[Hydrogen exchange and proteolytic degradation of ribonuclease A. Similarities and distinctions of the kinetic mechanisms].
The studies by IR spectroscopy of the temperature dependence of the H-D exchange rate of the RNase A peptide NH atoms permit one to characterize two types of conformation fluctuations, local and global. A comparison with the temperature dependence of the proteolytic degradation rate of RNase A shows that similar in nature fluctuations allow for the H-D exchange of NH atoms and the splitting of peptide bonds of the native protein. In the low temperature region, both processes occur through local fluctuations, by way of the EX2 mechanism, and in the high temperature region, they occur through global fluctuations with the overall denaturation desorganization of the native structure, by way of the EX1 mechanism. The biphasic dependence of the rate of H-D exchange and proteolytic degradation of RNase A on urea concentration is also explained by the combination of local and global fluctuations.
Abaturov
L V
LV
Nosova
N G
NG
D000818:Animals; D006859:Hydrogen / Q000737:chemistry*; D006868:Hydrolysis; D007700:Kinetics; D008956:Models, Chemical; D010447:Peptide Hydrolases / Q000737:chemistry*; D011487:Protein Conformation; D012259:Ribonuclease, Pancreatic / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013696:Temperature; D014508:Urea / Q000737:chemistry
D006859:Hydrogen; D014508:Urea; D012259:Ribonuclease, Pancreatic; D010447:Peptide Hydrolases