  Recently, we presented a framework for understanding protein structure based
on the idea that simple constructs of holding hands or touching of objects can
be used to rationalize the common characteristics of globular proteins. We
developed a consistent approach for understanding the formation of the two key
common building blocks of helices and sheets as well as the compatible assembly
of secondary structures into the tertiary structure through the notion of
poking pairwise interactions. Here we benchmark our predictions with a detailed
analysis of structural data of over 4000 proteins from the Protein Data Bank.
We also present the results of detailed computer simulations of a simplified
model demonstrating a pre-sculpted free energy landscape, determined by
geometry and symmetry, comprising numerous minima corresponding to putative
native state structures. We explore the consequences of our model. Our results
suggest that symmetry and geometry are a powerful guide to capture the
simplicity underlying protein complexity.
