Enzyme Stabilization by Directed Evolution

Abstract

Engineered enzymes are widely used in industrial processes, where they provide distinct advantages over the naturally-occurring ones (1, 2). Engineering a useful enzyme is particularly difficult when the target functions—for example, the environment in which it must work or the substrates it must accept--differ significantly from the natural ones. ‘Rational ‘design approaches depend on detailed knowledge of enzyme structure and function. Unfortunately, the three-dimensional conformations of most enzymes are unknown, and, even when a structure is available, the relationship of structure to function is often not apparent. Further complicating the design problem is the fact that the effects of mutations can be propagated over long distances, such that mutations far from the active site can affect catalytic activity (3–5) and even single mutations can generate large structural changes (6, 7).