Posted on 20 August 2018
Artificial metalloenzymes combine a reactive synthetic metal catalyst with a highly selective and biocompatible protein scaffold. In this way, they can combine the beneficial features of both – performing synthetic reactions with new levels of selectivity. In their latest research, the research team of Professor Anne Duhme-Klair and Professor Keith Wilson has developed a new reversible approach to combining these components.
Inspired by the way bacteria use compounds called siderophores to uptake essential iron, the team decided to employ them as linking units for their artificial enzymes. In the presence of iron(III) the siderophore strongly connects the catalyst to a protein scaffold, creating an artificial enzyme, but on reduction to iron(II), dissociation takes place and the artificial enzyme disassembles.
They used their innovative reversible anchor system to connect a synthetic iridium-containing catalyst to the protein scaffold CeuE. Normally, their iridium containing catalyst would reduce imines non-selectively to produce a racemic product. However, once bound to CeuE, the metal catalyst becomes more selective and generates an excess of one enantiomeric product. In this way, the two units linked together cooperate to make a better catalyst – an artificial metalloenzyme.
Talking about the research, Professor Duhme-Klair said: ‘Most importantly, the new reversible iron-siderophore anchor allows the metalloenzyme to function, whilst also allowing high value components, in particular the protein, to be reclaimed and reused. Hence, the replacement of catalysts that have lost activity, for example due to poisoning or decomposition, becomes possible. This has the potential to significantly extend the range of applications in which artificial metalloenzymes can be used.’
This research is published in Nature Catalysis. Read the full paper.