A study of the self-assembly of 2'-deoxyguanosine 3':5'-cyclic monophosphate, d(cGp), by CD and X-ray diffraction

2'-Deoxyguanosine 3':5'-cyclic monophosphate forms in water cholesteric and hexagonal columnar mesophases. The polymorphic behaviour and the structural building blocks of the liquid crystalline phases, as determined by optical microscopy, CD spectroscopy and X-ray diffraction, are comparable to those found with all the deoxyguanylates investigated so far (in particular with deoxuguanosine 5'- and 3'-monophosphate). The present results show that the formation of a stacked array of planar G-tetramers, a necessary condition for the existence of the columnar mesophases, occurs even in the absence of hydrogen bonding groups linking the molecules along the length of the columns.