Protein 3CD is the major poliovirus proteinase responsible for cleavage of the P1 capsid precursor.
The rate and extent of polyprotein processing are the major steps controlling picornavirus gene expression. It is, therefore, important to determine the enzymes responsible for each proteolytic event. The poliovirus protein 3C has been identified as a proteinase which specifically cleaves between Q-G pairs. However, recent data have suggested that 3C precursor polypeptides containing 3C sequences may also have proteolytic capabilities. In this study we have analyzed the cleavage specificities of protein 3C and its precursor, 3CD. We have carried out in vitro translation of genetically altered poliovirus mRNAs to demonstrate that 3CD is required for efficient processing of the P1 capsid precursor to capsid proteins. In addition, we suggest 3CD and 3C process Q-G pairs in the P2 and P3 precursors with similar efficiencies.
Ypma-Wong
M F
MF
Department of Microbiology and Molecular Genetics, California College of Medicine, University of California, Irvine 92717.
Dewalt
P G
PG
Johnson
V H
VH
Lamb
J G
JG
Semler
B L
BL
D002213:Capsid / Q000378:metabolism*; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000378:metabolism*; D017955:Poliovirus / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism; D013379:Substrate Specificity
D011498:Protein Precursors; D010447:Peptide Hydrolases