The MerE protein encoded by transposon Tn21 is a broad mercury transporter in Escherichia coli

Kiyono, Masako; Sone, Yuka; Nakamura, Ryosuke; Pan-Hou, Hidemitsu; Sakabe, Kou

doi:10.1016/j.febslet.2009.02.039

« Previous Next »FEBS Letters
Volume 583, Issue 7 , Pages 1127-1131, 2 April 2009

The MerE protein encoded by transposon Tn21 is a broad mercury transporter in Escherichia coli

Masako Kiyono
- Department of Public Health and Molecular Toxicology, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
- Corresponding author.
Yuka Sone
- Department of Public Health and Molecular Toxicology, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
Ryosuke Nakamura
- Department of Public Health and Molecular Toxicology, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
Hidemitsu Pan-Hou
- Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan
Kou Sakabe
- Department of Public Health and Molecular Toxicology, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan

Received 10 January 2009; received in revised form 24 February 2009; accepted 25 February 2009. published online 03 March 2009.

Edited by Renee Tsolis

Abstract

In order to clarify the physiological role of the merE gene of transposon Tn21, a pE4 plasmid that contained the merR gene of plasmid pMR26 from Pseudomonas strain K-62, and the merE gene of Tn21 from the Shigella flexneri plasmid NR1 (R100) was constructed. Bacteria with plasmid pE4 (merR-o/p-merE) were more hypersensitive to CH₃Hg(I) and Hg(II), and took up significantly more CH₃Hg(I) and Hg(II), than the isogenic strain. The MerE protein encoded by pE4 was localized in the membrane cell fraction, but not in the soluble fraction. Based on these experimental results, we suggest for the first time that the merE gene is a broad mercury transporter mediating the transport of both CH₃Hg(I) and Hg(II) across the bacterial membrane.