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Literature summary for 2.7.13.3 extracted from

  • Fang, F.; Lin, Y.H.; Pierce, B.D.; Lynn, D.G.
    A Rhizobium radiobacter histidine kinase can employ both boolean AND and OR logic gates to initiate pathogenesis (2015), ChemBioChem, 16, 2183-2190.
    View publication on PubMed

Activating Compound

Activating Compound Comment Organism Structure
2,6-dimethoxyphenol activation of VirA increases in the absence of enzyme aas 285-293 Agrobacterium tumefaciens
acetosyringone
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Agrobacterium tumefaciens
additional information small molecule inducers (phenols and sugars) are produced at a wound site and activate the enzyme to induce gene transfer processes, VirA serves as the histidine autokinase antenna that phosphorylates VirG as the active transcriptional regulator Agrobacterium tumefaciens
phenol
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Agrobacterium tumefaciens

Application

Application Comment Organism
additional information long-range signal transmission through the histidine kinase VirA can be exploited for synthetic signaling circuits Agrobacterium tumefaciens

Protein Variants

Protein Variants Comment Organism
additional information removal of the first 280 amino acids of VirA, referred to as VirA(LKR), and further removal of the charged residues VirA(LKR)D280-284, preserves basic wild-type induction in response to acetosyringone. Further truncation to VirA(LKR)D280-293 eliminates induction by acetosyringone while increasing the induction of 2,6-dimethoxyphenol, which lacks the para substituent of acetosyringone. Construction of the truncated construct VirA(LKR)D280-284, amino acid residues 285-293 are randomly mutagenized, and the resulting colonies are probed for altered specificity in a sequential phenol specificity screen Agrobacterium tumefaciens
Y293F site-directed mutagenesis, Y293F substitution in full-length VirA changes the phenol perception, mutation VirA(LKR)D280-284,Y293F does not alter phenol specificity nearly to the extent as mutant Y293T, it does increase the activity of virtually all active phenols roughly 30fold above that of VirA(LKR)D280-284. Acetosyringone sensitivity increases in VirAY293F with and without glucose Agrobacterium tumefaciens
Y293T site-directed mutagenesis, Y293T substitution in full-length VirA changes the phenol perception, mutation VirA(LKR)D280-284,Y293T alters phenol specificity of the enzyme Agrobacterium tumefaciens

Localization

Localization Comment Organism GeneOntology No. Textmining
inner membrane a transmembrane protein with a periplasmic domain Agrobacterium tumefaciens
-
-

Organism

Organism UniProt Comment Textmining
Agrobacterium tumefaciens
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formerly Agrobacterium tumefaciens
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Agrobacterium tumefaciens A136
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formerly Agrobacterium tumefaciens
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Subunits

Subunits Comment Organism
More basic architecture of VirA/VirG histidine kinase: the membrane-embedded VirA histidine kinase contains four modular domains, and the signal inputs activate the VirG response regulator. The sugar-binding protein ChvE interacts with the periplasmic domain, and phenols interact with the linker domain. The linker is predicted to adopt a GAF fold with the alpha1 helix. The conserved His474 is located in the dimerization domain of the kinase Agrobacterium tumefaciens

Synonyms

Synonyms Comment Organism
histidine autokinase
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Agrobacterium tumefaciens
VirA
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Agrobacterium tumefaciens

General Information

General Information Comment Organism
malfunction residue 293 plays a central role in the altered structural specificity of the DELTA280-293 truncation, activation of VirA by phenols increases in the absence of enzyme aas 285-293. Mutations in the L domain can rescue null mutants in the R domain. Y293F substitution switches VirA from requiring two separate inputs to an OR gate, responding to both signals separately Agrobacterium tumefaciens
additional information basic architecture of VirA/VirG histidine kinase: the membrane-embedded VirA histidine kinase contains four modular domains, and the signal inputs activate the VirG response regulator. The sugar-binding protein ChvE interacts with the periplasmic domain, and phenols interact with the linker domain. The linker is predicted to adopt a GAF fold with the alpha1 helix. The conserved His474 is located in the dimerization domain of the kinase Agrobacterium tumefaciens
physiological function Ti plasmid-encoded two-component signaling system, designated VirA and VirG, where VirA serves as the histidine autokinase antenna that phosphorylates VirG as the active transcriptional regulator. Histidine kinase VirA processes multiple small molecule host signals (phenol and sugar) and is essential for pathogenesis of Rhizobium radiobacter. A single residue can switch enzyme VirA from a functional AND logic gate to an OR gate where each of two signals activate independently. Host range preferences among natural strains of Rhizobium radiobacter correlate with these gate logic strategies. VirA, which exists in the inner membrane as a homodimer, is composed of multiple domains assigned as periplasmic (P), linker (L), kinase (K), and receiver (R). Sugar perception requires the P domain, whereas phenols require the L domain, localizing detection of these small molecules to opposite sides of the inner membrane. Importance of the integration node, specifically residue 293, as critical for signaling. In most natural isolates, including the frequently used A6 and C58 strains, the wild-type residue for 293 is tyrosine, but in strains Ag162, AB2/73, and KU12, the residue at 293 is phenylalanine. Strains A6, C58, and KU12 are wide-host-range pathogens, whereas strains Ag162 and AB2/73 show limited host ranges Agrobacterium tumefaciens