Intercalative model

Fig. 16 Schematic representation of the intercalative and minor groove directed components of a protoberberine molecule as invoked by the mixed mode DNA binding model proposed by Pilch et al. [167]. Reprinted from [167] with permission from the American Chemical Society...

For BP metabolites and metabolite model compounds UV absorption experiments provide an independent means by which binding constants for hydrocarbon intercalation into DNA can be measured. Intercalative binding gives rise to a red shift ( 10 nm) in the hydrocarbon UV absorption spectrum of PAH. Figure 7 shows absorption spectra of trans-7,8-dihydroxy-7,8-dihydro-BP at varying... 

Table IV also contains results of UV absorption studies of hydroxylation effects on the DNA intercalative binding of ben-zo[a]pyrene metabolites and metabolite model compounds. The most important feature of these results is that hydrolysis of BPDE to BPT causes a four-fold reduction in the intercalation association constant. Of all the BP derivatives studied, the tetrol has the lowest binding constant for intercalation. The small binding constant of the tetrol compared with BPDE, coupled with the DNA catalyzed hydrolysis of BPDE to the tetrol may provide a detoxification pathway for removal of a portion of unreacted intercalated BPDE.

A theoretical analysis is presented for the binding of the four dia-stereoisomers of benzo[a]pyrene diol epoxides (BPDEs) to N2(g), N6(a), 06(G) and NU(c). Molecular models for binding and stereoselectivity involving intercalation, intercalative covalently and externally bound forms are presented. Molecular mechanics calculations provide the energetics which suggest possible structures for the formation of each of the principal DNA-BPDE complexes. Stereographic projections are used to illustrate the molecular structures and steric fits. The results of previous calculations on intercalation and adduct formation of BPDE l(+) in kinked DNA (37) are summarized and extended to include the four diastereoisomers l( ) and II( ). The theoretical model is consistent with the observed experimental data. 

We chose to show the application of techniques employed to study supramolecular dynamics to host systems that have defined binding sites and, therefore, form host-guest complexes with defined stoichiometries. CDs were chosen because they represent a host with only one binding site, and therefore can be viewed as a model system for hosts with the lowest degree of complexity. DNA was chosen because it provides multiple binding sites for small molecules, i.e. intercalative and groove binding, while the DNA is structurally fairly well defined. 

Influence of Acid Additives on Retention Characteristics of 2-Methoxy-2-(1-Naphthyl)Propionic Acid on a 0-9-(tert-ButylcarbamoyOQuinine CSP as Assessed by the Characteristic Parameters of the Stoichiometric Displacement Model (Slopes and Interc ... 

Henrici-Olive, G. and Olive, S. Molecular Intercations and Macroscopic Properties of Polyacrylonitrile and Model Substances. Vol. 32, pp. 123-152. 

Fig. 1 Continental source attribution of the ozone observed on each day of 2008 at the EMEP rural monitoring station GB0049R at Weyboume on the North Norfolk coast of eastern England using ozone labelling techniques in a global and a regional photochemical model. Key regional refers to the ozone advected directly over the local- and regional-scales to the location North America to that formed over that continent and over the North Atlantic and east Pacific Asia to that formed over that continent and over the western Pacific Europe-interc to that advected intercontinentally around latitude circles and back into Europe Tropical to that from the southern hemisphere and tropics...

Two-dimensional NMR has also been used to investigate the binding of the two enantiomers of the complex [Ru(phen)3]2+ (phen = 1,10-phenanthroline) to DNA using a decanucleotide as model and demonstrates that both enantiomers bind in the minor groove, rather than intercalatively (Eriksson et al., 1992). 

These observations are consistent with an intercalative mode of binding in the interaction of tilorone hydrochloride with double-helical DNA. These results were not examined in an attempt to verify whether they agree with measurements of the length increase on sonicated DNA. For this reason, the intercalation model of the DNA complex remains tentative. 

Figure 6.1 Structural model for the Intercalated polypyrrole chains within the van der Waals gap of FeOCI. (Reprinted with permission from Solid State Ionics, In situ intercalative polymerization chemistry of FeOCI. Generation and properties of novel, highly conductive Inorganic/organic polymer microlaminates by M. G. Kanatzidis, H. O. Marcy, W. J. McCarthy et al., 594-608, 1-3. Copyright (1989) Elsevier Ltd)...

As a detailed feature of the intercalative complex, the following two models have been proposed ... 

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