1. Structural basis of a novel repressor, SghR, controlling Agrobacterium infection by cross-talking to plants
- Author
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Qinqin Fu, Fuzhou Ye, Haiwei Song, Xin-Fu Yan, Lian-Hui Zhang, Sakshibeedu R. Bharath, Arnau Casanas, Meitian Wang, Chao Wang, and Yong-Gui Gao
- Subjects
0301 basic medicine ,Operator (biology) ,Rhizobiaceae ,030102 biochemistry & molecular biology ,Agrobacterium ,Repressor ,Virulence ,Promoter ,Cell Biology ,Agrobacterium tumefaciens ,Biology ,Response Elements ,biology.organism_classification ,Biochemistry ,Cell biology ,03 medical and health sciences ,030104 developmental biology ,Bacterial Proteins ,Plant Tumors ,Protein Structure and Folding ,Molecular Biology ,Transcription factor ,Signal Transduction - Abstract
Agrobacterium tumefaciens infects various plants and causes crown gall diseases involving temporal expression of virulence factors. SghA is a newly identified virulence factor enzymatically releasing salicylic acid from its glucoside conjugate and controlling plant tumor development. Here, we report the structural basis of SghR, a LacI-type transcription factor highly conserved in Rhizobiaceae family, regulating the expression of SghA and involved in tumorigenesis. We identified and characterized the binding site of SghR on the promoter region of sghA and then determined the crystal structures of apo-SghR, SghR complexed with its operator DNA, and ligand sucrose, respectively. These results provide detailed insights into how SghR recognizes its cognate DNA and shed a mechanistic light on how sucrose attenuates the affinity of SghR with DNA to modulate the expression of SghA. Given the important role of SghR in mediating the signaling cross-talk during Agrobacterium infection, our results pave the way for structure-based inducer analog design, which has potential applications for agricultural industry.
- Published
- 2020