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May 1, 2014

Bayse Selenium Research Takes Aim at Diseases

morenews1-lgCraig Bayse
By Jim Raper

Craig Bayse, professor and graduate program director in Old Dominion's Department of Chemistry and Biochemistry, is an author of an article in the prestigious journal Proceedings of the National Academy of Sciences (PNAS) April 21 that reports new understanding of how the chemical selenium is able to do so much good within the human body.

Proteins containing selenium, or selenoproteins, use the rare amino acid selenocysteine to act as the first line of defense against oxidants, which are linked to aging, cancer and neurodegenerative diseases such as Alzheimer's. Selenoproteins "are rare [but] they are essential for mammals and have important roles in antioxidant defense," the article says.

Selenium, which is found in onions, garlic and Brazil nuts, is present in only trace quantities in the body. "Selenium is endlessly fascinating because we need only small quantities to be healthy, but too much can have a negative effect. We are looking at its fundamental properties to understand why some proteins use it instead of sulfur, its less toxic and more available cousin," Bayse said.

Bayse and an international team of researchers set out to answer some of these questions by using a new regimen of nuclear magnetic resonance (NMR) spectroscopy to spy on chemical reactions involving selenium and in conjunction with theoretical calculations to zero in on properties never before revealed.

"In redox biology, the chemistry performed by proteins that contain the rare amino acid selenocysteine is frequently critical to the detoxification of reactive species that are harmful to cellular function," the PNAS article states. "Selenocysteine and cysteine partner to form a motif featuring a sulfur-selenium covalent bond in many selenoproteins. This work demonstrates that selenium NMR, when paired with calculations, can provide critical new insight concerning the local environment of these enigmatic redox motifs."

Sharon Rozovsky, a biochemist at the University of Delaware, leads the research team along with Bayse. Other authors of the PNAS article, which is titled "Redox Active Motifs in Selenoproteins," are Fei Li, a current graduate researcher at UD, and Yuliya Pepelyayeva, a former graduate researcher at UD; Patricia B. Lutz, a graduate researcher at ODU; and Elias S.J. Arner of Karolinska Institutet in Sweden.

Bayse is a veteran selenium researcher and his work has been supported by the National Science Foundation (NSF). One thrust of his work has been to study how selenium affects biochemical signaling in the human body. The research relates to the potential use of selenium to fight cancer and cardiovascular disease.

Bayse's theoretical studies in recent years have shed light on the biological activity - and antioxidant properties - of selenium. But the use of selenium has been limited by its potential disruption of normal biochemical signaling pathways, especially those that are zinc-mediated and lead to such beneficial outcomes as DNA repair. Bayse has used molecular modeling to determine the mechanisms of both the beneficial and harmful effects of selenium.

An NSF news release about a grant supporting Bayse's work stated, "The long-term, broader impacts of this award relate to the potential role selenium may have in the prevention of cancer and cardiovascular disease; the results in the long term may guide the development of chemotherapeutic agents."

Bayse joined the ODU faculty in 2001.