Echinomycin: a bifunctional intercalating antibiotic

Waring, Michael J.; Wakelin, L. P. G.

doi:10.1038/252653a0

Cited by 280 publications

(216 citation statements)

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“…(Table 1) The target compounds (5a-e) (Table 2) designated as 2-aryl -s= triazino [1], [3], [5] -thiazolo [6], [5 -b] quinoxalin-4-thiones were prepared by refluxing a mixture of 4 with thiocyanate in dioxane solvent. All the synthesized compounds have been characterized by IR, 1 H NMR, [13]C NMR mass and element analysis. The spectral and analytical data of new compounds (4a-e and 5a-e) are presented in experimental section.…”

Section: Resultsmentioning

confidence: 99%

“…In addition a number of quinoxalinederivatives have been shown to passes a wide variety of pharmacological properties like antibacterial [4], antifungal [5], antituberculosis [6], antitumor [7], antiviral [8] and antiflammatiroy [9]. Further s-triazines have been very well established as diuretics [10] and antiviral agents [11][12][13][14]. Several s-triazine compounds have been thoroughly examined in neoplastic diseases with promising results but despite the considerable efforts denoted to these compounds, they have not proven to have any clinical application [15], [16] …”

Section: Introductionmentioning

confidence: 99%

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Multistep organic synthesis leading to the formation of triazinothiazoloquinoxalines involving cost effective rea-gents

Yadav

Pandey

2017

Int. J. Sci. World

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Multistep organic synthesis leading to the formation of triazinothiazoloquinoxalines involving cost effective rea-gents

Yadav

Pandey

2017

Int. J. Sci. World

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“…Its high wavelength absorption band is centered at 325 nm (44), and it exhibits a weak G-C binding specificity (25), producing effects on the fluorescence of quinacrine-DNA complexes which are complementary to those of netropsin. Echinomycin increases the fluorescence of a fixed amount of quinacrine complexed to an excess of calf thymus DNA (Fig.…”

Section: Resultsmentioning

confidence: 99%

Interactions between pairs of DNA‐binding dyes: Results and implications for chromosome analysis

et al. 1980

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A number of DNA-binding dyes, with spectral properties making them suitable as components of energy donor-acceptor pairs, are described. If such pairs are used to stain metaphase chromosomes, and if the energy acceptor (e.g., actinomycin D or methyl green) has a binding specificity opposite to the binding or fluorescence specificity of the donor (e.g,, 33258 Hoechst, quinacrine or chromomycin A3), contrast in donor fluorescence can be enhanced, leading to patterns selectively highlighting standard or reverse chromosome bands or particular polymorphic regions. Such results presumably reflect chromosomal regions enriched in 10-20 base pair clusters to which the donor binds and fluoresces but to which the acceptor cannot bind. For other pairs, involving counterstains such as netropsin or echinomycin, which are not suitable as energy acceptors, specific changes observed in polymorphic region fluorescence are most likely due to binding competition between dyes. Dye pairs producing contrast by either method can be used to differentiate between homologous chromosomes or to facilitate detection of specific chromosomal rearrangements. Preliminary data indicate that contrast enhancement generated in fixed metaphase chromosomes spread on microscopic slides can also be observed in suspensions of unfixed metaphase chromosomes, reinforcing the expectation that the methodology described will be of use in flow cytometry.Key terms: Energy transfer, fluorescence, binding competition, chromosome banding patterns, polymorphisms, rearrangements, flow cytometry.Staining metaphase chromosomes simultaneously with pairs of different dyes can lead t o new fluorescence patterns. In addition to the signals produced when the dyes are used independently, information can be generated by interactions between these dyes. For example, two dyes can compete for binding to certain chromosomal sites, which can thereby be stained differentially (15,41) Alternatively, indirect effects of one dye on another can be mediated via conformational changes induced in DNA (46). In addition, because of a coincidence between the range of separations possible between ' Supported by Grant GM21121 from the National Institutes of Health. S.A.L. is the recipient of a Research Career Development Award GM00122 from the National Institute of General Medical Sciences and E.S. is supported in part by a grant from the Whitaker Foundation.* Presented in part at Automated Cytology VII, Asilomar, California, November 25-30, 1979. dye molecules bound to DNA (20) and the effective distance over which dye electronic transition dipoles can interact (typically 5 50 A) (9, 42), the transfer of electronic excitation energy from one dye to another in doubly stained chromatin can be appreciable (14,16,17,36).We have recently shown that the enhanced contrast in metaphase chromosome staining produced by certain dye pairs is due largely to energy transfer, while that produced by other pairs, which fail to satisfy spectral overlap criteria, is due primarily to binding competition (37)....

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“…They are expected to bind to DNA more tightly, and with greater selectivity, than comparable simple (monofunctional) intercalators. Echinomycin was the first bifunctional intercalator to be identified [3] and consequently its DNA-binding properties have been extensively characterised: it does indeed display considerable sequence-selectivity, which is evident in its interaction with natural DNAs as well as with synthetic polynucleotides [4]. The same is true of other quinoxaline antibiotics but their patterns of sequenceselectivity differ radically from that seen with echinomycin, especially as regards their binding to poly(dA-dT) and poly(dG-dC) [5][6][7].…”

Section: Introductionmentioning

confidence: 99%