Spin-labelled nucleic acids

The spin label method developed by McConnell 15 years ago is now widely used in studies of the structure and dynamic properties of a variety of the biological systems such as proteins and protein complexes, lipids and membranes, nucleic acids, nucleoproteins, etc. The ESR spectrum of the nitroxide radcal – the spin label – is very sensitive to its microenvironment and permits easy registration of even subtle alterations in it. If spin labels are attached to different sites of a macromolecule the information can be gained about conformational properties of all these local regions and, as a result, about the dynamic behaviour of the object as a whole.