Synergetic effects of pressure and chemical denaturant on protein unfolding: stability of a serine-type carboxyl protease, kumamolisin.
Kumamolisin, a serine carboxyl proteinase, is very stable and hardly denatured by single perturbation of a chemical denaturant (urea), pressure (<500 MPa) or temperature (<65 degrees C). In order to investigate the cooperative effects of these three denaturing agents, DSC, CD, intrinsic fluorescence, and fourth derivative UV absorbance were measured under various conditions. By application of pressure to kumamolisin in 8 M urea solution, substantial red-shift in the center of fluorescence emission spectral mass was observed, and the corresponding blue-shift was observed for two major peaks in fourth derivative UV absorbance, under the similar urea-containing conditions. The denaturation curves were analyzed on the basis of a simple two-state model in order to obtain thermodynamic parameters (DeltaV, DeltaG, and m values), and the combined effects of denaturing agents are discussed, with the special interest in the large cavity and neighboring Trp residue in kumamolisin.
Department of Polymer Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo, 606-8585, Japan.
Yasunori
Y
Fujimoto
Hidekazu
H
Ikeuchi
Tomoko
T
Tada
Hiroshi
H
Oyama
Kohei
K
Oda
Shigeru
S
Kunugi
D016282:Aspartic Acid Endopeptidases / Q000737:chemistry / Q000187:drug effects* / Q000528:radiation effects*; D002152:Calorimetry, Differential Scanning; D002268:Carboxypeptidases / Q000737:chemistry; D002942:Circular Dichroism; D005453:Fluorescence; D006358:Hot Temperature; D008958:Models, Molecular; D011312:Pressure; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D012996:Solutions / Q000737:chemistry; D013816:Thermodynamics; D014466:Ultraviolet Rays; D014508:Urea / Q000737:chemistry
D012996:Solutions; D014508:Urea; D002268:Carboxypeptidases; C479198:sedolisin; D016282:Aspartic Acid Endopeptidases; C078894:kumamolysin