1u9l
From Proteopedia
Revision as of 19:04, 25 December 2014
Structural basis for a NusA- protein N interaction
Structural highlights
Function[NUSA_ECOLI] Participates in both transcription termination and antitermination. Involved in a variety of cellular and viral termination and antitermination processes, such as Rho-dependent transcriptional termination, intrinsic termination, and phage lambda N-mediated transcriptional antitermination. Also important for coordinating the cellular responses to DNA damage by coupling the processes of nucleotide excision repair and translesion synthesis to transcription.[1] [2] [3] [4] [5] [6] [7] [8] [9] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe 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. Structural basis for the interaction of Escherichia coli NusA with protein N of phage lambda.,Bonin I, Muhlberger R, Bourenkov GP, Huber R, Bacher A, Richter G, Wahl MC Proc Natl Acad Sci U S A. 2004 Sep 21;101(38):13762-7. Epub 2004 Sep 13. PMID:15365170[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
| ||||||||||||||||||||
