Protein structure & enzyme function

Electron spin resonanace of iron-sulphur enzymes

"EPR spectroscopy is reasonably sensitive for bio-chemical purposes, typically requiring concentrations of paramagnetic species in the  10-100 µM range."

 

Analysis of multi-enzyme systems that are otherwise difficult to distinguish can be done easily since each chemical configuration gives a significant EPR signal. The highly sensitive measuremnt saves a lot of work on purification. Instead, intact organelles as well as other cellular systems can be observed directly.

 

Structural insights

EPR proves to be a highly sensitive tool for biostructural observations. Here are three reasons why:

  • distorted EPR-spectra due to centre-centre interactions over 1.2 nm

  • ΔMg = 2 transition is detectable

  • slight changes of confirmation result in variation of EPR reflex shape and g-value