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A series of DNA aptamers bearing triazole internucleotide linkages that bind to thrombin was synthesized. The novel aptamers are structurally analogous to the well-known thrombin-inhibiting G-quadruplexes TBA15 and TBA31. The secondary structure stability, binding affinity for thrombin and anticoagulant effects of the triazole-modified aptamers were(More)
The parallel (recombination) 'R-triplex' can accommodate any nucleotide sequence with the two identical DNA strands in parallel orientation. We have studied oligonucleotides able to fold back into such a recombination-like structure. We show that the fluorescent base analogs 2-aminopurine (2AP) and 6-methylisoxanthopterin (6MI) can be used as structural(More)
Novel indolocarbazole derivative 12-(alpha-L-arabinopyranosyl)indolo[2,3-alpha]pyrrolo[3,4-c]carbazole-5,7-dione (AIC) demonstrated high potency (at submicromolar concentrations) against the NCI panel of human tumor cell lines and transplanted tumors in vivo. In search of tentative targets for AIC, we found that the drug formed high affinity intercalative(More)
Cationic porphyrin-based compounds capable of interacting with DNA are currently under extensive investigation as prospective anticancer and anti-infective drugs. One of the approaches to enhancing the DNA-binding affinity of these ligands is chemical modification of functional groups of the porphyrin macrocycle. We analyzed the interaction with DNA of(More)
Linear heteroareneanthracenediones have been shown to interfere with DNA functions, thereby causing death of human tumor cells and their drug resistant counterparts. Here we report the interaction of our novel antiproliferative agent 4,11-bis[(2-{[acetimido]amino}ethyl)amino]anthra[2,3-b]thiophene-5,10-dione with telomeric DNA structures studied by(More)
The ability of oligonucleotides 3'-d(GT)5pO(CH2)6Opd(GT)5-5' (anti[d(GT)]) and 3'-d(GT)5pO(CH2)6Opd(GT)5-3' (par[par[d(GT)]) to form tertiary structures has been studied. Circular dichroism (CD) as well as the fluorescence of the ethidium bromide (EtBr) complexes with oligonucleotides and hydrodynamic volume measurements in solutions containing 0.01 M(More)
Thermal denaturation of four oligonucleotides, viz. 3'-d(AT)5pO(CH2)6Opd(AT)5-3'(par(AT], 3'-d(AT)5pO(CH2)6Opd(AT)5-5'(anti(AT],3'-d(A)10pO(CH2) 6Op(T)10-3'(par(A-T], and 3'-d(A)10pO(CH2)6Opd(T)10-5' (anti(A-T], was studied in 0.01 M phosphate buffer, pH 7, in the presence of 0.1, 0.25, 0.5 and 1.0 M NaCl. All the oligomers were found to exist at a lower(More)
The modes of binding of 5'-[4-(aminoiminomethyl)phenyl]-[2,2'-Bifuran]-5-carboximidamide (DB832) to multi-stranded DNAs: human telomere quadruplex, monomolecular R-triplex, pyr/pur/pyr triplex consisting of 12 T*(T x A) triplets, and DNA double helical hairpin were studied. The optical adsorption of the ligand was used for monitoring the binding and for(More)
Porphyrins are a chemical class that is widely used in drug design. Cationic porphyrins may bind to DNA guanine quadruplexes. We report the parameters of the binding of 5,10,15,20-tetrakis(N-carboxymethyl-4-pyridinium) porphyrin (P1) and 5,10,15,20-tetrakis(N-etoxycarbonylmethyl-4-pyridinium) porphyrin (P2) to antiparallel telomeric G-quadruplex formed by(More)
Parallel-stranded (ps) DNAs with mixed AT/GC content comprising G.C pairs in a varying sequence context have been investigated. Oligonucleotides were devised consisting of two 10-nt strands complementary either in a parallel or in an antiparallel orientation and joined via nonnucleotide linkers so as to form 10-bp ps or aps hairpins. A predominance of(More)