second cyclin box found in viral cyclin (v-cyclin)
v-Cyclin modulates host cell cycle progression and apoptotic signaling pathways. It forms an active kinase complex with cellular CDK6, a cellular cyclin-dependent kinase known to interact with cellular type D cyclins. v-Cyclin belongs to Cyclin D subfamily. It contains two cyclin boxes. This model corresponds to the second one. The cyclin box is a protein binding domain.