Role of protein conformation in the processing of dengue virus type 2 nonstructural polyprotein precursor

Luwen Zhang, R. Padmanabhan

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

The dengue virus type-2 (DEN-2) genome is a positive-strand RNA encoding a single polyprotein precursor, C-prM(M)-E-NSl-NS2A-NS2B-NS3-NS4A-NS4B-NS5, consisting of 3391 amino acids (aa). The N-terminal region of the polyprotein precursor, C-prM(M)-E, encodes the structural proteins and is processed cotranslationally by the host signal peptidase. The nonstructural region NS1→ NS5 is processed by the viral protease(s), as well as by the signal peptidase. A two-component viral protease consisting of NS2B and the serine protease domain of NS3 has been shown to be required for cleavages having the consensus sequence of dibasic aa (K-R, R-R, R-K, or Q-R). In this study, the region encoding all the nonstructural proteins, NS1→ NS5, was expressed using a recombinant vaccinia virus system. Cleavages at the consensus viral protease recognition sites, 2B-3 at the N terminus and 3-4A at the C terminus, are prerequisites to the release of mature NS3 protease. Although the 2B-3 site was cleaved readily in a variety of polyprotein precursors containing the intact NS2B and the NS3 protease domain, the 3-4A site was most efficiently cleaved, similar to that found in DEN-2-infected cells, only in the polyprotein precursor encoding the entire nonstructural region. Removal of NSI at the N terminus or of NS5 coding sequences at the C terminus affected the cleavage at the 3-4A site to produce the processing intermediate, NS3-NS4A. These results indicate that the conformation of the nonstructural polyprotein precursor, NS1→ NS5, plays a major role in the efficient cleavage at the 3-4A site.

Original languageEnglish (US)
Pages (from-to)197-205
Number of pages9
JournalGene
Volume129
Issue number2
DOIs
Publication statusPublished - Jul 30 1993

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Keywords

  • RNA-dependent RNA polymerase
  • Recombinant DNA
  • T7 promoter
  • cap-independent translation
  • encephalomyocarditis virus 5'-untranslated leader
  • flavivirus
  • polyprotein processing
  • positive-strand RNA virus
  • serine protease
  • vaccinia virus

ASJC Scopus subject areas

  • Genetics

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