Figure 3
From: New statistical potential for quality assessment of protein models and a survey of energy functions
Definition of residue orientation used to derive potentials. (A) interaction i → j is considered "parallel" if the scalar product of Cα-Cβ vectors for residues i (vector a) and j (vector b) is positive; (B) interaction i → j is considered "antiparallel i facing j" if scalar product of a and b is non-positive and scalar product of vector a and vector from Cα atom of residue i to Cα atom of residue j (vector c) is positive; (C) interaction i → j is considered as "antiparallel i pointing away from j" if both a·b and a·c scalar products are non-positive.