The compactness of ribonuclease A and reduced ribonuclease A

FEBS Letters

Fan, Ying-Xin³  Kimura, Kazumoto²  Zhou, Jun-Mei³  Kihara, Hiroshi⁴  Amemiya, Yoshiyuki¹ 

[1] Faculty of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan;Division of Medical Electronics, Dokkyo University School of Medicine, Mibu, Tochigi 321-02, Japan;National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, Beijing 100101, PR China;Physics Laboratory, Kansai Medical University, Uyamahigashi, Hirakata, Osaka 573, Japan

关键词: Ribonuclease A;    Disulfide bond;    Globularity;    Small-angle X-ray scattering;    Protein folding;   

DOI  :  10.1016/S0014-5793(98)00639-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The compactness of ribonuclease A with intact disulfide bonds and reduced ribonuclease A was investigated by synchrotron small-angle X-ray scattering. The R _g values and the Kratky plots showed that non-reduced ribonuclease A maintain a compact shape with a R _g value of about 17.3 Å in 8 M urea. The reduced ribonuclease A is more expanded, its R _g value is about 20 Å in 50 mM Tris-HCl buffer at pH 8.1 containing 20 mM DTT. Further expansions of reduced ribonuclease A were observed in the presence of high concentrations of denaturants, indicating that reduced ribonuclease A is more expanded and is in neither a random coil [A. Noppert et al., FEBS Lett. 380 (1996) 179–182] nor a compact denatured state [T.R. Sosnick and J. Trewhella, Biochemistry 31 (1992) 8329–8335]. The four disulfide bonds keep ribonuclease A in a compact state in the presence of high concentrations of urea.

【 授权许可】

Unknown