Glycoconjugates strategy

Using the same versatile modular synthetic strategy, the same group developed biotinylated bi- (438) and tetra-antennary (439) mannosylated glycoconjugates to capture and detect E. coli cells, and compared the relative capturing ability of these molecules to commercial polyclonal antibodies (Fig. 47).318 Instead of aliphatic spacers, tetraethylene glycol linkers were used to diminish nonspecific binding and to impart flexibility for a better fit in the active sites. 

This simple strategy can be used to add amine residues to polysaccharide molecules after formation of aldehydes by periodate or enzymatic oxidation (Section 4.4, this chapter). Thus, glycoconjugates or carbohydrate polymers such as dextran may be derivatized to contain amines for further conjugation reactions. 

Koeller KM, Wong C-H (2000) Synthesis of complex carbohydrates and glycoconjugates enzyme-based and programmable one-pot strategies. Chem Rev 100 4465 1494... 

The introduction of the chemical handle needed (azide or alkyne) can be achieved by means of indiscriminate functiona.liza.tion of natural amino acids (via Lys [128-131] or Cys [129]) or by genetic incorporation. The latter strategy permits the preparation of more precisely defined glycoconjugates. One comparison of the two methods was... 

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