- Zhang Y, Feng Y, Chatterjee S, Tuske S, Ho MX, Arnold E, Ebright RH
- Structural Basis of Transcription Initiation.
- Science. 2012 Oct 18.
- During transcription initiation, RNA polymerase (RNAP) binds and unwinds promoter DNA to form an RNAP-promoter open complex. We have determined crystal structures at 2.9 and 3.0 A resolution of functional transcription initiation complexes comprising Thermus thermophilus RNA polymerase, sigma(A), and a promoter DNA fragment corresponding to the transcription bubble and downstream dsDNA of the RNAP-promoter open complex. The structures show that sigma recognizes the -10 element and discriminator element through interactions that include the unstacking and insertion into pockets of three DNA bases, and that RNAP recognizes the -4/+2 region through interactions that include the unstacking and insertion into a pocket of the +2 base. The structures further show that interactions between sigma and template-strand ssDNA preorganize template-strand ssDNA to engage the RNAP active center.