Home About us Contact
|
Home About us Contact | ||
|
|
||
Bacterial RNA Polymerase (bacterial + rna_polymerase)
Selected AbstractsStructure of Microcin J25, a Peptide Inhibitor of Bacterial RNA Polymerase, is a Lassoed Tail.CHEMINFORM, Issue 4 2004Kelly-Anne Wilson No abstract is available for this article. [source] Mechanisms for activating bacterial RNA polymeraseFEMS MICROBIOLOGY REVIEWS, Issue 5 2010Tamaswati Ghosh Abstract Gene transcription is a fundamental cellular process carried out by RNA polymerase (RNAP) enzymes and is highly regulated through the action of gene regulatory complexes. Important mechanistic insights have been gained from structural studies on multisubunit RNAP from bacteria, yeast and archaea, although the initiation process that involves the conversion of the inactive transcription complex to an active one has yet to be fully understood. RNAPs are unambiguously closely related in structure and function across all kingdoms of life and have conserved mechanisms. In bacteria, sigma (,) factors direct RNAP to specific promoter sites and the RNAP/, holoenzyme can either form a stable closed complex that is incompetent for transcription (as in the case of ,54) or can spontaneously proceed to an open complex that is competent for transcription (as in the case of ,70). The conversion of the RNAP/,54 closed complex to an open complex requires ATP hydrolysis by enhancer-binding proteins, hence providing an ideal model system for studying the initiation process biochemically and structurally. In this review, we present recent structural studies of the two major bacterial RNAP holoenzymes and focus on mechanistic advances in the transcription initiation process via enhancer-binding proteins. [source] Modus operandi of the bacterial RNA polymerase containing the ,54 promoter-specificity factorMOLECULAR MICROBIOLOGY, Issue 3 2008Sivaramesh Wigneshweraraj Summary Bacterial sigma (,) factors confer gene specificity upon the RNA polymerase, the central enzyme that catalyses gene transcription. The binding of the alternative , factor ,54 confers upon the RNA polymerase special functional and regulatory properties, making it suited for control of several major adaptive responses. Here, we summarize our current understanding of the interactions the ,54 factor makes with the bacterial transcription machinery. [source] Mechanochemical ATPases and transcriptional activationMOLECULAR MICROBIOLOGY, Issue 4 2002X. Zhang Summary Transcriptional activator proteins that act upon the ,54 -containing form of the bacterial RNA polymerase belong to the extensive AAA+ superfamily of ATPases, members of which are found in all three kingdoms of life and function in diverse cellular processes, often via chaperone-like activities. Formation and collapse of the transition state of ATP for hydrolysis appears to engender the interaction of the activator proteins with ,54 and leads to the protein structural transitions needed for RNA polymerase to isomerize and engage with the DNA template strand. The common oligomeric structures of AAA+ proteins and the crea-tion of the active site for ATP hydrolysis between protomers suggest that the critical changes in protomer structure required for productive interactions with ,54 -holoenzyme occur as a consequence of sensing the state of the , -phosphate of ATP. Depending upon the form of nucleotide bound, different functional states of the activator are created that have distinct substrate and chaperone-like binding activ-ities. In particular, interprotomer ATP interactions rely upon the use of an arginine finger, a situation reminiscent of GTPase-activating proteins. [source] UPs and downs in bacterial transcription initiation: the role of the alpha subunit of RNA polymerase in promoter recognitionMOLECULAR MICROBIOLOGY, Issue 4 2000Richard L. Gourse In recent years, it has become clear that promoter recognition by bacterial RNA polymerase involves interactions not only between core promoter elements and the , subunit, but also between a DNA element upstream of the core promoter and the , subunit. DNA binding by , can increase transcription dramatically. Here we review the current state of our understanding of the , interaction with DNA during basal transcription initiation (i.e. in the absence of proteins other than RNA polymerase) and activated transcription initiation (i.e. when stimulated by transcription factors). [source] | ||||||||||