Chlorellavirus CVK2 particles contain several capsid proteins that are selectively released by treatment with 4Murea. Seven of them (Vp52, Vp45, Vp41, Vp25, Vp20.5, Vp20, and Vp16.2) have been identified based on amino acid sequences at the N-terminus. Comparison of the amino acid sequences with the corresponding ORFs deduced from the nucleotide sequence of PBCV-1, the prototype member ofPhycodnaviridae,revealed that the CVK2 proteins were processed at the N-terminal region by two different proteolytic activities.