Location

Portland State University

Start Date

7-5-2019 11:00 AM

End Date

7-5-2019 1:00 PM

Subjects

Hyperthermophilic organisms, Capsid proteins, Viruses -- Purification, Protein precursors, Archaebacteria -- Viruses

Abstract

Unique lemon-shaped viruses, the Fuselloviridae, or Sulfolobus Spindle-Shaped Viruses (SSVs) of hyperthermophilic archaea are characterized by both their unusual structure and extreme thermal tolerance. The most well characterized of the SSVs is SSV1. Wild-type SSV1 tolerates multiple mutations to its genome while still remaining infectious, making this virus ideal to study molecular processes in extreme environments. The major capsid protein, VP1 forms the unique structure of the virus and provides protection for the genome. The amino terminus of the VP1 protein purified from wild-type SSV1 is glutamate 66 (E66) indicating proteolytic cleavage. E66 is universally conserved in all SSVs. Interestingly, the N-terminus of VP1 upstream of E66 which is cleaved off is required for infectivity, indicating that VP1 may be made or assembled as a precursor protein. Virus mutants made by single point mutations at E66 in VP1 in SSV1, changing the glutamate to either alanine or glutamine produces infectious virus which displays the traditional lemon-shape morphology that varies slightly in structure from wild-type. This work aims to determine whether these mutant viruses are cleaved at the same location (66) as the wild-type or cleaved elsewhere. To determine the location these mutant viruses are proteolytically processed, whole virus purification of mutant SSV1 virus and N-terminus sequencing will be performed. Ultimately, the role of proteolytic cleavage in virus assembly and structure will be determined.

Persistent Identifier

https://archives.pdx.edu/ds/psu/28604

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May 7th, 11:00 AM May 7th, 1:00 PM

Amino-terminal Sequencing of SSV1 Major Capsid Protein VP1 Mutants

Portland State University

Unique lemon-shaped viruses, the Fuselloviridae, or Sulfolobus Spindle-Shaped Viruses (SSVs) of hyperthermophilic archaea are characterized by both their unusual structure and extreme thermal tolerance. The most well characterized of the SSVs is SSV1. Wild-type SSV1 tolerates multiple mutations to its genome while still remaining infectious, making this virus ideal to study molecular processes in extreme environments. The major capsid protein, VP1 forms the unique structure of the virus and provides protection for the genome. The amino terminus of the VP1 protein purified from wild-type SSV1 is glutamate 66 (E66) indicating proteolytic cleavage. E66 is universally conserved in all SSVs. Interestingly, the N-terminus of VP1 upstream of E66 which is cleaved off is required for infectivity, indicating that VP1 may be made or assembled as a precursor protein. Virus mutants made by single point mutations at E66 in VP1 in SSV1, changing the glutamate to either alanine or glutamine produces infectious virus which displays the traditional lemon-shape morphology that varies slightly in structure from wild-type. This work aims to determine whether these mutant viruses are cleaved at the same location (66) as the wild-type or cleaved elsewhere. To determine the location these mutant viruses are proteolytically processed, whole virus purification of mutant SSV1 virus and N-terminus sequencing will be performed. Ultimately, the role of proteolytic cleavage in virus assembly and structure will be determined.