Expression in Escherichia coli: production and purification of both subunits of the human general transcription factor TFIIE.

Both subunits of the human class II transcription factor TFIIE (rTFIIE alpha and rTFIIE beta) have been overexpressed in Escherichia coli at 26 degrees C using a T7 RNA polymerase expression system and further purified to apparent homogeneity. As in this system rTFIIE alpha was poorly expressed and copurified with a truncated form, we expressed rTFIIE alpha as a fusion protein. These overexpressed subunits of TFIIE are similar to the endogenous subunits according to the following criteria: molecular weight, microsequencing, and transcription activity.