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標題: Endopeptidase activity characterization of E. coli-derived infectious bursal disease virus protein 4 tubules
作者: Chang, Gary Ro-Lin
Wang, Min-Ying
Liao, Jiahn-Haur
Hsiao, Yu-Ping
Lai, Su-Yuan
Project: Protein Engineering, Design and Selection, Volume 25, Issue 11, Page(s) 789-795.
Viral protein 4 (VP4) is a serine protease that catalyzes the
hydrolysis of polyprotein pVP2-VP4-VP3 of infectious
bursal disease virus. In this report, the recombinant
VP4 with a His-tag and three mutants (VP4-S652A,
VP4-K692A and VP4-S652A.K692A) were expressed in
Escherichia coli. Soluble VP4 was purified using immobilized
metal-ion affinity chromatography or sucrose density
gradient following with gel-filtration chromatography. The
purified VP4 has a tubular structure with 25–30 nm in
width and ∼300 nm in length, as observed by transmission
electron microscope. A similar tubular structure was
also found for these three mutants. The endopeptidase
activity of these VP4 tubules was characterized by fluorescence
resonance energy transfer using a synthetic fluorogenic
oligopeptide as a substrate. The results show that the
tubule-like VP4 is a functional enzyme with Km of 43+
2 mM and kcat of 0.04+0.01 min21; however, kcat of three
mutants were significantly reduced. This is the first report
to demonstrate that VP4 protein expressed in E. coli can
self-assemble into functional tubule-like particles and its
activity can be completely inhibited by 1 mM of Ni12 ions.
Keywords: endopeptidase activity/immobilized metal-ion
affinity chromatography (IMAC)/infectious bursal disease
virus/nickel ions/Ser/Lys dyad/tubule-like particles
ISSN: 1741-0126
DOI: 10.1093/protein/gzs087
Appears in Collections:生命科學系所

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