T7 promoter release mediated by DNA scrunching

Evidence for DNA bending at the T7 RNA polymerase promoter.

Phage T7 RNA polymerase is the only DNA-dependent RNA polymerase for which we have a high-resolution structure of the promoter-bound complex. Recent studies with the more complex RNA polymerases have suggested a role for DNA wrapping in the initiation of transcription. Here, circular permutation gel retardation assays provide evidence that the polymerase does indeed bend its promoter DNA. A com...

Transcription initiation in a single-subunit RNA polymerase proceeds through DNA scrunching and rotation of the N-terminal subdomains.

Elucidating the mechanism of transcription initiation by RNA polymerases (RNAP) is essential for understanding gene transcription and regulation. Although several models, such as DNA scrunching, RNAP translation, and RNAP rotation, have been proposed, the mechanism of initiation by T7 RNAP has remained unclear. Using ensemble and single-molecule Förster resonance energy transfer (FRET) studies,...

Structure and function in promoter escape by T7 RNA polymerase.

Digestion of damaged DNA by the T7 DNA polymerase-exonuclease.

We have investigated the 3'-5'-exonuclease activity of phage T7 DNA polymerase for its usefulness as an approach for the detection of lesions in DNA. Unlike the T4 DNA polymerase-exonuclease, which is commonly used to map the position and frequency of lesions in very small DNA fragments, T7 DNA polymerase-exonuclease is able to hydrolyse almost completely the large fragments from KpnI-restricte...

Promoter specificity determinants of T7 RNA polymerase.

The high specificity of T7 RNA polymerase (RNAP) for its promoter sequence is mediated, in part, by a specificity loop (residues 742-773) that projects into the DNA binding cleft (1). Previous work demonstrated a role for the amino acid residue at position 748 (N748) in this loop in discrimination of the base pairs (bp) at positions -10 and -11 (2). A comparison of the sequences of other phage ...