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Comparison of the bis‐intercalating complexes formed between either ditercalinium or a flexible analogue and d(CpGpCpG) 2 or d(TpTpCpGpCpGpApA) 2 minihelices: 1 H‐ and 31 P‐nmr analyses
Author(s) -
Pothier Joël,
Delepierre Muriel,
Barsi MarieChristine,
GarbayJaureguiberry Christiane,
Igolen Jean,
Le Bret Marc,
Roques Bernard P.
Publication year - 1991
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360311109
Subject(s) - chemistry , homonuclear molecule , dimer , heteronuclear molecule , crystallography , stereochemistry , intercalation (chemistry) , nuclear magnetic resonance spectroscopy , carbazole , nuclear overhauser effect , piperidine , spectroscopy , photochemistry , molecule , organic chemistry , inorganic chemistry , physics , quantum mechanics
The 400‐MHz 1 H‐ and 162‐MHz 31 F‐nmr have been used to study complexes constituted by (a) the d(TpTpCpGpCpGpApA) 2 or the d(CpGpCpG) 2 self‐complementary oligonucleotides and (b) two bifunctional 7H‐pyrido [4, 3‐c] carbazole dimer drugs, the antitumoral ditercalinium (NSC 366241), a dimer with a rigid bis‐piperidine linking chain and its pharmacologically inactive analogue, a dimer with a flexible spermine‐like linking chain. Nearly all proton and phosphorus signals have been assigned by two‐dimensional (2D) nmr (correlated spectroscopy, homonuclear Hartmann‐Hahn, nuclear Overhauser enhancement spectroscopy, 2D 31 P { 1 H} heteronuclear correlated spectroscopy and 31 P‐ 31 P chemical exchange experiments). Both drugs bis‐intercalate into the two CpG sites. The complexes show small differences in the position of the 7H‐pyrido[4, 3‐c]carbazole ring into the intercalation site and possibly in the ribose‐phosphate backbone deformation. However, the inactive analogue exhibits a longer residence lifetime in octanucleotide than the ditercalinium does. All these results are discussed in terms of differences in dimer activities.