Beyond Linus Pauling: the conformation dependence of ideal peptide geometry and why it matters.

Since the early work of Pauling and Corey, the paradigm for thinking about and modeling protein backbone geometry has been that of a single ideal set of bond lengths and angles for the peptide unit. Based on the crystallographically determined structures of proteins, I published work in the mid-90s showing that there is strong evidence for systematic variations in bond angles as a function of the conformational differences only involving rotations around single bonds. We are now surveying protein structures determined at <1 � resolution to better characterize the systematic variations.