TY - JOUR
T1 - Evidence for the existence of an unfolding intermediate state for aminoacylase during denaturation in guanidine solutions
AU - Bai, Ji Hong
AU - Xu, Dong
AU - Wang, Hong Rui
AU - Zheng, Si Yang
AU - Zhou, Hai Meng
N1 - Funding Information:
The present investigation was supported in part by a grant from the Pandeng Project of the China Commission for Science and Technology and by Grant 39570180 of the China National Science Foundation.
Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1999/2/10
Y1 - 1999/2/10
N2 - The equilibrium unfolding of pig kidney aminoacylase in guanidinium chloride (GdmCl) solutions was studied by following the fluorescence and circular dichroism (CD). At low concentrations of GdmCl, less than 1.0 M, the fluorescence intensity decreased with a slight red shift of the emission maximum (from 335 to 340 nm). An unfolding intermediate was observed in low concentrations of denaturant (between 1.2 and 1.6 M GdmCl). This intermediate was characterized by a decreased fluorescence emission intensity, a red-shifted emission maximum, and increased binding of the fluorescence probe 1-anilino-8-naphthalenesulfonate. No significant changes of the secondary structure were indicated by CD measurement. This conformation state is similar to a molten globule state which may exist in the pathway of protein folding. Further changes in the fluorescence properties occurred at higher concentrations of GdmCl, more than 1.6 M, with a decrease in emission intensity and a significant red shift of the emission maximum from 340 to 354 nm. In this stage, the secondary structure was completely broken. A study of apo-enzyme (Zn2+-free enzyme) produced similar results. However, comparison of the changes of the fluorescence emission spectra of native (Holo-) enzyme with Zn2+-free (Apo-) enzyme at low GdmCl concentrations showed that the structure of the Holo-enzyme was more stable than that of the Apo-enzyme. Copyright (C) 1999 Elsevier Science B.V.
AB - The equilibrium unfolding of pig kidney aminoacylase in guanidinium chloride (GdmCl) solutions was studied by following the fluorescence and circular dichroism (CD). At low concentrations of GdmCl, less than 1.0 M, the fluorescence intensity decreased with a slight red shift of the emission maximum (from 335 to 340 nm). An unfolding intermediate was observed in low concentrations of denaturant (between 1.2 and 1.6 M GdmCl). This intermediate was characterized by a decreased fluorescence emission intensity, a red-shifted emission maximum, and increased binding of the fluorescence probe 1-anilino-8-naphthalenesulfonate. No significant changes of the secondary structure were indicated by CD measurement. This conformation state is similar to a molten globule state which may exist in the pathway of protein folding. Further changes in the fluorescence properties occurred at higher concentrations of GdmCl, more than 1.6 M, with a decrease in emission intensity and a significant red shift of the emission maximum from 340 to 354 nm. In this stage, the secondary structure was completely broken. A study of apo-enzyme (Zn2+-free enzyme) produced similar results. However, comparison of the changes of the fluorescence emission spectra of native (Holo-) enzyme with Zn2+-free (Apo-) enzyme at low GdmCl concentrations showed that the structure of the Holo-enzyme was more stable than that of the Apo-enzyme. Copyright (C) 1999 Elsevier Science B.V.
UR - http://www.scopus.com/inward/record.url?scp=0033039247&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033039247&partnerID=8YFLogxK
U2 - 10.1016/S0167-4838(98)00282-9
DO - 10.1016/S0167-4838(98)00282-9
M3 - Article
C2 - 10082931
AN - SCOPUS:0033039247
SN - 0167-4838
VL - 1430
SP - 39
EP - 45
JO - Biochimica et Biophysica Acta - Protein Structure and Molecular Enzymology
JF - Biochimica et Biophysica Acta - Protein Structure and Molecular Enzymology
IS - 1
ER -