Structural insights into the functional divergence of WhiB-like proteins in Mycobacterium tuberculosis

A Feedback Regulatory Loop Containing McdR and WhiB2 Controls Cell Division and DNA Repair in Mycobacteria

“…Furthermore, we showed that WhiB2 regulates the expression of mcdR through a feedback mechanism by binding to the cGACACGc motif located upstream of the −10 promoter element ( Fig. 5 ), which is consistent with the recently characterized model proposed for the mode of action of the WhiB family of proteins ( 38 , 39 ). Interestingly, the cGACACGc motif was also found in the promoters of several other genes, including ftsBHW , plcA , clpX , and Rv1405c ( Table S4 , Fig.…”

Structural basis of DNA binding by the WhiB-like transcription factor WhiB3 in Mycobacterium tuberculosis

“…As described in the previous studies, a chimeric protein denoted σ A 4 -β tip was used for the crystallographic characterization of the σ A 4 -bound WhiB3 by fusing σ A 4 with the RNAP β-subunit flap tip helix (β tip ) via an artificial linker to mimic the interaction between σ A and the β subunit in the RNAP holoenzyme (see Experimental procedures ) ( 26 , 30 , 31 ). We also generated a truncated WhiB3, denoted WhiB3TR, without the C-terminal residues (aa 91–102) containing the putative DNA binding motif to improve the protein stability and crystallizability.…”

“…Analysis of the 3D structures reveals the structural basis for how WhiB7 binding to the AT-rich region opens the minor groove, reversely bends the DNA in the direction opposite to the expected intrinsic bending of A-track DNAs, and orchestrates with σ A for transcriptional regulation. Together, these studies provide an atomic view of how WhiB7 activates gene expression by coordinating DNA binding with σ A 4 via its AT-hook and unravel the WhiB7 subclass-specific structural features that enable WhiB7 to function differently from WhiB1 ( 26 , 27 ).…”

“…Together with the molecular and biochemical analyses, these studies reveal an unexpected molecular interface in the WhiB1:σ A 4 complex dominated by hydrophobic interactions and support a new molecular mechanism of transcription regulation by WhiB1 in Actinobacteria ( 25 ). Subsequently, the crystal structure of WhiB7 in complex with σ A 4 and its own promoter ( P whiB7 ) and the single-particle cryo-electron microscopy (cryo-EM) structure of WhiB7 bond to σ A in RNAP and P whiB7 were reported by our group and by the Campbell group, respectively ( 26 , 27 ). The WhiB7 AT-hook binding site has the characteristics of A-track DNA ( i.e.…”

Resistance and tolerance of Mycobacterium tuberculosis to antimicrobial agents—How M. tuberculosis can escape antibiotics

“…This acts on the proliferation of various cells and various adaptive regulations, including drug therapy. Studies have shown that the absence of WhiB7 can lead to high sensitivity to drugs in vitro, which may be achieved by upregulating the drug efflux pump and strengthening the interaction with upstream promoter elements (Morris et al, 2005;Wan et al, 2021). In addition, the Sig, as a replaceable small subunit of RNA polymerase, is widely expressed in all bacterial genomes, is responsible for the transcription of housekeeping genes, and can make rapid transcriptional modifications to specific stimuli (Manganelli, 2014).…”