title: Structural characterization of the multidomain regulatory protein Rv1364c from Mycobacterium tuberculosis.
abstract: The open reading frame rv1364c of Mycobacterium tuberculosis, which regulates the stress-dependent σ factor, σ(F), has been analyzed structurally and functionally. Rv1364c contains domains with sequence similarity to the RsbP/RsbW/RsbV regulatory system of the stress-response σ factor of Bacillus subtilis. Rv1364c contains, sequentially, a PAS domain (which shows sequence similarity to the PAS domain of the B. subtilis RsbP protein), an active phosphatase domain, a kinase (anti-σ(F) like) domain and a C-terminal anti-σ(F) antagonist like domain. The crystal structures of two PAS domain constructs (at 2.3 and 1.6 Å) and a phosphatase/kinase dual domain construct (at 2.6 Å) are described. The PAS domain is shown to bind palmitic acid but to have 100 times greater affinity for palmitoleic acid. The full-length protein can exist in solution as both monomer and dimer. We speculate that a switch between monomer and dimer, possibly resulting from fatty acid binding, affects the accessibility of the serine of the C-terminal, anti-σ(F) antagonist domain for dephosphorylation by the phosphatase domain thus indirectly altering the availability of σ(F).
authors.affiliation: EMBL Hamburg Outstation, c/o DESY, Notkestrasse 85, D22603, Hamburg, Germany.
authors.forename: Jack
authors.initials: J
authors.lastname: King-Scott
authors.forename: Petr V
authors.initials: PV
authors.lastname: Konarev
authors.forename: Santosh
authors.initials: S
authors.lastname: Panjikar
authors.forename: Rositsa
authors.initials: R
authors.lastname: Jordanova
authors.forename: Dmitri I
authors.initials: DI
authors.lastname: Svergun
authors.forename: Paul A
authors.initials: PA
authors.lastname: Tucker
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D057075:Enzyme Assays; D005227:Fatty Acids / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D010770:Phosphotransferases / Q000737:chemistry*; D011485:Protein Binding; D055503:Protein Multimerization; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D053838:Scattering, Small Angle; D040681:Structural Homology, Protein; D014961:X-Ray Diffraction
chemical_list: D001426:Bacterial Proteins; D005227:Fatty Acids; D010770:Phosphotransferases; C116037:PAS domain kinases; D017346:Protein Serine-Threonine Kinases