title: Optimization to low temperature activity in psychrophilic enzymes.
abstract: Psychrophiles, i.e., organisms thriving permanently at near-zero temperatures, synthesize cold-active enzymes to sustain their cell cycle. These enzymes are already used in many biotechnological applications requiring high activity at mild temperatures or fast heat-inactivation rate. 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. Considering the subtle structural adjustments required for low temperature activity, directed evolution appears to be the most suitable methodology to engineer cold activity in biological catalysts.
authors.affiliation: Laboratory of Biochemistry, Centre for Protein Engineering, University of Liège, Institute of Chemistry B6a, B-4000 Liège-Sart Tilman, Belgium.
authors.forename: Caroline
authors.initials: C
authors.lastname: Struvay
authors.affiliation: Laboratory of Biochemistry, Centre for Protein Engineering, University of Liège, Institute of Chemistry B6a, B-4000 Liège-Sart Tilman, Belgium.
authors.forename: Georges
authors.identifier: 0000-0001-8660-0944
authors.initials: G
authors.lastname: Feller
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D001419:Bacteria / Q000166:cytology / Q000201:enzymology*; D002384:Catalysis; D020134:Catalytic Domain / Q000502:physiology*; D003080:Cold Temperature; D004789:Enzyme Activation / Q000502:physiology*; D004795:Enzyme Stability; D011487:Protein Conformation
keywords: biotechnology; cold adaptation; enzyme activity; extremophiles; psychrophiles