Retroviral integrase protein and intasome nucleoprotein complex structures

Figure 1 Integrase catalytic functions and intasome complexes. A multimer of integrase (IN) (depicted simply by blue oval) engages the end regions of the linear vDNA molecule (yellow), forming the stable synaptic complex (SSC). During 3’-processing, IN hydrolyzes the vDNA ends adjacent to invariant CA dinucleotides, revealing a set of reactive 3’-hydroxyl groups in the confines of the cleaved donor complex (CDC). After nuclear localization, the target capture complex (TCC) is formed upon tDNA (black) capture. Strand transfer, whereby IN employs the 3’ hydroxyl groups as nucleophiles to attack the tDNA, marks the transition to the strand transfer complex (STC).