Please join us for our next speaker in the 2015 Evergreen PLATO Lecture Series. The talk will be on Friday, May 22nd, 2015 in Lecture Hall 1 from 12-1 pm.
Please consider announcing this to your students and colleagues. There will be many more of these lectures in Spring quarter. They are planned for the lunch hour on Fridays on the Evergreen Campus. The seminar series is funded by a grant from the royalties received from the PLATO computer-aided instruction materials developed at Evergreen during the early 1980s. PLATO grants support an annual seminar series and technology proposals.
PLATO Lecture Series 2015
Computer-aided Environmental Science; Fridays 12-1 pm in Lecture Hall 1
“How structural bioinformatics helped reveal the biomolecular origins of a potent neurotoxin”
Friday May 22, 2015: Dr. Alex Johs from Oak Ridge National Labs, Center for Molecular Biophysics
Mercury is a pervasive global pollutant that poses a substantial threat to human health. Methylmercury is a highly potent neurotoxin and bioaccumulates up trophic levels. Consumption of fish is the principal form of Hg exposure to humans. One particular concern is the impact of methylmercury on the intellectual development in children. Despite significant research efforts, the biochemistry of mercury methylation has remained elusive for more than 40 years. I will discuss how we used structural bioinformatics to identify a two-gene cluster required for mercury methylation in anaerobic bacteria. The genes encode a B12-dependent membrane protein, HgcA, and a 2[4Fe-4S] ferredoxin, HgcB, consistent with roles as methyl carrier and electron donor required for B12 cofactor reduction, respectively. Gene orthologs are present in all confirmed methylators but absent in nonmethylators, suggesting a mercury methylation pathway common to all methylating bacteria and archaea. Homology modeling, quantum chemical calculations, UV-Vis and EXAFS spectroscopy are consistent with an unprecedented coordination of a cysteine thiolate to the cobalt center of B12. The present results suggest that this unique configuration could facilitate transfer of a formal methyl carbanion to mercury resulting in the formation of toxic methylmercury.
To learn more about Dr. Johs’ research, please visit his website:
Carri J. LeRoy, Ph.D.
Member of the Faculty, Freshwater Ecology
The Evergreen State College
2700 Evergreen Parkway NW
Lab 2, 3261
Olympia, WA 98505
Tel: 360-867-5483