Stability of polyomavirus major capsid protein VP1 under denaturants guanidine hydrochloride and urea.
The guanidine hydrochloride (GdnHCl)- and urea-induced equilibrium denaturation of recombinant polyomavirus (Py) major capsid protein VP1 was studied by circular dichroism and fluorescence spectroscopy. Both secondary and tertiary structures of PyVP1 were shown to be disrupted in the presence of denaturants. Although the far-UV circular dichroism (CD) spectra of PyVP1 in the denaturants exhibit similar two-phase transition as those obtained from the fluorescence measurements, the unfolding of PyVP1 in GdnHCl was shown to be more complex than a similar two-state mechanism. The presence of unfolding intermediates is manifested by the noncoincidence of transitions when detected by different probes. The unfolding intermediate appeared to be stabilized by 1 M NaCl. Addition of Ca2+ and 2-mercaptoethanol does not show significant effect on the conformational stability of PyVP1. Unfolding of PyVP1 in GdnHCl was shown to be an irreversible process.
Yang
Y W
YW
School of Pharmacy, College of Medicine, National Taiwan University, Taipei, ROC.
Teng
C C
CC
D002213:Capsid / Q000737:chemistry*; D036022:Capsid Proteins; D002942:Circular Dichroism; D019791:Guanidine; D011120:Polyomavirus / Q000737:chemistry*; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013050:Spectrometry, Fluorescence; D014508:Urea
D036022:Capsid Proteins; C062481:VP1 protein, polyomavirus; D014508:Urea; D019791:Guanidine