  Both symmetry and organized breaking of symmetry have a pivotal r\^ole in our
understanding of structure and pattern formation in physical systems, including
the origin of mass in the Universe and the chiral structure of biological
macromolecules. Here we report on a new symmetry breaking phenomenon that takes
place in all biologically active proteins, thus this symmetry breaking relates
to the inception of life. The unbroken symmetry determines the covalent bond
geometry of a sp3 hybridized carbon atom. It dictates the tetrahedral
architecture of atoms around the central carbon of an amino acid. Here we show
that in a biologically active protein this symmetry becomes broken. Moreover,
we show that the pattern of symmetry breaking is in a direct correspondence
with the local secondary structure of the folded protein.
