Description
The transcription factor IIF (TFIIF) is composed of 58 kDa (RAP74) and 26 kDa (RAP30) subunits as a heterodimer, and was first identified through the ability to interact with immobilized RNA Polymerase II. The RAP30 subunit of TFIIF contains two distinct regions with sequence similarity to E. coli factors and can deliver RNA- Polymerase II to the promoter to support transcription initiation in the absence of RAP74. Recombinant RAP30 protein is isolated from anE. colistrain that carries the coding sequence of human RAP74, the 58 kDa subunit of TFIIF under the control of T7 promoter. RAP30 can interact with RNA Polymerase II, with TFIIB, and with DNA. Protein is greater than 95% homogeneous and contains no detectable protease, DNase, and RNase activity