  Proteins are the common constituents of all living cells. They are molecular
machines that interact with each other as well as with other cell products and
carry out a dizzying array of functions with distinction. These interactions
follow from their native state structures and therefore understanding
sequence-structure relationships is of fundamental importance. What is quite
remarkable about proteins is that their understanding necessarily straddles
several disciplines. The importance of geometry in defining protein native
state structure, the constraints placed on protein behavior by mathematics and
physics, the need for proteins to obey the laws of quantum chemistry, and the
rich role of evolution and biology all come together in defining protein
science. Here we review ideas from the literature and present an
interdisciplinary framework that aims to marry ideas from Plato and Darwin and
demonstrates an astonishing consilience between disciplines in describing
proteins. We discuss the consequences of this framework on protein behavior.
