RNA-dependent cleavage of VP0 capsid protein in provirions of hepatitis A virus.
Stable provirions of hepatitis A virus containing up to 62% VP0 were purified from infected BS-C-1 cells by sucrose density gradient ultracentrifugation, and conversion of these provirions to virions through maturation cleavage of VP0 capsid protein was demonstrated. VP0 cleavage was slow but linear over 7 days at 37 degrees, with mature virions containing between 3 and 7 copies of VP0 in separate experiments. Cleavage of approximately 25% of VP0 molecules (15 copies) was accompanied by a twofold increase in specific infectivity. Particles with reduced levels of VP0 were observed to sediment more rapidly in sucrose than VP0-rich provirions, reflecting conformational changes in the particles. The kinetics and temperature-dependence of VP0 cleavage further suggest that such conformational changes accompanying VP0 cleavage are necessary for the formation of subsequent catalytic sites.
Bishop
N E
NE
Hepatitis Research Unit, Macfarlane Burnet Centre for Medical Research, Fairfield, Victoria, Australia.
Anderson
D A
DA
D000818:Animals; D002213:Capsid / Q000096:biosynthesis / Q000378:metabolism*; D036022:Capsid Proteins; D002478:Cells, Cultured; D006507:Hepatovirus / Q000187:drug effects / Q000378:metabolism* / Q000472:pathogenicity; D006358:Hot Temperature; D011487:Protein Conformation; D011498:Protein Precursors / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D011533:Proviruses / Q000187:drug effects / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism*; D012259:Ribonuclease, Pancreatic / Q000494:pharmacology; D014774:Virulence
D036022:Capsid Proteins; D011498:Protein Precursors; D012367:RNA, Viral; C060339:VP4 protein, Rotavirus; D012259:Ribonuclease, Pancreatic