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The compactness of ribonuclease A and reduced ribonuclease A
Author(s) -
Zhou Jun-Mei,
Fan Ying-Xin,
Kihara Hiroshi,
Kimura Kazumoto,
Amemiya Yoshiyuki
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00639-5
Subject(s) - ribonuclease , chemistry , random coil , urea , crystallography , ribonuclease iii , s tag , native state , pancreatic ribonuclease , biochemistry , rna , circular dichroism , rna interference , gene
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.