Empirical Protein Energy Maps

WORK by several groups^1–5 has led to the calculation of energy maps for the peptide unit, which is the dependence of the conformational energy E_?,ψ on the torsional angles around the N-C^α bond (?) and the C^α-C bond (ψ)⁶ (Fig. 1) by using a standard set of bond lengths, valence angles and potential functions derived from small molecules. Although calculated maps are improved by refining the potential functions and increasing the number of parameters, there are differences according to the particular assumptions made. The most probable conformation of a peptide unit in proteins, using the available experimental information, is given by the following approach.