3C-like protease of rabbit hemorrhagic disease virus: identification of cleavage sites in the ORF1 polyprotein and analysis of cleavage specificity.
AUTOR(ES)
Wirblich, C
RESUMO
Rabbit hemorrhagic disease virus, a positive-stranded RNA virus of the family Caliciviridae, encodes a trypsin-like cysteine protease as part of a large polyprotein. Upon expression in Escherichia coli, the protease releases itself from larger precursors by proteolytic cleavages at its N and C termini. Both cleavage sites were determined by N-terminal sequence analysis of the cleavage products. Cleavage at the N terminus of the protease occurred with high efficiency at an EG dipeptide at positions 1108 and 1109. Cleavage at the C terminus of the protease occurred with low efficiency at an ET dipeptide at positions 1251 and 1252. To study the cleavage specificity of the protease, amino acid substitutions were introduced at the P2, P1, and P1' positions at the cleavage site at the N-terminal boundary of the protease. This analysis showed that the amino acid at the P1 position is the most important determinant for substrate recognition. Only glutamic acid, glutamine, and aspartic acid were tolerated at this position. At the P1' position, glycine, serine, and alanine were the preferred substrates of the protease, but a number of amino acids with larger side chains were also tolerated. Substitutions at the P2 position had only little effect on the cleavage efficiency. Cell-free expression of the C-terminal half of the ORF1 polyprotein showed that the protease catalyzes cleavage at the junction of the RNA polymerase and the capsid protein. An EG dipeptide at positions 1767 and 1768 was identified as the putative cleavage site. Our data show that rabbit hemorrhagic disease virus encodes a trypsin-like cysteine protease that is similar to 3C proteases with regard to function and specificity but is more similar to 2A proteases with regard to size.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=189637Documentos Relacionados
- Polyprotein processing in Southampton virus: identification of 3C-like protease cleavage sites by in vitro mutagenesis.
- Identification and characterization of a 3C-like protease from rabbit hemorrhagic disease virus, a calicivirus.
- Identification of Active-Site Amino Acid Residues in the Chiba Virus 3C-Like Protease
- Mouse Hepatitis Virus 3C-Like Protease Cleaves a 22-Kilodalton Protein from the Open Reading Frame 1a Polyprotein in Virus-Infected Cells and In Vitro
- Processing of the Human Coronavirus 229E Replicase Polyproteins by the Virus-Encoded 3C-Like Proteinase: Identification of Proteolytic Products and Cleavage Sites Common to pp1a and pp1ab