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Streptomyces coelicolor GlnR is a global regulator that controls genes involved in nitrogen metabolism. By genomic screening 10 new GlnR targets were identified, including enzymes for ammonium assimilation (glnII, gdhA), nitrite reduction (nirB), urea cleavage (ureA) and a number of biochemically uncharacterized proteins (SCO0255, SCO0888, SCO2195, SCO2400,(More)
Inheritable bacterial defence systems against phage infection and foreign DNA, termed CRISPR (clustered regularly interspaced short palindromic repeats), consist of cas protein genes and repeat arrays interspaced with sequences originating from invaders. The Cas proteins together with processed small spacer-repeat transcripts (crRNAs) cause degradation of(More)
The CRISPR (clustered regularly interspaced short palindromic repeats) immune system in prokaryotes uses small guide RNAs to neutralize invading viruses and plasmids. In Escherichia coli, immunity depends on a ribonucleoprotein complex called Cascade. Here we present the composition and low-resolution structure of Cascade and show how it recognizes(More)
Bacterial 6S RNA interacts specifically with RNA polymerase acting as transcriptional regulator. Until now, no detailed characterization of the spatial arrangement of the non-coding RNA within the three-dimensional structure of RNA polymerase has been performed. Here we present results obtained with the chemical nuclease FeBABE tethered to distinct(More)
The adaptation against foreign nucleic acids by the CRISPR-Cas system (Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated proteins) depends on the insertion of foreign nucleic acid-derived sequences into the CRISPR array as novel spacers by still unknown mechanism. We identified and characterized in Escherichia coli intermediate(More)
The nucleoid-associated protein H-NS is thought to play an essential role in the organization of bacterial chromatin in Escherichia coli. Homologues, often with very low sequence identity, are found in most gram-negative bacteria. Microscopic analysis reveals that, despite limited sequence identity, their structural organization results in similar DNA(More)
We have isolated a small Escherichia coli protein which stably interacts with ribosomal RNA P1 promoter DNA. We present evidence showing that the protein is identical to the histone-like E. coli protein, H-NS (H1). Binding of H-NS to the P1 promoter region is dependent on the DNA curvature. Mapping the H-NS-DNA contact sites by nuclease protection and(More)
The recently discovered prokaryotic CRISPR/Cas defence system provides immunity against viral infections and plasmid conjugation. It has been demonstrated that in Escherichia coli transcription of the Cascade genes (casABCDE) and to some extent the CRISPR array is repressed by heat-stable nucleoid-structuring (H-NS) protein, a global transcriptional(More)
6S RNA from E. coli is known to bind to RNA polymerase interfering with transcription initiation. Because 6S RNA concentrations are maximal at stationary phase and binding occurs preferentially to the holoenzyme associated with σ70 (Eσ70) it is believed that 6S RNA supports adjustment to stationary phase transcription. Previous studies have also suggested(More)
Transcription of stable RNA genes is known to be dramatically reduced in the presence of guanosine tetraphosphate (ppGpp), the mediator of the stringent response. Using in vitro transcription systems with ribosomal RNA P1 promoters, we have analyzed which step of the initiation cycle is inhibited by the effector ppGpp. We show that formation of the ternary(More)