Studies on the disassembly of cowpea chlorotic mottle virus
The mechanism of the spherical virus disassembly has been under investigation for understanding the early events during virus infection, and eventually for helping to design reagents to block the process for releasing genetic information into host cells, thus preventing viral infection. The virus has to be stable enough to protect the genetic materials inside the virion, yet dynamic enough to release the nucleic acids to establish infection. Cowpea chlorotic mottle virus provides genetic and biochemical advantages for this purpose. The role of virus swelling for disassembly was studied based on characterization of a salt stable mutant of CCMV in vivo and in vitro. The salt stable mutant is as infectious as the wild type, swells like the wild type but shows negative signal for translation, thus swelling is not required for CCMV disassembly. The N-terminus of the coat protein on the virion is not ordered under X-ray crystallography, it is proposed to be involved in the virus disassembly. Biochemical and immunological analysis of the N-terminus shows that the N-terminus is dynamic, undergoes structural transition to the exterior of the virion presumably to form a channel on the five-fold axis during disassembly. This work will lead more biochemical studies in detail on CCMV disassembly process.