Activating region of HIV-1 Tat protein: vacuum UV circular dichroism and energy minimization.

Tat protein is a trans-acting transcriptional activator of the human immunodeficiency virus type 1 and is essential for viral transcription. By homology with other transcriptional activators, Tat is expected to possess a nucleic acid binding region and a separate adjacent activating region. In order to localize the activating region of Tat, we have synthesized the sequences 2-23 and 38-60 of the protein