title: Role of a PAS sensor domain in the Mycobacterium tuberculosis transcription regulator Rv1364c.
abstract: The Mycobacterium tuberculosis transcriptional regulator Rv1364c regulates the activity of the stress response sigma factor sigma(F). This multi-domain protein has several components: a signaling PAS domain and an effector segment comprising of a phosphatase, a kinase and an anti-anti-sigma factor domain. Based on Small Angle X-ray Scattering (SAXS) data, Rv1364c was recently shown to be a homo-dimer and adopt an elongated conformation in solution. The PAS domain could not be modeled into the structural envelope due to poor sequence similarity with known PAS proteins. The crystal structure of the PAS domain described here provides a structural basis for the dimerization of Rv1364c. It thus appears likely that the PAS domain regulates the anti-sigma activity of Rv1364c by oligomerization. A structural comparison with other characterized PAS domains reveal several sequence and conformational features that could facilitate ligand binding - a feature which suggests that the function of Rv1364c could potentially be governed by specific cellular signals or metabolic cues.
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Ravi Kumar
authors.initials: RK
authors.lastname: Jaiswal
authors.forename: G
authors.initials: G
authors.lastname: Manjeera
authors.forename: B
authors.initials: B
authors.lastname: Gopal
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism*; D055503:Protein Multimerization; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D053838:Scattering, Small Angle; D012808:Sigma Factor / Q000737:chemistry / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism
chemical_list: D012808:Sigma Factor; D014157:Transcription Factors; C116037:PAS domain kinases; D017346:Protein Serine-Threonine Kinases