Intercalation binding definition

Table V. Definition of Binding Sites for Intercalation and Intercalative Covalent Binding3...

Charge-transfer constants [313] and k [314, 315] were derived from association constants of different analogs with tetracyanoethylene and 1,3,5-trinitrobenzene, respectively. Although charge-transfer interactions are supposed to be important for the interaction of some drugs with their binding sites e.g. in DNA intercalation) [116], they have not attracted much attention in QSAR studies. Values are known for only few substituents but they are definitely interrelated with other electronic parameters. 

Figure 2 (A) ICD of a DNA intercalator calculated as a function of the transition moment in the plane of the intercalation pocket and centred on the helix axis, y is the angle between the transition moment and the DNA dyad axis. Reproduced with permission from Lyng, Hard and Norden (1987) Biopolymer 2Q 1327. (B) definition of geometrical parameters of a DNA-ligand system with r=0,a = 90° and p = 0°, then y corresponds to the orientation of an intercalator transition moment (see top figure). Typical minor groove binding geometry parameters are r= 7 A, a = 45°, = 0° and y = 0.

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