A Novel Co-Crystal Structure Affords the Design of Gain-of-Function Lentiviral Integrase Mutants in the Presence of Modified PSIP1/LEDGF/p75 - Hare, S; Shun, M-C; Gupta, SS; Valkov, E; Engelman, A; Cherepanov, P (PLOS PATHOGENS, 2009)