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.

The thick waxy coat of mycobacteria, a protective layer against antibiotics and the host's immune system

“…MmpL protein expression is controlled by transcriptional repressors, which are in turn regulated by the availability of fatty acids; MmpL3 is regulated by three TetR regulators: Rv3249c, Rv0302 and Rv1816, all of which dissociate from DNA upon binding palmitic acid, relieving transcriptional repression [173][174][175].…”

The crystal structure of AcrR from Mycobacterium tuberculosis reveals a one‐component transcriptional regulation mechanism

“…Additionally, structural comparison between two AcrRs from M. tuberculosis , Protein Data Bank (PDB) code http://www.rcsb.org/pdb/search/structidSearch.do?structureId=6A4W and http://www.rcsb.org/pdb/search/structidSearch.do?structureId=5D19, was conducted to further obtain structural information on M. tuberculosis AcrR . Interestingly, two conformations of AcrR with different space groups, P 6 1 (http://www.rcsb.org/pdb/search/structidSearch.do?structureId=6A4W) and P 2 1 2 1 2 1 (http://www.rcsb.org/pdb/search/structidSearch.do?structureId=5D19), have been observed.…”

“…Mycobacterium tuberculosis AcrR contains nine a-helices and two 3 10 -helices (g) in the following order: a1 (residues: [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28], a2 (residues: 37-44), a3 (residues: [48][49][50][51][52][53][54][55], a4 (residues: 58-75), g1 (residues: 80-82), a5 (residues: 91-103), a6 (residues: 107-116), a7 (residues: 123-144), g2 (residues: 145-147), a8 (residues: 154-181), and a9 (residues: 188-207; Fig. 1B).…”

“…Additionally, structural comparison between two AcrRs from M. tuberculosis, Protein Data Bank (PDB) code 6A4W and 5D19, was conducted to further obtain structural information on M. tuberculosis AcrR [22]. Interestingly, two conformations of AcrR with different space groups, P6 1 (6A4W) and P2 1 2 1 2 1 (5D19), have been observed.…”

Comparative in-silico proteomic analysis discerns potential granuloma proteins of Yersinia pseudotuberculosis

“…These proteins regulate gene expression by binding to the major grove of DNA. These proteins regulate the expression of mycobacterial membrane protein family transporters which are critical for exporting fatty acids and lipidic elements important for mycobacterial virulence 60 . Also, a high rate of lipid transport and metabolism helps in better survival in diverse environments.…”