A Pyranose-2-Phosphate Motif Is Responsible for Both Antibiotic Import and Quorum-Sensing Regulation in Agrobacterium tumefaciens

PLoS Pathogens

Sara Planamente¹  Denis Faure¹  Julien Lang²  Magali Aumont-Nicaise²  Solange Moréra²  Yves Queneau²  Beatriz G. Guimaraes³  John Reader³  Abbas El Sahili³  Si-Zhe Li⁴  Cornelia Virus⁴  Mohammed Ahmar⁴  Laurent Soulère⁵  Armelle Vigouroux⁶ 

[1] Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America;Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires, ICBMS, Université de Lyon, INSA Lyon, UMR 5246, CNRS, Université Lyon 1, INSA Lyon, CPE-Lyon, Bât J. Verne, Villeurbanne, France;Institute for Integrative Biology of the Cell (I2BC), Department of Biophysics, Biochemistry and Structural Biology, CNRS CEA University Paris-Sud, Gif-sur-Yvette, France;Institute for Integrative Biology of the Cell (I2BC), Department of Microbiology, CNRS CEA University Paris-Sud, Gif-sur-Yvette, France;Institute for Integrative Biology of the Cell (I2BC), Protein-Protein Interaction Platform, CNRS CEA University Paris-Sud, Orsay, France;Synchrotron SOLEIL, Gif sur Yvette, France

关键词: Agrobacterium tumefaciens;    Antibiotics;    Glucose;    Plasmids;    Agrobacteria;    Phosphates;    Sucrose;    Cytoplasm;   

DOI  :  10.1371/journal.ppat.1005071

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Periplasmic binding proteins (PBPs) in association with ABC transporters select and import a wide variety of ligands into bacterial cytoplasm. They can also take up toxic molecules, as observed in the case of the phytopathogen Agrobacterium tumefaciens strain C58. This organism contains a PBP called AccA that mediates the import of the antibiotic agrocin 84, as well as the opine agrocinopine A that acts as both a nutrient and a signalling molecule for the dissemination of virulence genes through quorum-sensing. Here, we characterized the binding mode of AccA using purified agrocin 84 and synthetic agrocinopine A by X-ray crystallography at very high resolution and performed affinity measurements. Structural and affinity analyses revealed that AccA recognizes an uncommon and specific motif, a pyranose-2-phosphate moiety which is present in both imported molecules via the L-arabinopyranose moiety in agrocinopine A and the D-glucopyranose moiety in agrocin 84. We hypothesized that AccA is a gateway allowing the import of any compound possessing a pyranose-2-phosphate motif at one end. This was structurally and functionally confirmed by experiments using four synthetic compounds: agrocinopine 3’-O-benzoate, L-arabinose-2-isopropylphosphate, L-arabinose-2-phosphate and D-glucose-2-phosphate. By combining affinity measurements and in vivo assays, we demonstrated that both L-arabinose-2-phosphate and D-glucose-2-phosphate, which are the AccF mediated degradation products of agrocinopine A and agrocin 84 respectively, interact with the master transcriptional regulator AccR and activate the quorum-sensing signal synthesis and Ti plasmid transfer in A. tumefaciens C58. Our findings shed light on the role of agrocinopine and antibiotic agrocin 84 on quorum-sensing regulation in A. tumefaciens and reveal how the PBP AccA acts as vehicle for the importation of both molecules by means of a key-recognition motif. It also opens future possibilities for the rational design of antibiotic and anti-virulence compounds against A. tumefaciens or other pathogens possessing similar PBPs.

【 授权许可】

CC BY