title: Crystal structure of the Mycobacterium tuberculosis transcriptional regulator Rv0302.
abstract: Mycobacterium tuberculosis is a pathogenic bacterial species, which is neither Gram positive nor Gram negative. It has a unique cell wall, making it difficult to kill and conferring resistance to antibiotics that disrupt cell wall biosynthesis. Thus, the mycobacterial cell wall is critical to the virulence of these pathogens. Recent work shows that the mycobacterial membrane protein large (MmpL) family of transporters contributes to cell wall biosynthesis by exporting fatty acids and lipidic elements of the cell wall. The expression of the Mycobacterium tuberculosis MmpL proteins is controlled by a complicated regulatory network system. Here we report crystallographic structures of two forms of the TetR-family transcriptional regulator Rv0302, which participates in regulating the expression of MmpL proteins. The structures reveal a dimeric, two-domain molecule with architecture consistent with the TetR family of regulators. Comparison of the two Rv0302 crystal structures suggests that the conformational changes leading to derepression may be due to a rigid body rotational motion within the dimer interface of the regulator. Using fluorescence polarization and electrophoretic mobility shift assays, we demonstrate the recognition of promoter and intragenic regions of multiple mmpL genes by this protein. In addition, our isothermal titration calorimetry and electrophoretic mobility shift experiments indicate that fatty acids may be the natural ligand of this regulator. Taken together, these experiments provide new perspectives on the regulation of the MmpL family of transporters.
authors.affiliation: Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011.
authors.forename: Tsung-Han
authors.initials: TH
authors.lastname: Chou
authors.affiliation: Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011.
authors.forename: Jared A
authors.initials: JA
authors.lastname: Delmar
authors.affiliation: Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon, 97239.
authors.forename: Catherine C
authors.initials: CC
authors.lastname: Wright
authors.affiliation: Department of Chemistry, Iowa State University, Ames, Iowa, 50011.
authors.forename: Nitin
authors.initials: N
authors.lastname: Kumar
authors.affiliation: Department of Chemistry, Iowa State University, Ames, Iowa, 50011.
authors.forename: Abhijith
authors.initials: A
authors.lastname: Radhakrishnan
authors.affiliation: Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon, 97239.
authors.forename: Julia K
authors.initials: JK
authors.lastname: Doh
authors.affiliation: Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon, 97239.
authors.forename: Meredith H
authors.initials: MH
authors.lastname: Licon
authors.affiliation: Department of Chemistry, Iowa State University, Ames, Iowa, 50011.
authors.forename: Jani Reddy
authors.initials: JR
authors.lastname: Bolla
authors.affiliation: Department of Chemistry, Iowa State University, Ames, Iowa, 50011.
authors.forename: Hsiang-Ting
authors.initials: HT
authors.lastname: Lei
authors.affiliation: NE-CAT and Department of Chemistry and Chemical Biology, Argonne National Laboratory, Cornell University, Argonne, Illinois, 60439.
authors.forename: Kanagalaghatta R
authors.initials: KR
authors.lastname: Rajashankar
authors.affiliation: Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011.
authors.forename: Chih-Chia
authors.initials: CC
authors.lastname: Su
authors.affiliation: Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon, 97239.
authors.forename: Georgiana E
authors.initials: GE
authors.lastname: Purdy
authors.affiliation: Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011.|Department of Chemistry, Iowa State University, Ames, Iowa, 50011.
authors.forename: Edward W
authors.initials: EW
authors.lastname: Yu
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray; D005227:Fatty Acids / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D008958:Models, Molecular; D009169:Mycobacterium tuberculosis / Q000737:chemistry / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
chemical_list: D001426:Bacterial Proteins; D005227:Fatty Acids; D026901:Membrane Transport Proteins
keywords: Mycobacterial membrane protein; Mycobacterial membrane protein large; Rv0302; TetR-family regulator; small