Glycobiology

In the recent past, biomedical scientists have been primarily concerned with intracellular events at the genetic and protein levels. Recently, a wealth of new information has revealed that extracellular environment exert tremendous influences in normal and aberrant pathophysiology. Our efforts are thus largely associated with a third class of important biomolecules that occur extracellularly—the glycans.

Carbohydrates are indispensable to life on Earth. In their simplest form, they serve as a primary energy source for sustaining life. Most carbohydrates exist however not as simple sugars but as complex molecular conjugates, called glycans, which are ubiquitous in the human body, resident on and between virtually every cell surface. Although nucleic acids and proteins have traditionally tended to attract far more attention, glycans are also key to life. In the new millennium it is likely that the advancement of glycobiology will be critical in elucidating the importance of all three of these classes of biomolecules -- so much so, that we suggest the traditional framework -- ‘The Central Dogma of Biology’ -- has been revisited. With the human genome project virtually complete, many scientists were baffled to find that there exist a limited group of genes in the human code of life. This confusion can be alleviated throughthe understanding that glycan-based regulation of cellular genotype greatly multiplies potential on the level of phenotypic expression.

Extracellular Environment: Biological inquiry at the intracellular level has long been a central focus of life scientists. In order for scientific inquiry to evolve to the inherently greater rigor of a systems biology approach, an understanding of extracellular biological phenomena is also required.

Glycan Structure & Complexity: The information content of biomolecules, inherent according to their structure, is of a phenomenal scale in glycans. This becomes evident when noting that DNA comprises four bases, proteins 20 amino acids, and (for example) glycosaminoglycans are composed of 48 distinct building blocks.

Glycan Biosynthesis: Glycans play such a pivotal role in biology that it is worthwhile to consider just how the structural diversity that governs their function actually develops. The chemical complexity that allows these biopolymers to control so many essential life functions is the result of a system of intricate molecular machines, each of which put in place a particular structural element of the polymer chain.
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Biological Interactions: Glycan structure governs myriad interactions between important biological players which effects the cell function in both normal and aberrant pathophysiological states.

Glycan Catabolism: Just as polysaccharides are synthesized by intricate biological and chemical processes, they are also degraded as part of normal turnover events. The cellular degradation of glycans represents a cluster of critical biological pathways, essential for the continued proper functioning of the organism as a whole.