Marburg Virus VP35 Can Both Fully Coat the Backbone and Cap the Ends of dsRNA for Interferon Antagonism

PLoS Pathogens

Christopher R. Kimberlin¹  Michelle A. Zandonatti¹  Zachary A. Bornholdt¹  Shridhar Bale¹  Gerard J. A. Kroon²  Jean-Philippe Julien²  Erica Ollmann Saphire²  John Kunert³  Peter Halfmann³  Yoshihiro Kawaoka³  Ian J. MacRae⁴  Ian A. Wilson⁵ 

[1]Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America

[2]Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America

[3]Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, United States of America

[4]Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo, Japan

[5]International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo, Japan

关键词: Crystal structure;    Crystallization;    Crystals;    Binding analysis;    Filoviruses;    Hydrogen bonding;    Marburg virus;    Molecular structure;   

DOI  :  10.1371/journal.ppat.1002916

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Filoviruses, including Marburg virus (MARV) and Ebola virus (EBOV), cause fatal hemorrhagic fever in humans and non-human primates. All filoviruses encode a unique multi-functional protein termed VP35. The C-terminal double-stranded (ds)RNA-binding domain (RBD) of VP35 has been implicated in interferon antagonism and immune evasion. Crystal structures of the VP35 RBD from two ebolaviruses have previously demonstrated that the viral protein caps the ends of dsRNA. However, it is not yet understood how the expanses of dsRNA backbone, between the ends, are masked from immune surveillance during filovirus infection. Here, we report the crystal structure of MARV VP35 RBD bound to dsRNA. In the crystal structure, molecules of dsRNA stack end-to-end to form a pseudo-continuous oligonucleotide. This oligonucleotide is continuously and completely coated along its sugar-phosphate backbone by the MARV VP35 RBD. Analysis of dsRNA binding by dot-blot and isothermal titration calorimetry reveals that multiple copies of MARV VP35 RBD can indeed bind the dsRNA sugar-phosphate backbone in a cooperative manner in solution. Further, MARV VP35 RBD can also cap the ends of the dsRNA in solution, although this arrangement was not captured in crystals. Together, these studies suggest that MARV VP35 can both coat the backbone and cap the ends, and that for MARV, coating of the dsRNA backbone may be an essential mechanism by which dsRNA is masked from backbone-sensing immune surveillance molecules.

【 授权许可】

CC BY