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Structural basis of a novel repressor SghR controlling Agrobacterium infection by cross-talking to plants

DOI: 10.1074/jbc.RA120.012908 DOI Help

Authors: Fuzhou Ye (Nanyang Technological University) , Chao Wang (South China Agricultural University) , Qinqin Fu (Nanyang Technological University) , Xin-fu Yan (Nanyang Technological University) , Sakshibeedu R. Bharath , Arnau Casanas (Paul Scherrer Institute) , Meitian Wang (Swiss Light Source) , Haiwei Song (Institute of Molecular and Cell Biology) , Lian-hui Zhang (South China Agricultural University) , Yong-gui Gao (Nanyang Technological University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Biological Chemistry

State: Published (Approved)
Published: July 2020

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 the plant tumor development. Here we report the structural basis of SghR, a LacI-type transcription factor and 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 crosstalk during Agrobacterium infection, our results pave the way for structure-based inducer analogue design, which has potential applications for agricultural industry.

Journal Keywords: SghR; LacI family; Salicylic acid; Sucrose; gene regulation; inhibition mechanism; microbial pathogenesis; host-pathogen interaction; crystal structure

Subject Areas: Biology and Bio-materials, Chemistry

Instruments: I04-Macromolecular Crystallography

Other Facilities: X06SA at Swiss Light Source