1U9L

Structural basis for a NusA- protein N interaction

Summary for 1U9L

• Entry DOI: 10.2210/pdb1u9l/pdb
• Descriptor: Transcription elongation protein nusA, Lambda N, GOLD ION, ... (4 entities in total)
• Functional Keywords: escherichia coli nusa, phage lambda protein n, regulation of rna binding, transcription antitermination, rna binding protein
• Biological source: Escherichia coli; More
• Total number of polymer chains: 3
• Total formula weight: 16559.27

Authors

Bonin, I.,Muehlberger, R.,Bourenkov, G.P.,Huber, R.,Bacher, A.,Richter, G.,Wahl, M.C. (deposition date: 2004-08-10, release date: 2004-08-31, Last modification date: 2024-03-13)

Primary citation

Bonin, I.,Muehlberger, R.,Bourenkov, G.P.,Huber, R.,Bacher, A.,Richter, G.,Wahl, M.C.
Structural basis for the interaction of Escherichia coli NusA with protein N of phage lambda
Proc.Natl.Acad.Sci.Usa, 101:13762-13767, 2004

PubMed Abstract: The C terminus of transcription factor NusA from Escherichia coli comprises two repeat units, which bind during antitermination to protein N from phage lambda. To delineate the structural basis of the NusA-lambdaN interaction, we attempted to crystallize the NusA C-terminal repeats in complex with a lambdaN peptide (residues 34-47). The two NusA domains became proteolytically separated during crystallization, and crystals contained two copies of the first repeat unit in contact with a single lambdaN fragment. The NusA modules employ identical regions to contact the peptide but approach the ligand from opposite sides. In contrast to the alpha-helical conformation of the lambdaN N terminus in complex with boxB RNA, residues 34-40 of lambdaN remain extended upon interaction with NusA. Mutational analyses indicated that only one of the observed NusA-lambdaN interaction modes is biologically significant, supporting an equimolar ratio of NusA and lambdaN in antitermination complexes. Solution studies indicated that additional interactions are fostered by the second NusA repeat unit, consistent with known compensatory mutations in NusA and lambdaN. Contrary to the RNA polymerase alpha subunit, lambdaN binding does not stimulate RNA interaction of NusA. The results demonstrate that lambdaN serves as a scaffold to closely oppose NusA and the mRNA in antitermination complexes.

PubMed: 15365170
DOI: 10.1073/pnas.0405883101

Experimental method

X-RAY DIFFRACTION (1.9 Å)