| Title |
Periplasmic Domain of CusA in an Escherichia coli Cu+/Ag+ Transporter Has Metal Binding Sites |
| Author |
Bo-Young Yun1, Yongbin Xu1, Shunfu Piao1, Nahee Kim2, Jeong-Hyun Yoon1, Hyun-Soo Cho2, Kangseok Lee3, and Nam-Chul Ha1* |
| Address |
1College of Pharmacy and Research Institute for Drug Development, Pusan National University, Busan 609-735, Republic of Korea, 2Department of Biology, College of Science, Yonsei University, Seoul 120-749, Republic of Korea, 3Department of Life Science, Chung-Ang University, Seoul 156-756, Republic of Korea |
| Bibliography |
Journal of Microbiology, 48(6),829-835, 2010,
|
| DOI |
|
| Key Words |
membrane protein, metal efflux pump, Gram-negative bacteria, RND-type transporter |
| Abstract |
The resistance nodulation division (RND)-type efflux systems are utilized in Gram-negative bacteria to export a variety of substrates. The CusCFBA system is the Cu+ and Ag+ efflux system in Escherichia coli, conferring resistance to lethal concentrations of Cu+ and Ag+. The periplasmic component, CusB, which is
essential for the assembly of the protein complex, has Cu+ or Ag+ binding sites. The twelve-span membrane protein CusA is a homotrimeric transporter, and has a relatively large periplasmic domain. Here, we constructed the periplasmic domain of CusA by joining two DNA segments and then successfully expressed and purified the protein. Isothermal titration calorimetry experiments revealed Ag+ binding sites with Kds of 10-6-10-5 M. Our findings suggest that the metal binding in the periplasmic domain of CusA might play an important role in the function of the efflux pump. |
