This domain is found in viruses, and is about 30 amino acids in length. It is found in association with pfam02232. This domain is the C terminal of the HSV virion protein 16. This protein is a transcription promoter. The C terminal domain is the carboxyl subdomain of the acidic transcriptional activation domain. The protein binds to DNA binding proteins to carry out its function. Such proteins include TATA binding protein, CBP, TBP-binding protein, etc.