Fig. 7.

Structural models of G-wires. a A G-tetrad is represented as a square for simplifying schematic representation of various G-wire models. b Three slipped-strand models: "(2,2) Adjacent", "(2,2) Diagonal" and "(3,1)" models. Left: top view of a G-tetrad; slipped strand indicated as a red dot. Right: side view of a G-wire fragment containing three G-tetrad blocks; G-tetrads are represented as planes. c Rotamers of the "(2,2) Diagonal" slipped-strand model: − 90°, 0° and + 90° rotation occurring at the TT thymine bulge (red). Rotation angle nomenclature is defined by the relative rotation of the top G-tetrad block with respect to the bottom G-tetrad block and the 5′ → 3′-strand directionality as indicated