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Scientifica
Volume 2013 (2013), Article ID 512840, 28 pages
http://dx.doi.org/10.1155/2013/512840
Review Article

Psychrophilic Enzymes: From Folding to Function and Biotechnology

Laboratory of Biochemistry, Centre for Protein Engineering, Institute of Chemistry, University of Liège, B6a, 4000 Liège, Belgium

Received 18 October 2012; Accepted 6 November 2012

Academic Editors: S. Bottomley and A. P. Malykhina

Copyright © 2013 Georges Feller. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Psychrophiles thriving permanently at near-zero temperatures synthesize cold-active enzymes to sustain their cell cycle. Genome sequences, proteomic, and transcriptomic studies suggest various adaptive features to maintain adequate translation and proper protein folding under cold conditions. Most psychrophilic enzymes optimize a high activity at low temperature at the expense of substrate affinity, therefore reducing the free energy barrier of the transition state. Furthermore, a weak temperature dependence of activity ensures moderate reduction of the catalytic activity in the cold. In these naturally evolved enzymes, the optimization to low temperature activity is reached via destabilization of the structures bearing the active site or by destabilization of the whole molecule. This involves a reduction in the number and strength of all types of weak interactions or the disappearance of stability factors, resulting in improved dynamics of active site residues in the cold. These enzymes are already used in many biotechnological applications requiring high activity at mild temperatures or fast heat-inactivation rate. Several open questions in the field are also highlighted.