Probing changes in Hg(II) coordination during its bacterial uptake

Sara Anne Thomas, Qing Ma, Jean François Gaillard

Research output: Contribution to journalConference articlepeer-review

2 Scopus citations

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 languageEnglish (US)
Article number012078
JournalJournal of Physics: Conference Series
Volume712
Issue number1
DOIs
StatePublished - 2016
Event16th International Conference on X-Ray Absorption Fine Structure, XAFS 2015 - Karlsruhe, Germany
Duration: Aug 23 2015Aug 28 2015

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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