The Ramachandran Plot, first introduced half a century ago, maps the backbone torsion angles-ϕ and ψ-for a dipeptide, showing that steric restrictions eliminate approximately ¾ of conceivable conformational space. Titis chapter revisits and then generalizes this early result, a follow-on to ideas implicit in the Plot. Ramachandran's dramatic result notwithstanding, subsequent work seemed to indicate that dipeptide restrictions have a negligible impact on overall protein conformation. Consequently, later decades witnessed an ever-increasing emphasis on the significance of attractive forces in folding simulations, with concomitant neglect of the organizing power of excluding forces. Attractive forces act by stabilizing native interactions, while excluding forces such as steric clashes act by destabilizing non-native interactions. This chapter summarires some recent advances that pertain to both types of excluding forces: (a) systematic local steric clashes beyond the dipeptide and (b) the strongly destabilizing influence of buried polar groups that lack hydrogen bond partners.
|Original language||English (US)|
|Title of host publication||Biomolecular Forms and Functions: A Celebration of 50 Years of the Ramachandran Map|
|Publisher||World Scientific Publishing Co.|
|Number of pages||8|
|State||Published - Jan 1 2012|
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)