Researchers shut down SARS cloaking system

A Purdue University-led research team has figured out how to disable a part of the SARS virus responsible for hiding it from the immune system -- a critical step in developing a vaccine against the deadly disease.

The findings also have potential applications in the creation of vaccines against other coronaviruses, including MERS, said Andrew Mesecar, who led the research.

"This is a first step toward creating a weakened and safe virus for use in an attenuated live vaccine," said Mesecar, Purdue's Walther Professor of Cancer Structural Biology and professor of biological sciences and chemistry. "This also could serve as a molecular roadmap for performing similar studies on other coronaviruses, like MERS, because this enzyme appears to be common to all viruses within this family."

Mesecar also is a part of a research team studying and creating potential treatment compounds for the Middle East respiratory syndrome coronavirus, or MERS, that recently arrived in the United States. There is currently no treatment or vaccine for the virus, which has an estimated fatality rate of 30 percent, according to the Centers for Disease Control and Prevention.

Because MERS and SARS are related, insight into one could provide a shortcut to finding a treatment or developing a vaccine for the other.

Mesecar and his team captured the molecular structure of a key SARS enzyme, papain-like protease, and revealed how it strips a host cell of the proteins ubiquitin and ISG15, which are involved in triggering an immune response.