Why arsenic can be deadly, yet also function as theapeutic against disease

This information not only opens the doors to developing safer therapeutic alternatives to arsenite-based medicines, but it may allow researchers counter the negative effects of arsenite poisoning.

"By better understanding arsenite, we might be able to protect humans from its hazards in the future," said Jef D. Boeke, Ph.D., co-author of the study from the Department of Molecular Biology and Genetics and The High Throughput Biology Center at The Johns Hopkins University School of Medicine in Baltimore. "Arsenite also has beneficial effects, and by focusing on these, we might be able to find safer ways to reap the beneficial effects without the inherent risks involved in using a compound derived from arsenic."

To make this discovery, scientists used advanced genomic tools and biochemical experiments to show that arsenic disturbs functions of the machinery (chaperonin complex) required for proper folding and maturation of several proteins and protein complexes within yeast cells. This mechanism of action by arsenic is not unique to yeast, as it has been shown to exist in a range of organisms from bacteria to mammals.

"As the human population grows, freshwater supplies become increasingly precious, but unfortunately some of this water has been contaminated with arsenite," said Mark Johnston, Editor-in-Chief of the journal Genetics. "The more we learn about how this compound affects our bodies, the more we'll eventually be able to counter its deadly effects. In addition, we know that under certain controlled doses, arsenite has therapeutic value. This research hopefully gets us closer to a new generation of drugs that achieve maximum benefit with minimum risk."