Scientists at The Scripps Research Institute have determined the structure of a critical protein from the Ebola virus, called VP35. The research reveals how this component masks the double-stranded RNA, which would usually serve as an alert to the immune system, allowing the virus uncontrolled replication.
The details are described in the advance, online early edition of Proceedings of the National Academy of Sciences (PNAS) in an article titled “Ebola virus VP35 uses a bimodal strategy to bind dsRNA for innate immune suppression.”
The protein structure, determined by x-ray crystallography, showed that VP35 binds another copy of itself, and the pair cooperatively masks the RNA ends. This assembly is unusual because each member of the pair binds the RNA in a different way, revealing that VP35 has two unique strategies for masking viral signatures, explains Christopher Kimberlin, the first author of this study.
Additional RNA binding, small angle x-ray scattering, and deuterium exchange mass spectrometry experiments confirmed the cooperative function of these molecules for immunosuppression.