Covalent Glycan Arrays

Covalently immobilized arrays are formatted by glycans with functionalized spacers that react with a complementary activated surface to form a covalent bond. Several different covalent interactions were reported to construct a specified glycan array. Amine chemistry and thiol chemistry are the two major methods to conjugate glycans to the reactive substrate in the array surface (Fig. 15.2). Thiol chemistry was first adapted by Injae Shin in 2002 to react with the maleimide functional group (Fig. 15.2a, b) [7,41 ]. Disulfide bond formation was then reported for the fabrication 

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J. Stevens, N. Razi, D.J. Stevens, J.J. Skehel, I. van Die, D.R. Burton, I.A. Wilson, R. Cummings, N. Bovin, C.-H. Wong, J.C. Paulson, Printed covalent glycan array for ligand profiling of diverse glycan binding proteins, Proc. Natl. Acad. Sci. U.S.A. 2004, 101, 17033-17038. 

H., and Paulson, J. C. (2004) Printed covalent glycan array for ligand profiling of diverse glycan binding proteins Proc Natl Acad Sci USA 101, 17033-8. 

Blixt O, Head S, Mondala T, Scanlan C, Huflejt ME, Alvarez R, Bryan MC, Fazio F, Calarese D, Stevens J, Razi N, Stevens DJ, Skehel JJ, van Die I, Burton DR, Wilson lA, Cummings R, Bovin N, Wong CH, Paulson JC. Printed covalent glycan array for ligand profiling of diverse glycan binding proteins. Proc Natl Acad Sci USA 2004 101 17033-17038. 

In the more abundant a chitin the chains in alternate sheets have opposite orientations,101102 possibly a result of hairpin folds in the strands. Native chitin exists as microfibrils of 7.25 nm diameter. These contain a 2.8-nm core consisting of 15-30 chitin chains surrounded by a sheath of 27-kDa protein subunits. The microfibrils pack in a hexagonal array, but the structure is not completely regular. Several proteins are present some of the glucosamine units of the polysaccharide are not acetylated and the chitin core is often calcified.103 The commercial product chitosan is a product of alkaline deacetylation of chitin but it also occurs naturally in some fungi.102 Chitin is also present in cell walls of yeasts and other fungi. It is covalently bonded to a P-l,3-linked glycan which may, in turn, be linked to a mannoprotein (see Section D,2)97... 

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