Abstract
We present XAFS data collected at the Hg LIII-edge for bacterial cells of Escherichia coli that have been exposed to 500 and 50 nano-molar Hg2+ in aqueous solution, which corresponds to ∼30 and ∼3μg Hg per g cells (wet weight). These concentrations are respectively 1 and 2 orders of magnitude lower than what has been previously reported for Hg-bacteria XAFS experiments. The cells were metabolically active while exposed to Hg(II), providing coordination information that can be directly compared to Hg(II) biouptake experiments. At these amounts of total dissolved metal, Hg(II) binds primarily to thiol moieties that are either present at the cell membrane or localized in the cytoplasm. We show that in this case the Hg binding environment is a mixture of 2- and 4-fold coordination to thiols. This information can be inferred from XANES spectra but the EXAFS provides a more quantitative answer.
| Original language | English (US) |
|---|---|
| Article number | 012078 |
| Journal | Journal of Physics: Conference Series |
| Volume | 712 |
| Issue number | 1 |
| DOIs | |
| State | Published - 2016 |
| Event | 16th International Conference on X-Ray Absorption Fine Structure, XAFS 2015 - Karlsruhe, Germany Duration: Aug 23 2015 → Aug 28 2015 |
Funding
This work is supported by the National Science Foundation under grant CHE-1308504. Portions of this work were performed at the DND-CAT Synchrotron Research Center located at Sector 5 of the APS. DND-CAT is supported by the E.I. DuPont de Nemours & Co., The Dow Chemical Company, the U.S. National Science Foundation through Grant DMR-9304725, and the State of Illinois through the Department of Commerce and the Board of Higher Education Grant IBHE HECA NWU 96.
ASJC Scopus subject areas
- General Physics and Astronomy