Expression, purification and crystallization of VP4 protease from Tellina virus 1
Tellina virus 1 is an aquabirnavirus that was isolated from the sand‐dwelling marine bivalve mollusc Tellina tenuis. The self‐encoded protease viral protein 4 (VP4) processes its own polyprotein to yield the individual proteins VP2 and VP3 that are required for viral assembly. VP4 protease utilizes a serine–lysine catalytic dyad in its mechanism. A full‐length VP4 construct was overexpressed in Escherichia coli and purified to homogeneity using nickel‐affinity chromatography. Ion‐exchange and size‐exclusion chromatographic steps were utilized to isolate a monomeric fraction of the protein. The purified monomeric VP4 was subjected to limited proteolysis to yield crystallizable protein. Crystal growth was performed using the hanging‐drop vapour‐diffusion method and was carried out at room temperature (∼296 K). Hexagonal crystals grew in the presence of PEG 8000, ammonium sulfate and urea. These crystals diffracted to beyond 2.1 Å resolution and belonged to space group P6422, with unit‐cell parameters a = 59.1, b = 59.1, c = 208.1 Å, one molecule in the asymmetric unit and a solvent content of 42%.
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Document Type: Research Article
Affiliations: Department of Molecular Biology and Biochemistry, Simon Fraser University, South Science Building, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
Publication date: January 1, 2011