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Highlights in Chemical Science

News from across RSC Publishing.

Building biocatalysts with molecular Lego

27 February 2006

A better biocatalyst for the hydroxylation of phenols has been generated thanks to a protein engineering strategy known as molecular Lego. 

Gianfranco Gilardi from Imperial College London, UK, and colleagues have constructed a protein with improved electrochemical and catalytic properties by joining two enzymes. Immobilising enzymes on an electrode surface has great potential for biotechnological applications, but ensuring a steady supply of electrons to the active enzyme can be tricky, says Gilardi. 

Molecular lego
One way of doing this is to fuse the enzyme to a redox enzyme that can transfer electrons. Gilardi and colleagues assembled the BM3 haem domain from a cytochrome P450 enzyme and a redox enzyme, flavodoxin, to generate a so-called fusion protein. 

The new protein was tested by immobilising it on an electrode, with p-nitrophenol as a test substrate. The fusion protein generated the product p-nitrocatechol six times more quickly than the active enzyme alone. This could be because the redox partner controls the electron flow, says Gilardi, ensuring that electrons are directed towards the active site of the protein and are not wasted. 

The demonstration that this approach can work 'is key for its extension to more complex eukaryotic enzymes,' said Gilardi. This could lead to the construction of bioelectrodes with applications to biosensors and bioreactors. 

David Barden 


A Fantuzzi, Y T Meharenna, P B Briscoe, C Sassone, B Borgia and G Gilardi, Chem. Commun., 2006 (DOI: 10.1039/b517472d)