Cold-adapted enzymes.
By far the largest proportion of the Earth's biosphere is comprised of organisms that thrive in cold environments (psychrophiles). Their ability to proliferate in the cold is predicated on a capacity to synthesize cold-adapted enzymes. These enzymes have evolved a range of structural features that confer a high level of flexibility compared to thermostable homologs. High flexibility, particularly around the active site, is translated into low-activation enthalpy, low-substrate affinity, and high specific activity at low temperatures. High flexibility is also accompanied by a trade-off in stability, resulting in heat lability and, in the few cases studied, cold lability. This review addresses the structure, function, and stability of cold-adapted enzymes, highlighting the challenges for immediate and future consideration. Because of the unique properties of cold-adapted enzymes, they are not only an important focus in extremophile biology, but also represent a valuable model for fundamental research into protein folding and catalysis.
Siddiqui
Khawar Sohail
KS
School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia. k.siddiqui@unsw.edu.au
Cavicchioli
Ricardo
R
D000220:Adaptation, Biological; D000818:Animals; D003080:Cold Temperature; D004795:Enzyme Stability; D004798:Enzymes / Q000737:chemistry / Q000378:metabolism*; D008433:Mathematics; D011487:Protein Conformation; D017510:Protein Folding; D055672:Static Electricity; D013329:Structure-Activity Relationship; D013499:Surface Properties; D013816:Thermodynamics
D004798:Enzymes