Research articles
ScienceAsia (): 100-104 |doi:
10.2306/scienceasia1513-1874...100
The putative thiol-disulphide interchange protein DsbG from Acidithiobacillus ferrooxidans has disulphide isomerase activity
Cheng-gui Zhanga,b, Jin-lan Xiaa,*, Yuan-dong Liua, Huan Hea, Guan-zhou Qiua
ABSTRACT: The putative thiol-disulphide interchange protein, DsbG, is involved in the formation and rearrangement of disulphide bonds in Acidithiobacillus ferrooxidans but its exact role is so far unclear. The gene encoding DsbG from A. ferrooxidans ATCC 23270 was cloned and expressed in Escherichia coli BL21 (DE3). The protein was purified by one-step affinity chromatography. The scRNaseA could be rescued to 89% of the native RNaseA activity by using the purified DsbG of A. ferrooxidans. This characteristic is unique and different from that of DsbG from E. coli, which does not catalyse the oxidative refolding of RNaseA in vitro. Site-directed mutagenesis of the DsbG protein revealed that Cys119A and Cys122A do not possess the disulphide isomerization activity, indicating Cys119 and Cys122 are catalytic residues and play a crucial role in disulphide isomerization.
Download PDF
0 Downloads 1298 Views
| a |
Key Lab of Biometallurgy of the Ministry of Education of China, School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China |
| b |
Faculty of Pharmacy, Dali University, Dali 671000, China |
* Corresponding author, E-mail: jlxia@mail.csu.edu.cn
Received 18 Aug 2009, Accepted 26 Mar 2010
|
