Topography of nucleic acid helixes in solution. XXIX. Steric effects on the intercalation of aromatic cations to deoxyribonucleic acid

Abstract

Canthiphytine (5) from Haplophytine. To a solution of haplo-phytine (132 mg) in dilute hydrochloric acid (3 ml, 12%) was added zinc dust (250 mg), and the mixture was refluxed under nitrogen for 1 hr. The mixture was left overnight. The clear pale brown solution was cooled in an ice bath, basified with ammonia, and extracted with ether. The washed and dried ether layer was concentrated and the dark residue (60 mg) was treated with methanolic hydrogen chloride. The gummy solid was crystallized from acetone-methanol to give 7 mg of canthiphytine hydrochloride: mp 302°dec; m/e 256.1211 (M+ 256.1212); m/e 257 (14), 256(82), 255 (37), 239 (12), 214 (17), 213 (100), 201 (5), 200 (30), 199 (20). 186 (5), 185 (30), 184 (32), 183 (4), 172 (4), 171 (9), 170 (5), 166 (3). This material was identical (mixture melting point and ir spectrum in KBr) with the hydrochloride of synthetic 5. Supplementary Material Available. Elemental analyses for the indicated compounds will appear following these pages in the microfilm edition of this volume of the journal. Photocopies of the supplementary material from this paper only or microfiche (105 X 148 mm, 20X reduction, negatives) containing all of the supplementary material for the papers in this issue may be obtained from

There is a correlation between the DNA affinity and mutagenicity of several 3-amino-1-methyl-5H-pyrido[4,3-b]indoles.

“…The affinity of 3-amino-1-methyl-5H-pyrido [4,3-b]indole and its derivatives for DNA was similar to that noted previously for several other compounds (13,15,32,37,38), although the precise nature of the noncovalent interaction obtained with 1-8 is unclear. Unlike polycyclic aromatic hydrocarbons, the indole derivatives are quite water soluble, so that a solubilization effect (39) is not likely.…”

“…The bacteria were resuspended in phosphate-buffered saline and plated in triplicate in the presence and absence of 8-azaguanine. After incubation at 37°C for [36][37][38][39][40] hr, the plates were scored and the data were expressed as the mutant fraction-i.e., the average number of 8-azaguanine-resistant clones divided by the average number of 8-azaguanine-sensitive clones.…”

Synthesis, characterization and DNA binding of copper(II) complexes with mixed ligands of 1, 10-phenanthroline / 2-2’ bipyridyl, L-methionine and ethylamine: Studies on antimicrobial and anti-cancer activities

“…Since the relative specific viscosity (η/ η 0 ) (η and η 0 are the specific viscosities of DNA in the presence and absence of the complex, respectively) of DNA reflects the increase in contour length associated with separation of DNA base pairs caused by intercalation, a classical intercalator such as ethidium bromide could cause a significant increase in viscosity of DNA solutions. In contrast, a partial and/or nonclassical intercalation of the ligand could bend or kink DNA, resulting in a decrease in its effective length with a concomitant increase in its viscosity [27,28] , while the electrostatic and groove binding cause little or no effect on the relative viscosity of DNA solutions. Therefore viscosity measurements, which are sensitive to the changes in the contour length of DNA, are useful to probe for DNA intercalation by complexes.…”

Structures, spectra, and DNA-binding properties of mixed ligand copper(II) complexes of iminodiacetic acid: The novel role of diimine co-ligands on DNA conformation and hydrolytic and oxidative double strand DNA cleavage

“…6). The significant increase in viscosity of the dpq complex, which, however, is less than that for the potential intercalator viz., ethidium bromide [58], is obviously due to the partial insertion of the dpq ligand in between the DNA base pairs (cf. above) leading to increase in separation of base pairs at intercalation sites and hence an increase in overall DNA contour length [59,60,30].…”