The mechanism of the molecular interaction between cerium (III) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco).
The mechanism of the molecular interaction between Ce3+, a member of rare earth elements, and Rubisco in vitro is investigated. The carboxylase activity of Rubisco greatly increased under low concentrations of Ce3+ and decreased under high concentrations of Ce3+. The ultraviolet absorption spectra show that the various concentrations of Ce3+ treatment do not shift the characteristic peaks of Rubisco while the characteristic peak intensity of Rubisco increases with increasing Ce3+ concentration. The Rubisco-Ce3+ interactions also do not cause any noticeable change in the λmax of Rubisco fluorescence spectra. However, the fluorescence intensity of Rubisco is found quenched by the addition of Ce3+, which strongly suggests that Ce3+ could directly bind to the Rubisco protein. and the binding sites is estimated to 1.52 per protein. The binding between Ce3+ and Rubisco is also proved by extended X-ray absorption fine-structure essay; Ce3+ coordinated with eight oxygen atoms of Rubisco in first shells and six oxygen atoms in second shells. The results implied that Ce3+ might improve the microenvironment of Rubisco and, in turn, affected the carboxylase capacity of Rubisco greatly.
Medical College, Soochow University, Suzhou, 215123, China.
Chao
C
Liu
Fa-shui
FS
Hong
Ye
Y
Tao
Tao
T
Liu
Ya-ning
YN
Xie
Jian-hua
JH
Xu
Zhong-rui
ZR
Li
D002563:Cerium / Q000378:metabolism*; D011485:Protein Binding; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet
D002563:Cerium; D012273:Ribulose-Bisphosphate Carboxylase