Protein structure influences all aspects biological function.
Although there is considerable variation in the structural
motifs observed in biological macromolecules they
are all unified by being built from the same 20 amino
acids. The differences are due to the essentially infinite
number of protein sequences that may be generated from
these building blocks. At a fundamental level, rigorous
knowledge of the conformational properties of polypeptide
chains should lead to a complete understanding of
protein structure and function. As described earlier, great
progress has been made toward this goal, but much remains
to be done.