Immunoaffinity Purification of the Human Multisubunit Transcription Factor IIH

A procedure to immunoaffinity purify the human transcription factor IIH (TFIIH) was developed using a monoclonal antibody that recognizes an epitope in ERCC3 (XPB), the largest subunit of TFIIH. The epitope recognized by the monoclonal antibody was mapped to 20 amino acids. A peptide containing the epitope was capable of displacing TFIIH from an immunoaffinity column containing the monoclonal antibody. The immunoaffinity purification procedure described allows a simple and efficient method to purify both the "core" and "holo" TFIIH complexes.