Slow unfolding explains high stability of thermostable ferredoxins: common mechanism governing thermostability?
The role of kinetics in governing exceptional stability of thermophilic ferredoxins has been explored. Strikingly, unfolding-rate constants (pH 7, 20 degrees C) are over eight (log(10)) orders of magnitude slower for the thermophiles than for a large set of unrelated mesophilic proteins. Also at low pH, where ionic interactions are diminished, unfolding of the thermophilic ferredoxins is significantly slower than unfolding of the mesophiles at pH 7, emphasizing the importance of hydrophobic interactions. A kinetic barrier towards unfolding may be a common strategy used by many proteins to withstand extreme conditions.
Wittung-Stafshede
Pernilla
P
Biochemistry and Cell Biology and Chemistry Departments, Rice University, 6100 Main Street, Houston, TX 77251, USA. pernilla@rice.edu
D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D005288:Ferredoxins / Q000737:chemistry* / Q000378:metabolism*; D019791:Guanidine / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D011489:Protein Denaturation / Q000187:drug effects; D017510:Protein Folding; D013696:Temperature; D013816:Thermodynamics
D001426:Bacterial Proteins; D005288:Ferredoxins; D019791:Guanidine