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Crystal structure of the periplasmic sugar binding protein ChvECrystal structure of the periplasmic sugar binding protein ChvE
Structural highlights
Function[CHVE_AGRFC] Required for effective transcriptional induction of the vir genes by monosaccharides in response to plant signals and for normal growth and chemotaxis towards certain sugars. Function as a periplasmic multiple sugar-binding receptor protein. It does not interact with a transport system. Publication Abstract from PubMedAgrobacterium tumefaciens is a broad host range plant pathogen that combinatorially recognizes diverse host molecules including phenolics, low pH, and aldose monosaccharides to activate its pathogenic pathways. Chromosomal virulence gene E (chvE) encodes a periplasmic-binding protein that binds several neutral sugars and sugar acids, and subsequently interacts with the VirA/VirG regulatory system to stimulate virulence (vir) gene expression. Here, a combination of genetics, X-ray crystallography, and isothermal calorimetry reveals how ChvE binds the different monosaccharides and also shows that binding of sugar acids is pH dependent. Moreover, the potency of a sugar for vir gene expression is modulated by a transport system that also relies on ChvE. These two circuits tune the overall system to respond to sugar concentrations encountered in vivo. Finally, using chvE mutants with restricted sugar specificities, we show that there is host variation in regard to the types of sugars that are limiting for vir induction. Agrobacterium tumefaciens recognizes its host environment using ChvE to bind diverse plant sugars as virulence signals.,Hu X, Zhao J, Degrado WF, Binns AN Proc Natl Acad Sci U S A. 2013 Jan 8;110(2):678-83. doi: 10.1073/pnas.1215033110., Epub 2012 Dec 24. PMID:23267119[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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