NMR mapping of the HIV-1 Tat interaction surface of the KIX domain of the human coactivator CBP.

Tat is required for the expression of the HIV-1 genome. HIV-1 Tat interacts with the human transcriptional coactivator and acetyltransferase CREB-binding protein (CBP) via the KIX domain of CBP. Chemical shift perturbation mapping with nuclear magnetic resonance spectroscopy was used to identify the surface of human KIX that interacts with Tat. It was found that Tat binds to the c-Jun/MLL/Tax binding surface of KIX, as opposed to the CREB binding site. The results provide new insight into the molecular basis of the assembly of protein complexes involving p300/CBP and Tat during HIV gene expression.