Reference : Structural and functional adaptations to extreme temperatures in psychrophilic, mesop...
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
http://hdl.handle.net/2268/15767
Structural and functional adaptations to extreme temperatures in psychrophilic, mesophilic, and thermophilic DNA ligases
English
Georlette, D. [> > > >]
Damien, B. [> > > >]
Blaise, Vinciane mailto [Université de Liège - ULg > Département des sciences et gestion de l'environnement > Département des sciences et gestion de l'environnement >]
Depiereux, E. [> > > >]
Uversky, V. N. [> > > >]
Gerday, Charles mailto [Université de Liège - ULg > Services généraux (Faculté des sciences) > Relations académiques et scientifiques (Sciences) >]
Feller, Georges mailto [Université de Liège - ULg > Département des sciences de la vie > Labo de biochimie >]
26-Sep-2003
Journal of Biological Chemistry
Amer Soc Biochemistry Molecular Biology Inc
278
39
37015-37023
Yes (verified by ORBi)
International
0021-9258
Bethesda
[en] Psychrophiles, host of permanently cold habitats, display metabolic fluxes comparable to those exhibited by mesophilic organisms at moderate temperatures. These organisms have evolved by producing, among other peculiarities, cold-active enzymes that have the properties to cope with the reduction of chemical reaction rates induced by low temperatures. The emerging picture suggests that these enzymes display a high catalytic efficiency at low temperatures through an improved flexibility of the structural components involved in the catalytic cycle, whereas other protein regions, if not implicated in catalysis, may be even more rigid than their mesophilic counterparts. In return, the increased flexibility leads to a decreased stability of psychrophilic enzymes. In order to gain further advances in the analysis of the activity/flexibility/stability concept, psychrophilic, mesophilic, and thermophilic DNA ligases have been compared by three-dimensional-modeling studies, as well as regards their activity, surface hydrophobicity, structural permeability, conformational stabilities, and irreversible thermal unfolding. These data show that the cold-adapted DNA ligase is characterized by an increased activity at low and moderate temperatures, an overall destabilization of the molecular edifice, especially at the active site, and a high conformational flexibility. The opposite trend is observed in the mesophilic and thermophilic counterparts, the latter being characterized by a reduced low temperature activity, high stability and reduced flexibility. These results strongly suggest a complex relationship between activity, flexibility and stability. In addition, they also indicate that in cold-adapted enzymes, the driving force for denaturation is a large entropy change.
http://hdl.handle.net/2268/15767

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