, the highly branched hemicellulose polysaccharide in all plant cell walls. Recently we obtained the crystal structure of xyloglucan xylosyltransferase 1 (XXT1), which is only a second structure available for any of plant cell wall polysaccharide synthesizing enzymes, after fucosyltransferase 1 reported three years ago. The XXT1 structure and homology models of other two essential xylosyltransferases XXT2 and XXT5 allowed us to propose the reasonable model of how glucan synthase CSLC4 and three XXTs are organized in a single complex to synthesize the native patterns of plant xyloglucan. Currently we continue to pursue several complementary directions towards understanding the functional organization of this large xyloglucan synthesizing complex and the mechanism of its action using multidisciplinary approaches