Originally published as JGV in Press, 10.1099/vir.0.011296-0 on May 13, 2009
J Gen Virol 90 (2009), 2114-2118; DOI 10.1099/vir.0.011296-0
Functional differences between precursor and mature forms of the RNA-dependent RNA polymerase from rabbit hemorrhagic disease virus
Ángeles Machín,
José M. Martín Alonso,
Kevin P. Dalton and
Francisco Parra
Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Biotecnología de Asturias, Universidad de Oviedo, 33006 Oviedo, Spain
Correspondence
Francisco Parra
fparra{at}uniovi.es
The genome region encoding the RNA-dependent RNA polymerase 3CD-like precursor from rabbit hemorrhagic disease virus (RHDV) (isolate AST/89) was cloned and expressed in Escherichia coli using polyhistidine fusion-based vectors. The full-length recombinant 3CD-like precursor polypeptide could not be purified as a consequence of its autoproteolytic processing. A Cys
Gly substitution of the 3C-like catalytic cysteine (C1212) impeded the cleavage and allowed the purification of the precursor at high yields using a polyhistidine fusion expression vector. Equimolar amounts of purified recombinant precursor (C1212G mutant) and mature 3D-like polymerase showed significant activity differences in genome-linked protein (VPg) uridylylation and RNA polymerization using in vitro assays. The data indicated that the precursor was more active than the mature polymerase in catalysing RHDV VPg uridylylation, whereas the latter enzyme form had higher activity than its precursor in RNA polymerization in vitro assays using a heteropolymeric RNA template.
Copyright © 2009 by the Society for General Microbiology.