Structural basis of transcription initiation: an RNA polymerase holoenzyme-DNA complex.

The crystal structure of Thermus aquaticus RNA polymerase holoenzyme (alpha2betabeta'omegasigmaA) complexed with a fork-junction promoter DNA fragment has been determined by fitting high-resolution x-ray structures of individual components into a 6.5-angstrom resolution map. The DNA lies across one face of the holoenzyme, completely outside the RNA polymerase active site channel.

Crystal structure of the Bacillus stearothermophilus anti-sigma factor SpoIIAB with the sporulation sigma factor sigmaF.

Cell type-specific transcription during Bacillus sporulation is established by sigmaF. SpoIIAB is an anti-sigma that binds and negatively regulates sigmaF, as well as a serine kinase that phosphorylates and inactivates the anti-anti-sigma SpoIIAA. The crystal structure of sigmaF bound to the SpoIIAB dimer in the low-affinity, ADP form has been determined at 2.

Structure of the bacterial RNA polymerase promoter specificity sigma subunit.

The sigma subunit is the key regulator of bacterial transcription. Proteolysis of Thermus aquaticus sigma(A), which occurred in situ during crystallization, reveals three domains, sigma(2), sigma(3), and sigma(4), connected by flexible linkers. Crystal structures of each domain were determined, as well as of sigma(4) complexed with -35 element DNA.

Disruption of Escherichia coli hepA, an RNA polymerase-associated protein, causes UV sensitivity.

During the development of purification procedures for Escherichia coli RNA polymerase (RNAP), we noticed the consistent co-purification of a 110-kDa polypeptide. Here, we report the identification of the 110-kDa protein as the product of the hepA gene, a member of the SNF2 family of putative helicases. We have cloned the hepA gene and overexpressed and purified the HepA protein.

Structural modules of the large subunits of RNA polymerase. Introducing archaebacterial and chloroplast split sites in the beta and beta' subunits of Escherichia coli RNA polymerase.

The beta and beta' subunits of Escherichia coli DNA-dependent RNA polymerase are highly conserved throughout eubacterial and eukaryotic kingdoms. However, in some archaebacteria and chloroplasts, the corresponding sequences are "split" into smaller polypeptides that are encoded by separate genes. To test if such split sites can be accommodated into E.