Structural kinetics of the allosteric transition of aspartate transcarbamylase produced by physiological substrates

FEBS Letters

Moody, Michael F.¹  Kimura, Kazumoto³  Tsuruta, Hirotsugu²  Vachette, Patrice⁶  Taue, Patrick⁴  Kihara, Hiroshi⁵  Amemiya, Yoshiyuki⁷  Wakabayashi, Katsuzo⁸  Sano, Takayuki² 

[1] School of Pharmacy, University of London, 29/39 Brunswick Square, London WC1N 1AX England;Department of Materials Science, Faculty of Science, Hiroshima University, Higashisenda, Hiroshima 730, Japan;Division of Medical Electronics, Dokkyo University, School of Medicine, Mibu, Tochigi 321-02 Japan;Institut d'Enzymologie, CNRS F91190 Gif-sur- Yvette, France,;Jichi Medical School, School of Nursing, Minamikawachi, Tochiga 329-04, Japan;LURE, Bâtiment 209d, Université Paris-sud, F91405 Orsay Cedex, France;Photon Factory, National Laboratory for High Energy Physics Oho, Tsukuba 305, Japan;Department of Biophysical Engineering, Faculty of Engineering Science, Osaka University, Machikaneyama, Toyonaka 560, Japan

关键词: Allostery;    Aspartate transcarbamylase;    Fast kinetics;    X-ray scattering;   

DOI  :  10.1016/0014-5793(90)80706-O

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We have studied the kinetics of the quaternary structure change associated with the allosteric transition of aspartate transcarbamylase (ATCase) (E. coli), inducing this change by exposure to the natural substrates (carbarnyl phosphate and L-aspartate). The presence of 30% ethylene glycol slowed the quaternary structure change sufficiently for it to be followed by stopped-flow X-ray scattering at − 5°C. After adding substrates to the enzyme, the change occurred, with a half-life of a few seconds, yielding a mixture of the two standard quaternary structures (or, conceivably, a state intermediate between them). This mixture persisted until the enzyme reduced the substrate concentration below a threshold value.

【 授权许可】

Unknown