The E. coli NusA carboxy-terminal domains are structurally similar and show specific RNAP- and lambdaN interaction.
The carboxy-terminal domain of the transcription factor Escherichia coli NusA, NusACTD, interacts with the protein N of bacteriophage lambda, lambdaN, and the carboxyl terminus of the E. coli RNA polymerase alpha subunit, alphaCTD. We solved the solution structure of the unbound NusACTD with high-resolution nuclear magnetic resonance (NMR). Additionally, we investigated the binding sites of lambdaN and alphaCTD on NusACTD using NMR titrations. The solution structure of NusACTD shows two structurally similar subdomains, NusA(353-416) and NusA(431-490), matching approximately two homologous acidic sequence repeats. Further characterization of NusACTD with 15N NMR relaxation data suggests that the interdomain region is only weakly structured and that the subdomains are not interacting. Both subdomains adopt an (HhH)2 fold. These folds are normally involved in DNA-protein and protein-protein interactions. NMR titration experiments show clear differences of the interactions of these two domains with alphaCTD and lambdaN, in spite of their structural similarity.
Department of Biopolymers, University of Bayreuth, 95440 Bayreuth, Germany.
Anke
A
Eisenmann
Sabine
S
Schwarz
Stefan
S
Prasch
Kristian
K
Schweimer
Paul
P
Rösch
D000595:Amino Acid Sequence; D001665:Binding Sites; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry*; D029968:Escherichia coli Proteins / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010445:Peptide Elongation Factors / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D012399:Rotation; D014157:Transcription Factors / Q000737:chemistry*; D035602:Transcriptional Elongation Factors; D054334:Viral Regulatory and Accessory Proteins / Q000737:chemistry*
D029968:Escherichia coli Proteins; C059417:N protein, Bacteriophage lambda; D010445:Peptide Elongation Factors; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; D054334:Viral Regulatory and Accessory Proteins; C068727:nusA protein, E coli; D012321:DNA-Directed RNA Polymerases; C113275:RNA polymerase alpha subunit