Figure 1.

Glycine dipeptide oligomers (in the parallel $\beta$-sheet conformation) used to calculate the interaction energy, many-body interaction energy, and the nonadditive and additive contributions to the many-body interaction of the ${\text{Gly}}_2{\text{:Gly}}_2$ oligomer. For each oligomer, the interaction energies between glycine dipeptides above and below the dashed line are calculated using eq 21. (A) ${\text{Gly}}_2{\text{:Gly}}_2$, (B) ${\text{Gly}}_2\text{:XGly}$, (C) ${\text{GlyX:Gly}}_2$, and (D) $\text{GlyX:XGly}$. Refer to the Theory section for detailed descriptions.