Activity-stability relationships in extremophilic enzymes.
Psychrophilic, mesophilic, and thermophilic alpha-amylases have been studied as regards their conformational stability, heat inactivation, irreversible unfolding, activation parameters of the reaction, properties of the enzyme in complex with a transition state analog, and structural permeability. These data allowed us to propose an energy landscape for a family of extremophilic enzymes based on the folding funnel model, integrating the main differences in conformational energy, cooperativity of protein unfolding, and temperature dependence of the activity. In particular, the shape of the funnel bottom, which depicts the stability of the native state ensemble, also accounts for the thermodynamic parameters of activation that characterize these extremophilic enzymes, therefore providing a rational basis for stability-activity relationships in protein adaptation to extreme temperatures.
D'Amico
Salvino
S
Laboratory of Biochemistry, University of Liège, Institute of Chemistry B6, B-4000 Liège-Sart Tilman, Belgium.
Marx
Jean-Claude
JC
Gerday
Charles
C
Feller
Georges
G
D002152:Calorimetry, Differential Scanning; D004926:Escherichia coli / Q000235:genetics*; D006358:Hot Temperature; D011487:Protein Conformation; D011489:Protein Denaturation; D031161:Pseudoalteromonas / Q000201:enzymology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship; D000516:alpha-Amylases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D011994:Recombinant Proteins; D000516:alpha-Amylases