Alphaviruses are enveloped, positive strand RNA viruses that are capable of causing a variety of symptoms including arthritis, encephalitis, and even death in humans. Chikungunya virus, a member of the alphavirus genus, is a recently emerging pathogen in the Americas with over one million suspected cases in the Americas in 2014. There is no specific anti-viral treatment or vaccine against any member of the alphavirus genus. The viral nonstructural proteins (nsP1-4) responsible for viral RNA replication are produced as a polyprotein. RNA replication complex template usage is regulated by proteolytic processing of the nonstructural polyproteins. Information about the rearrangement of viral proteins before and after cleavage is essential to understanding of the progression of viral pathogenesis. After cleavage, the mature nsPs each assume individual functions in the RNA replication complex or elsewhere for productive infection. We described a portion of alphavirus polyprotein P23 from Sindbis virus and chikungunya virus. The structures show four domains each occupying a vertex of a rectangle. A 40 Ă… distance between the nsP2 protease and P2/3 cleavage site supports the proposed trans cleavage mechanism. Our P23 structure was used for ligand docking and will be a useful tool in the development of unique anti-viral therapies. Thus far, nsP3 is the least understood alphavirus protein. In the polyprotein, nsP3 forms an extended linker, encircling nsP2, connecting its two domains, important in efficient polyprotein processing and the progression of infection. The P23 structure also revealed a novel zinc binding domain of nsP3 necessary for viral infection. Further biochemical study indicates a role for nsP3 in regulating nsP2 ATP hydrolysis activity. Additionally, nsP3 macrodomain has been shown to bind ADP-ribose but the significance of this during infection is unknown. Abolishing ADP-ribose binding has a significant negative effect on replication in insect cells, whereas previously only the nsP3 C-terminal region was known to mediate infection in various host cells. Overall, our strategy of describing alphavirus nsPs with regard to their structure and activities pre- and post-cleavage via biophysical, biochemical, and virological methods has significantly contributed to a better understanding of viral pathogenesis and present opportunities for novel anti-viral therapy design.
Subject (authority = RUETD)
Topic
Microbiology and Molecular Genetics
Subject (authority = ETD-LCSH)
Topic
Virology
RelatedItem (type = host)
TitleInfo
Title
Rutgers University Electronic Theses and Dissertations
Identifier (type = RULIB)
ETD
RelatedItem (type = host)
TitleInfo
Title
Graduate School - New Brunswick Electronic Theses and Dissertations
Identifier (type = local)
rucore19991600001
Identifier
ETD_7072
Identifier (type = doi)
doi:10.7282/T38C9ZF6
PhysicalDescription
Form (authority = gmd)
electronic resource
InternetMediaType
application/pdf
InternetMediaType
text/xml
Extent
1 online resource (xiv, 112 p. : ill.)
Note (type = degree)
Ph.D.
Note (type = bibliography)
Includes bibliographical references
Note (type = statement of responsibility)
by Samantha Alexis Yost
Location
PhysicalLocation (authority = marcorg); (displayLabel = Rutgers, The State University of New Jersey)
Rutgers University. Graduate School - New Brunswick
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Type
License
Name
Author Agreement License
Detail
I hereby grant to the Rutgers University Libraries and to my school the non-exclusive right to archive, reproduce and distribute my thesis or dissertation, in whole or in part, and/or my abstract, in whole or in part, in and from an electronic format, subject to the release date subsequently stipulated in this submittal form and approved by my school. I represent and stipulate that the thesis or dissertation and its abstract are my original work, that they do not infringe or violate any rights of others, and that I make these grants as the sole owner of the rights to my thesis or dissertation and its abstract. I represent that I have obtained written permissions, when necessary, from the owner(s) of each third party copyrighted matter to be included in my thesis or dissertation and will supply copies of such upon request by my school. I acknowledge that RU ETD and my school will not distribute my thesis or dissertation or its abstract if, in their reasonable judgment, they believe all such rights have not been secured. I acknowledge that I retain ownership rights to the copyright of my work. I also retain the right to use all or part of this thesis or dissertation in future works, such as articles or books.