Capsid Protein, PCV (Cap)

The capsid protein (Cap) is the sole structural protein and the main antigen of porcine circovirus .

The capsid protein encoded by the open reading frame 2 (ORF2) of PCV is capable of self-assembly into VLP and resembling the icosahedral morphology of the native PCV virions. Cap is necessary for virion packaging and may participate in genome replication by interacting with Rep protein and is also the main viral immunogen and acts as a key regulator of viral replication as well as the virus-host interaction. It is reported that the carboxyl terminus (CT) of the PCV Cap is known to play critical roles in the evolution, pathogenesis, and proliferation of this virus, while the molecular mechanisms are yet unknown at present. The carboxyl terminus (CT) of capsid protein (Cap) was previously reported to be associated with immunorecognition, alterations of viral titer in swine sera, and pathogenicity.