title: Regulation of signaling directionality revealed by 3D snapshots of a kinase:regulator complex in action.
abstract: Two-component systems (TCS) are protein machineries that enable cells to respond to input signals. Histidine kinases (HK) are the sensory component, transferring information toward downstream response regulators (RR). HKs transfer phosphoryl groups to their specific RRs, but also dephosphorylate them, overall ensuring proper signaling. The mechanisms by which HKs discriminate between such disparate directions, are yet unknown. We now disclose crystal structures of the HK:RR complex DesK:DesR fromBacillus subtilis, comprising snapshots of the phosphotransfer and the dephosphorylation reactions. The HK dictates the reactional outcome through conformational rearrangements that include the reactive histidine. The phosphotransfer center is asymmetric, poised for dissociative nucleophilic substitution. The structural bases of HK phosphatase/phosphotransferase control are uncovered, and the unexpected discovery of a dissociative reactional center, sheds light on the evolution of TCS phosphotransfer reversibility. Our findings should be applicable to a broad range of signaling systems and instrumental in synthetic TCS rewiring.
authors.affiliation: Laboratory of Molecular and Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay.
authors.forename: Felipe
authors.initials: F
authors.lastname: Trajtenberg
authors.affiliation: Laboratory of Molecular and Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay.
authors.forename: Juan A
authors.initials: JA
authors.lastname: Imelio
authors.affiliation: Biomolecular Simulations, Institut Pasteur de Montevideo, Montevideo, Uruguay.
authors.forename: Matías R
authors.initials: MR
authors.lastname: Machado
authors.affiliation: Laboratory of Molecular and Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay.
authors.forename: Nicole
authors.initials: N
authors.lastname: Larrieux
authors.affiliation: Departamento de Química Biológica e IQUIBICEN-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Marcelo A
authors.initials: MA
authors.lastname: Marti
authors.affiliation: Protein Biophysics Unit, Institut Pasteur de Montevideo, Montevideo, Uruguay.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Obal
authors.affiliation: Laboratory of Molecular and Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay.
authors.forename: Ariel E
authors.initials: AE
authors.lastname: Mechaly
authors.affiliation: Laboratory of Molecular and Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay.|Département de Microbiologie, Institut Pasteur, Paris, France.
authors.forename: Alejandro
authors.identifier: 0000-0002-2509-6526
authors.initials: A
authors.lastname: Buschiazzo
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology*; D018360:Crystallography, X-Ray; D000071677:Histidine Kinase / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D010766:Phosphorylation; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D015398:Signal Transduction; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D014157:Transcription Factors; D000071677:Histidine Kinase
keywords: B. subtilis; E. coli; allosteric control of protein function; biophysics; cell signaling; infectious disease; microbiology; phosphoryl-transfer mechanism; structural biology; two component systems