title: The crystal and solution structure of a putative transcriptional antiterminator from Mycobacterium tuberculosis.
abstract: We describe the crystal structure of Rv1626 from Mycobacterium tuberculosis at 1.48 A resolution and the corresponding solution structure determined from small angle X-ray scattering. The N-terminal domain shows structural homology to the receiver domains found in bacterial two-component systems. The C-terminal domain has high structural homology to a recently discovered RNA binding domain involved in transcriptional antitermination. The molecule in solution was found to be monomeric as it is in the crystal, but in solution it undergoes a conformational change that is triggered by changes in ionic strength. This is the first structure that links the phosphorylation cascade of the two-component systems with the antitermination event in the transcriptional machinery. Rv1626 belongs to a family of proteins, which we propose calling phosphorylation-dependent transcriptional antitermination regulators, so far only found in bacteria, and includes NasT, a protein from the assimilatory nitrate/nitrite reductase operon of Azetobacter vinelandii.
authors.affiliation: EMBL Hamburg Outstation, c/o DESY, Notkestrasse 85, Germany.
authors.forename: J Preben
authors.initials: JP
authors.lastname: Morth
authors.forename: Vicki
authors.initials: V
authors.lastname: Feng
authors.forename: L Jeanne
authors.initials: LJ
authors.lastname: Perry
authors.forename: Dmitri I
authors.initials: DI
authors.lastname: Svergun
authors.forename: Paul A
authors.initials: PA
authors.lastname: Tucker
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000737:chemistry* / Q000235:genetics; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C098639:NAST protein, Azotobacter vinelandii; D016601:RNA-Binding Proteins; D015534:Trans-Activators; C064872:antiterminator proteins, Bacteria; C069780:NarL protein, E coli