By immobilising a protein in a biomimetic membrane on an electrode it is possible to analyse its structure and activity, reports a team from Germany.

Peter Hildebrandt and his co-workers attached cytochrome c oxidase to a modified silver electrode and then built a lipid environment around the protein. The resulting protein-tethered lipid bilayer was examined by surface enhanced resonance Raman (SERR) spectroscopy to study the haem groups at the protein's active site. The group discovered that the haem's structure is unchanged after immobilisation on the electrode and suggests that the entire enzyme structure is preserved. The enzyme also retains its activity; it can be reduced and re-oxidised by efficient electron exchange with the electrode.

Hildebrandt concludes that this immobilisation method is also applicable to other proteins and provides a method for analysing the proteins under biomimetic conditions. It therefore 'may constitute a promising concept for studying interfacial biological processes, thereby complementing other powerful techniques,' he says.

Caroline Evans