Edgewise loops

Figure 2 Schematic and representative structures of different loops in G-quadruplexes (a) edgewise loop, (b) diagonal loop, (c) double-chain-reversal loop, and (d) V-shaped loop...

Figure 3 Structure of the d(GGGTTCAGG) quadruplex with triad-containing edgewise loops (a) Ribbon and (b) schematic view of the structure, (c) Alignment of G (C-A) triad. Loops are colored red anti and syn guanines are colored cyan and magenta, respectively...

The four-repeat Tetrahymena telomeric d(T2G4)4 sequence was shown to form an intramolecular G-quadruplex (Figure 11a) with one double-chain-reversal and two edgewise loops. This is the first observation of a double-chain-reversal loop sequence T2 bridges three G-tetrad layers. Furthermore this... 

The four-repeat human telomeric d[AGGG(TTAGGG)3] sequence was shown to form an intramolecular G-quadruplex in Na solution, in which guanines around each tetrad are syn syn anti anti, loops are successively edgewise-diagonal-edgewise and each G-tract has both a parallel and an antiparallel adjacent strands [Figure lO(a-c)]. By contrast, the crystal structure of the same... 

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