Protein glycosylation: new challenges and opportunities.

Protein glycosylation is the most complex post-translational modification process. More than 50% of proteins in humans are glycosylated, while bacteria such as E. coli does not have this modification machinery. Many small-molecule natural products also require glycosylation in order to express their function. Development of effective synthetic tools for use in understanding the effect of glycosylation on the structure and function of biomolecules will lead to the development of new strategies to tackle major problems associated with carbohydrate-mediated biological recognitions.