Figure 2.

Schematic diagrams of the single-loop models investigated in this work: L_n, lateral narrow loop; L_w, lateral wide loop; D, diagonal loop; P₃a/P₃p, anti-parallel/parallel propeller loop spanning three quartet layers; P₂a, anti-parallel propeller loop spanning two quartet layers; P₄a/P₄p, anti-parallel/parallel propeller loop spanning four quartet layers. For each of the eight models, six different loop sequences were investigated: d0, dT, dT₂, dT₃, dTTA, and dT₄. Stems of the L_n, L_w, D, and P₃a models share the same initial structure taken from the first model of the NMR structure 2GKU.(56)