---

---

---

---

Science RSS News Feeds

---

---

Email a Friend Printer Friendly

Impersonating nature

February 08, 2000

Embargoed until 19:00 9 February 2000


Scientists at the University of Cambridge have made a breakthrough in test tube technology in the development laboratory-designed enzymes.
Using nature's tricks of mutation and selection combined with naturally occurring design features of proteins, the team, based in the Medical Research Council's Centre for Protein Engineering, have managed to achieve what takes aeons in nature.
Professor Alan Fersht, leading the team, said the experiments demonstrated how enzymes can evolve in such large numbers and bring closer the more general use of man-made enzymes.
These could then be used to make new chemicals for pharmaceutical and biotech industries.
Professor Fersht, explained:
"Enzymes are the molecules in cells which speed up all those chemical reactions which are necessary for life.
"They function under the most mild of conditions, in water at body temperature, and catalyse with exquisite precision the most difficult of reactions.
Professor Fersht explained that enzymes function by binding to a target molecule and then carrying out the chemical conversion.
Each reaction requires its own special enzyme and this is why enzymes vary so much in size and shape.
He said:
"Chemists would dearly love to harness these biological machines to make drugs and materials that currently can either be very expensive, difficult, or impossible to make using conventional chemistry.
Professor Fersht said that natural and slightly chemically modified enzymes were already in widespread use in industry - but new enzymes were needed to catalyse reactions that are not found in nature.
Dr Greg Winter and he were the first to produce a novel enzyme by protein engineering, back in 1982. But, since then, protein engineers have only been able to tinker with enzyme structure. The new work shows how large and radical changes can be made to make a range of novel enzymes as active as those found in nature.
He explained the difficulties scientists had encountered trying to evolve enzyme activity in the test tube:
"We all have the chemical and biological tools necessary to make new proteins, but we do not know the rules that lead to a protein adopting the right structure.
"We are also unable to compute the disposition of amino acids necessary for a protein to become an enzyme.
"Because of this, the goal of designing new enzymes has been an elusive task. It is the holy grail of protein engineering to design novel enzymes."
"The procedure we used employs many of the tricks used by nature, such as mutation, recombination and selection.
"But our strategy is really two-part: we also use a "rational step", which is the choice of an appropriate protein which we thought had the potential to bind to the right target molecule.
"We then transplanted the loops of amino acids that we thought necessary to catalyse the desired reaction."

Cambridge, University of