A fresh look at the Ramachandran plot and the occurrence of standard structures in proteins.

The Ramachandran plot is among the most central concepts in structural biology, seen in publications and textbooks alike. However, with the increasing numbers of known protein-structures and greater accuracy of ultra-high resolution protein structures, we are still learning more about the basic principles of protein structure. Here we use high fidelity conformational information to explore novel ways, such a geo-style and wrapped Ramachandran plots, to convey some of the basic aspects of the Ramachandran plot and of protein conformation. We point out the pressing need for a standard nomenclature for peptide conformation and propose such a nomenclature. Finally, we summarize some recent conceptual advances related to the building blocks of protein structure. The results for linear groups imply the need for substantive revisions in how the basics of protein structure are handled.