Physical Effects on DNA

In the absence of crystallographic data, there exist many other experimental criteria that allow the determination of the binding mode [30,38]. They can be classified into two categories the measurement of physical effects on DNA and spectroscopic studies (Table 1, first column, C and A respectively). Irrespective of the binding mode, the binding parameters (the affinity constant and the number n of occupied base pairs per molecule) can be determined from equilibrium dialysis and Scatchard plots [43 46] 

The methods giving access to the effects of interacting molecules on the physical properties of DNA are cited first because they are considered as the most classical ones for testing intercalation, although in the particular case of the metallic complexes developed below, they have bren generally less applied than the spectroscopic techniques. 

Among these methods, hydrodynamic measurements of sedimentation coefficients and viscosity are classical [43,47]. The insertion of a true intercalator (ethidium bromide for example) between the stacking of bases produces 

Methods Observations Consistent (-1-), or inconsistent (—) with intercalation Ref. 

Spectroscopy 1. Absorption, luminescence - Hypochromicity in absorption, enhanced luminescene when -1- B-DNA, -1- 48 

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