Spin label is an organic molecule that has an unpaired electron and the ability to bind to other molecules.
An unpaired electron makes it possible to observe the spectra of electron paramagnetic resonance (EPR) , thereby the spin label serves as a probe for EPR . The EPR spectra of spin labels carry information on local dynamics (for example, in biological membranes, proteins ), the polarity and pH of the environment, and also serve to measure distances (up to 8 nm) in large molecules.
The most common spin labels are derivatives of nitroxyl radicals .
Literature
- Lichtenstein G.I. Spin tag method in molecular biology. - M .: Nauka, 1974. - 256 p.