Thermostability of refolded ovalbumin and S-ovalbumin.
Ovalbumin, a member of the serpin superfamily, is transformed into a thermostabilized form, S-ovalbumin, during storage of shell eggs or by an alkaline treatment of the isolated protein (DeltaT(m)=8 degrees C). As structural characteristics of S-ovalbumin, three serine residues (Ser164, Ser236 and Ser320) take the D-amino acid residue configuration, while the conformational change from non-thermostabilized native ovalbumin is very small. To assess the role of the structural characteristics on protein thermostabilization, ovalbumin and S-ovalbumin were denatured to eliminate the conformational modulation effects and then refolded. The denatured ovalbumin and S-ovalbumin were correctly refolded into the original non-denatured forms with the corresponding differential thermostability. There was essentially no difference in the disulfide structures of the native and refolded forms of ovalbumin and S-ovalbumin. These data are consistent with the view that the configuration inversion, which is the only chemical modification directly detected in S-ovalbumin so far, plays a central role in ovalbumin thermostabilization. The rate of refolding of S-ovalbumin was greater than that of ovalbumin, indicating the participation, at least in part, of an increased folding rate for thermodynamic stabilization.
Takahashi
Nobuyuki
N
The Division of Applied Life Sciences, The Graduate School of Agriculture, Kyoto University, Kyoto. nobi@kais.kyoto-u.ac.jp
Onda
Maki
M
Hayashi
Kaori
K
Yamasaki
Masayuki
M
Mita
Tomoyoshi
T
Hirose
Masaaki
M
D006358:Hot Temperature; D007700:Kinetics; D010047:Ovalbumin / Q000737:chemistry*; D011489:Protein Denaturation; D017510:Protein Folding; D020673:Protein Renaturation; D013997:Time Factors
C104026:S-ovalbumin; D010047:Ovalbumin