Enzymes are biological molecules which speed up specific reactions. Enzymes from most organisms lose their structural organisation and stop working at temperatures higher than about 40°C. This lack of stability poses a problem in many industrial processes in which enzymes are used, including for producing biofuels, for diagnostics, and in the food industry and so ways to increase enzyme stability are highly desirable. Chris Schoene, a PhD candidate mid-way through an Industrial CASE studentship at the University of Oxford, used a bacterial ‘glue’ called SpyTag to stick opposite ends of enzymes together and form a closed loop. This had a dramatic effect on the resilience of one enzyme, β‑lactamase, allowing it to be boiled and still retain a high level of function. Chris then tested the method on another enzyme, Dihydrofolate reductase, and found it too was able to retain function after boiling. Chris said: “Sticking the termini of proteins together with alternative technologies usually only improved the survival of the proteins by 5°C or so. With SpyTag we just kept heating it all the way to 100°C and the enzyme still didn’t die. We’re very excited by these results and hope that the SpyTag approach might enable enzymes to tolerate some really tough conditions, for example in green synthesis of pharmaceuticals or for biosensors.” Chris was working with Professor Mark Howarth, whose team created the SpyTag glue. Professor Howarth said: “Most of our work on SpyTag has been on using it to link different things together, such as for tracking receptors on cells or binding proteins to magnetic beads for sensitive capture of rare cells in blood. Chris’ discovery of this new route to resilient enzymes has opened up a whole new direction for us to explore.” The team believes that locking the enzyme with SpyTag did not prevent the enzyme from altering shape when heated, but rather allowed it to return to the correct formation when cooled back down. Only in the correct formation is an enzyme able to maintain its function. The team now plans to apply this technology to other industrially important enzymes in collaboration with Sekisui Diagnostics. The paper “SpyTag/SpyCatcher Cyclization Confers Resilience to Boiling on a Mesophilic Enzyme” is published in the journal Angewandte Chemie and is available at: http://onlinelibrary.wiley.com/doi/10.1002/anie.201402519/abstract Source: Biotechnology and Biological Sciences Research Council (BBSRC)
