Spin label

Spin labels are normally used as tools for probing proteins or biological membrane-local dynamics using electron paramagnetic resonance spectroscopy.

Recently, spin-labelling has also been used to probe chemical local environment in NMR itself, in a technique known as Paramagnetic Relaxation Enhancement (PRE).

Recent developments in the theory and experimental measurement of PREs have enabled the detection, characterization and visualization of sparsely populated states of proteins and their complexes.

[1] Such states, which are invisible to conventional biophysical and structural techniques, play a key role in many biological processes including molecular recognition, allostery, macromolecular assembly and aggregation.

Spin labelled fatty acids have been extensively used to understand dynamic organization of lipids in bio-membranes and membrane biophysics.