Table 1.

Contributing factors to G‐quadruplex stability and their typical impact.

Parameter	Impact on structure and stability
loop length	with longer loops decrease in stability for parallel quadruplexes but also growing preference for the formation of non‐parallel topologies
loop composition	destabilizing effect of adenosine in 1‐nt loops or in the 5‘‐position of short loops when compared to T and C residues
loop length distribution	two 1‐nt loops but also a 1‐nt central loop favor parallel topologies
cation	sodium ions confer less stability than potassium ions and promote formation of non‐parallel topologies
molecular crowding	enhanced stability and a tendency of promoting transition into a parallel topology