scholarly journals Sensor Domains Encoded in Bacillus anthracis Virulence Plasmids Prevent Sporulation by Hijacking a Sporulation Sensor Histidine Kinase

2006 ◽  
Vol 188 (17) ◽  
pp. 6354-6360 ◽  
Author(s):  
Andrea K. White ◽  
James A. Hoch ◽  
Marcin Grynberg ◽  
Adam Godzik ◽  
Marta Perego
Keyword(s):  
Bacillus Anthracis ◽  
Histidine Kinase ◽  
Virulence Plasmid ◽  
Sensor Kinase ◽  
Sensor Histidine Kinase ◽  
Virulence Plasmids ◽  
Salient Characteristic ◽  
Successful Infection ◽  
Dependent Inhibition ◽  
Native Host

ABSTRACT Anthrax toxin and capsule, determinants for successful infection by Bacillus anthracis, are encoded on the virulence plasmids pXO1 and pXO2, respectively. Each of these plasmids also encodes proteins that are highly homologous to the signal sensor domain of a chromosomally encoded major sporulation sensor histidine kinase (BA2291) in this organism. B. anthracis Sterne overexpressing the plasmid pXO2-61-encoded signal sensor domain exhibited a significant decrease in sporulation that was suppressed by the deletion of the BA2291 gene. Expression of the sensor domains from the pXO1-118 and pXO2-61 genes in Bacillus subtilis strains carrying the B. anthracis sporulation sensor kinase BA2291 gene resulted in BA2291-dependent inhibition of sporulation. These results indicate that sporulation sensor kinase BA2291 is converted from an activator to an inhibitor of sporulation in its native host by the virulence plasmid-encoded signal sensor domains. We speculate that activation of these signal sensor domains contributes to the initiation of B. anthracis sporulation in the bloodstream of its infected host, a salient characteristic in the virulence of this organism, and provides an additional role for the virulence plasmids in anthrax pathogenesis.

scholarly journals A Unique GTP-Dependent Sporulation Sensor Histidine Kinase in Bacillus anthracis

2008 ◽  
Vol 191 (3) ◽  
pp. 687-692 ◽  
Author(s):  
Francesca Scaramozzino ◽  
Andrea White ◽  
Marta Perego ◽  
James A. Hoch
Keyword(s):  
Bacillus Anthracis ◽  
Histidine Kinase ◽  
Catalytic Domain ◽  
Coiled Coil ◽  
Reverse Reaction ◽  
Forward Reaction ◽  
Critical Signal ◽  
Sensor Histidine Kinase ◽  
Virulence Plasmids ◽  
Kinase Catalytic Domain

ABSTRACT The Bacillus anthracis BA2291 gene codes for a sensor histidine kinase involved in the induction of sporulation. Genes for orthologs of the sensor domain of the BA2291 kinase exist in virulence plasmids in this organism, and these proteins, when expressed, inhibit sporulation by converting BA2291 to an apparent phosphatase of the sporulation phosphorelay. Evidence suggests that the sensor domains inhibit BA2291 by titrating its activating signal ligand. Studies with purified BA2291 revealed that this kinase is uniquely specific for GTP in the forward reaction and GDP in the reverse reaction. The G1 motif of BA2291 is highly modified from ATP-specific histidine kinases, and modeling this motif in the structure of the kinase catalytic domain suggested how guanine binds to the region. A mutation in the putative coiled-coil linker between the sensor domain and the catalytic domains was found to decrease the rate of the forward autophosphorylation reaction and not affect the reverse reaction from phosphorylated Spo0F. The results suggest that the activating ligand for BA2291 is a critical signal for sporulation and in a limited concentration in the cell. Decreasing the response to it either by slowing the forward reaction through mutation or by titration of the ligand by expressing the plasmid-encoded sensor domains switches BA2291 from an inducer to an inhibitor of the phosphorelay and sporulation.

scholarly journals atxA Controls Bacillus anthracis Capsule Synthesis via acpA and a Newly Discovered Regulator, acpB

2004 ◽  
Vol 186 (2) ◽  
pp. 307-315 ◽  
Author(s):  
Melissa Drysdale ◽  
Agathe Bourgogne ◽  
Susan G. Hilsenbeck ◽  
Theresa M. Koehler
Keyword(s):  
Gene Expression ◽  
Bacillus Anthracis ◽  
Gene Transcription ◽  
Double Mutant ◽  
Regulatory Proteins ◽  
Toxin Gene ◽  
Virulence Plasmid ◽  
Predicted Amino Acid Sequence ◽  
Null Mutant ◽  
Virulence Plasmids

ABSTRACT Two regulatory genes, acpA and atxA, have been reported to control expression of the Bacillus anthracis capsule biosynthesis operon capBCAD. The atxA gene is located on the virulence plasmid pXO1, while pXO2 carries acpA and the cap genes. acpA has been viewed as the major regulator of the cap operon because it is essential for capsule gene expression in a pXO1− pXO2+ strain. atxA is essential for toxin gene transcription but has also been implicated in control of the cap genes. The molecular functions of the regulatory proteins are unknown. We examined cap gene expression in a genetically complete pXO1+ pXO2+ strain. Our results indicate that another pXO2 gene, acpB (previously called pXO2-53; accession no. NC002146.1 :49418-50866), has a role in cap expression. The predicted amino acid sequence of AcpB is 62% similar to that of AcpA and 50% similar to that of AtxA. Assessment of cap gene transcription revealed that cap expression was not affected in a pXO1+ pXO2+ acpB-null mutant and was slightly reduced in an isogenic acpA mutant. However, cap gene expression was abolished in an acpA acpB double mutant. Microscopic examination of capsule synthesis by the mutants corroborated these findings. acpA and acpB expression is controlled by atxA; capsule synthesis and transcription of acpA and acpB were markedly reduced in an atxA mutant. The data suggest that, in a strain containing both virulence plasmids, atxA is the major regulator of capsule synthesis and controls capBCAD expression indirectly, via positive regulation of acpA and acpB.

scholarly journals Novel Family of Sensor Histidine Kinase Genes in Arabidopsis thaliana

2001 ◽  
Vol 42 (2) ◽  
pp. 231-235 ◽  
Author(s):  
Chiharu Ueguchi ◽  
Hiromi Koizumi ◽  
Tomomi Suzuki ◽  
Takeshi Mizuno
Keyword(s):  
Arabidopsis Thaliana ◽  
Histidine Kinase ◽  
Sensor Histidine Kinase

Homology modelling of a sensor histidine kinase from Aeromonas hydrophila

2009 ◽  
Vol 16 (5) ◽  
pp. 1003-1009 ◽  
Author(s):  
Mobashar Hussain Urf Turabe Fazil ◽  
Sunil Kumar ◽  
Naidu Subbarao ◽  
Haushila Prasad Pandey ◽  
Durg Vijai Singh
Keyword(s):  
Aeromonas Hydrophila ◽  
Histidine Kinase ◽  
Homology Modelling ◽  
Sensor Histidine Kinase

scholarly journals A Novel Redox-Sensing Histidine Kinase That Controls Carbon Catabolite Repression inAzoarcussp. CIB

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
J. Andrés Valderrama ◽  
Helena Gómez-Álvarez ◽  
Zaira Martín-Moldes ◽  
M. Álvaro Berbís ◽  
F. Javier Cañada ◽  
...  
Keyword(s):  
Aromatic Compounds ◽  
Histidine Kinase ◽  
Catabolite Repression ◽  
Carbon Catabolite Repression ◽  
Response Regulator ◽  
Sensor Kinase ◽  
General Role ◽  
Two Component ◽  
Redox Switch ◽  
Redox Sensing

ABSTRACTWe have identified and characterized the AccS multidomain sensor kinase that mediates the activation of the AccR master regulator involved in carbon catabolite repression (CCR) of the anaerobic catabolism of aromatic compounds inAzoarcussp. CIB. A truncated AccS protein that contains only the soluble C-terminal autokinase module (AccS′) accounts for the succinate-dependent CCR control. In vitroassays with purified AccS′ revealed its autophosphorylation, phosphotransfer from AccS′∼P to the Asp60 residue of AccR, and the phosphatase activity toward its phosphorylated response regulator, indicating that the equilibrium between the kinase and phosphatase activities of AccS′ may control the phosphorylation state of the AccR transcriptional regulator. Oxidized quinones, e.g., ubiquinone 0 and menadione, switched the AccS′ autokinase activity off, and three conserved Cys residues, which are not essential for catalysis, are involved in such inhibition. Thiol oxidation by quinones caused a change in the oligomeric state of the AccS′ dimer resulting in the formation of an inactive monomer. This thiol-based redox switch is tuned by the cellular energy state, which can change depending on the carbon source that the cells are using. This work expands the functional diversity of redox-sensitive sensor kinases, showing that they can control new bacterial processes such as CCR of the anaerobic catabolism of aromatic compounds. The AccSR two-component system is conserved in the genomes of some betaproteobacteria, where it might play a more general role in controlling the global metabolic state according to carbon availability.IMPORTANCETwo-component signal transduction systems comprise a sensor histidine kinase and its cognate response regulator, and some have evolved to sense and convert redox signals into regulatory outputs that allow bacteria to adapt to the altered redox environment. The work presented here expands knowledge of the functional diversity of redox-sensing kinases to control carbon catabolite repression (CCR), a phenomenon that allows the selective assimilation of a preferred compound among a mixture of several carbon sources. The newly characterized AccS sensor kinase is responsible for the phosphorylation and activation of the AccR master regulator involved in CCR of the anaerobic degradation of aromatic compounds in the betaproteobacteriumAzoarcussp. CIB. AccS seems to have a thiol-based redox switch that is modulated by the redox state of the quinone pool. The AccSR system is conserved in several betaproteobacteria, where it might play a more general role controlling their global metabolic state.

scholarly journals Routes of phosphoryl group transfer during signal transmission and signal decay in the dimeric sensor histidine kinase ArcB

2018 ◽  
Vol 293 (34) ◽  
pp. 13214-13223 ◽  
Author(s):  
Juan L. Teran-Melo ◽  
Gabriela R. Peña-Sandoval ◽  
Hortencia Silva-Jimenez ◽  
Claudia Rodriguez ◽  
Adrián F. Alvarez ◽  
...  
Keyword(s):  
Histidine Kinase ◽  
Signal Transmission ◽  
Phosphoryl Group ◽  
Sensor Histidine Kinase ◽  
Group Transfer ◽  
Signal Decay

scholarly journals Differential Proteomic Analysis of the Bacillus anthracis Secretome: Distinct Plasmid and Chromosome CO2-Dependent Cross Talk Mechanisms Modulate Extracellular Proteolytic Activities

2006 ◽  
Vol 188 (10) ◽  
pp. 3551-3571 ◽  
Author(s):  
Theodor Chitlaru ◽  
Orit Gat ◽  
Yael Gozlan ◽  
Naomi Ariel ◽  
Avigdor Shafferman
Keyword(s):  
Bacillus Anthracis ◽  
Expression Patterns ◽  
Dependent Manner ◽  
Gene Products ◽  
Virulence Determinants ◽  
Virulence Plasmids ◽  
Proteomic Approach ◽  
Enhanced Expression ◽  
Proteolytic Activities ◽  
Protein Relative Abundance

ABSTRACT The secretomes of a virulent Bacillus anthracis strain and of avirulent strains (cured of the virulence plasmids pXO1 and pXO2), cultured in rich and minimal media, were studied by a comparative proteomic approach. More than 400 protein spots, representing the products of 64 genes, were identified, and a unique pattern of protein relative abundance with respect to the presence of the virulence plasmids was revealed. In minimal medium under high CO2 tension, conditions considered to simulate those encountered in the host, the presence of the plasmids leads to enhanced expression of 12 chromosome-carried genes (10 of which could not be detected in the absence of the plasmids) in addition to expression of 5 pXO1-encoded proteins. Furthermore, under these conditions, the presence of the pXO1 and pXO2 plasmids leads to the repression of 14 chromosomal genes. On the other hand, in minimal aerobic medium not supplemented with CO2, the virulent and avirulent B. anthracis strains manifest very similar protein signatures, and most strikingly, two proteins (the metalloproteases InhA1 and NprB, orthologs of gene products attributed to the Bacillus cereus group PlcR regulon) represent over 90% of the total secretome. Interestingly, of the 64 identified gene products, at least 31 harbor features characteristic of virulence determinants (such as toxins, proteases, nucleotidases, sulfatases, transporters, and detoxification factors), 22 of which are differentially regulated in a plasmid-dependent manner. The nature and the expression patterns of proteins in the various secretomes suggest that distinct CO2-responsive chromosome- and plasmid-encoded regulatory factors modulate the secretion of potential novel virulence factors, most of which are associated with extracellular proteolytic activities.

scholarly journals A Common Virulence Plasmid in Biotype 2 Vibrio vulnificus and Its Dissemination Aided by a Conjugal Plasmid

2007 ◽  
Vol 190 (5) ◽  
pp. 1638-1648 ◽  
Author(s):  
Chung-Te Lee ◽  
Carmen Amaro ◽  
Keh-Ming Wu ◽  
Esmeralda Valiente ◽  
Yi-Feng Chang ◽  
...  
Keyword(s):  
Animal Model ◽  
Human Serum ◽  
Dna Sequences ◽  
Vibrio Vulnificus ◽  
Bacterial Species ◽  
Virulence Plasmid ◽  
Virulence Plasmids ◽  
Sequence Identity ◽  
Loss Of Resistance ◽  
Novel Protein

ABSTRACT Strains of Vibrio vulnificus, a marine bacterial species pathogenic for humans and eels, are divided into three biotypes, and those virulent for eels are classified as biotype 2. All biotype 2 strains possess one or more plasmids, which have been shown to harbor the biotype 2-specific DNA sequences. In this study we determined the DNA sequences of three biotype 2 plasmids: pR99 (68.4 kbp) in strain CECT4999 and pC4602-1 (56.6 kb) and pC4602-2 (66.9 kb) in strain CECT4602. Plasmid pC4602-2 showed 92% sequence identity with pR99. Curing of pR99 from strain CECT4999 resulted in loss of resistance to eel serum and virulence for eels but had no effect on the virulence for mice, an animal model, and resistance to human serum. Plasmids pC4602-2 and pR99 could be transferred to the plasmid-cured strain by conjugation in the presence of pC4602-1, which was self-transmissible, and acquisition of pC4602-2 restored the virulence of the cured strain for eels. Therefore, both pR99 and pC4602-2 were virulence plasmids for eels but not mice. A gene in pR99, which encoded a novel protein and had an equivalent in pC4602-2, was further shown to be essential, but not sufficient, for the resistance to eel serum and virulence for eels. There was evidence showing that pC4602-2 may form a cointegrate with pC4602-1. An investigation of six other biotype 2 strains for the presence of various plasmid markers revealed that they all harbored the virulence plasmid and four of them possessed the conjugal plasmid in addition.

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