A comparison of computational calculations and a survey of high resolution structures confirm the presence of a new interaction that is globally relevant to protein structure. The results, published online this week in Nature Chemical Biology, prove that an unexpected interaction along the protein backbone, called an n→pi* interaction is fundamental to protein structure, stability and folding.
Ronald T. Raines, Derek N. Woolfson and colleagues used calculations to find the most likely candidates for significant n→pi* interactions and then analyzed a database of high resolution crystal structures. They found compelling evidence that n→pi* interactions are ever-present in proteins, particularly in basic units of secondary structure, such as alpha-helices and poly-proline helices. The importance of these local, n→pi* interactions in proteins is essential to understanding the mechanisms of protein folding and stabilizing folded protein structures.