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.
|
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. |