scholarly journals Crystal Structure of the Response Regulator 02 Receiver Domain, the Essential YycF Two-Component System of Streptococcus pneumoniae in both Complexed and Native States

2004 ◽  
Vol 186 (9) ◽  
pp. 2872-2879 ◽  
Author(s):  
Colin J. Bent ◽  
Neil W. Isaacs ◽  
Timothy J. Mitchell ◽  
Alan Riboldi-Tunnicliffe
Keyword(s):  
Streptococcus Pneumoniae ◽  
Active Site ◽  
Response Regulator ◽  
Thermotoga Maritima ◽  
Two Component System ◽  
Environmental Signals ◽  
Receiver Domain ◽  
Two Component ◽  
Protein Sequence Homology ◽  
Two Component Signal Transduction

ABSTRACT A variety of bacterial cellular responses to environmental signals are mediated by two-component signal transduction systems comprising a membrane-associated histidine protein kinase and a cytoplasmic response regulator (RR), which interpret specific stimuli and produce a measured physiological response. In RR activation, transient phosphorylation of a highly conserved aspartic acid residue drives the conformation changes needed for full activation of the protein. Sequence homology reveals that RR02 from Streptococcus pneumoniae belongs to the OmpR subfamily of RRs. The structures of the receiver domains from four members of this family, DrrB and DrrD from Thermotoga maritima, PhoB from Escherichia coli, and PhoP from Bacillus subtilis, have been elucidated. These domains are globally very similar in that they are composed of a doubly wound α5β5; however, they differ remarkably in the fine detail of the β4-α4 and α4 regions. The structures presented here reveal a further difference of the geometry in this region. RR02 is has been shown to be the essential RR in the gram-positive bacterium S. pneumoniae R. Lange, C. Wagner, A. de Saizieu, N. Flint, J. Molnos, M. Stieger, P. Caspers, M. Kamber, W. Keck, and K. E. Amrein, Gene 237:223-234, 1999; J. P. Throup, K. K. Koretke, A. P. Bryant, K. A. Ingraham, A. F. Chalker, Y. Ge, A. Marra, N. G. Wallis, J. R. Brown, D. J. Holmes, M. Rosenberg, and M. K. Burnham, Mol. Microbiol. 35:566-576, 2000). RR02 functions as part of a phosphotransfer system that ultimately controls the levels of competence within the bacteria. Here we report the native structure of the receiver domain of RR02 from serotype 4 S. pneumoniae (as well as acetate- and phosphate-bound forms) at different pH levels. Two native structures at 2.3 Å, phased by single-wavelength anomalous diffraction (xenon SAD), and 1.85 Å and a third structure at pH 5.9 revealed the presence of a phosphate ion outside the active site. The fourth structure revealed the presence of an acetate molecule in the active site.

scholarly journals The Two-Component Regulatory System TCS08 Is Involved in Cellobiose Metabolism of Streptococcus pneumoniae R6

2006 ◽  
Vol 189 (4) ◽  
pp. 1342-1350 ◽  
Author(s):  
Stuart J. McKessar ◽  
Regine Hakenbeck
Keyword(s):  
Streptococcus Pneumoniae ◽  
Response Regulator ◽  
Regulatory System ◽  
Phosphotransferase System ◽  
Two Component System ◽  
Transcription Profiles ◽  
Regulatory Systems ◽  
Two Component ◽  
Cognate Response Regulator ◽  
Gram Positive Cocci

ABSTRACT The two-component system TCS08 is one of the regulatory systems that is important for virulence of Streptococcus pneumoniae. In order to investigate the TCS08 regulon, we have analyzed transcription profiles of mutants derived from S. pneumoniae R6 by microarray analysis. Since deletion mutants are often without a significant phenotype, we constructed a mutation in the histidine kinase HK08, T133P, in analogy to the phosphatase mutation T230P in the H box of the S. pneumoniae CiaH kinase described recently (D. Zähner, K. Kaminski, M. van der Linden, T. Mascher, M. Merai, and R. Hakenbeck, J. Mol. Microbiol. Biotechnol. 4:211-216, 2002). In addition, a deletion mutation was constructed in rr08, encoding the cognate response regulator. The most heavily suppressed genes in the hk08 mutant were spr0276 to spr0282, encoding a putative cellobiose phosphoenolpyruvate sugar phosphotransferase system (PTS). Whereas the R6 Smr parent strain and the Δrr08 mutant readily grew on cellobiose, the hk08 mutant and selected mutants with deletions in the PTS cluster did not, strongly suggesting that TCS08 is involved in the catabolism of cellobiose. Homologues of the TCS08 system were found in closely related streptococci and other gram-positive cocci. However, the genes spr0276 to spr0282, encoding the putative cellobiose PTS, represent a genomic island in S. pneumoniae and homologues were found in Streptococcus gordonii only, suggesting that this system might contribute to the pathogenicity potential of the pneumococcus.

scholarly journals Constitutive Activation of Two-Component Response Regulators: Characterization of VirG Activation in Agrobacterium tumefaciens

2006 ◽  
Vol 188 (14) ◽  
pp. 5204-5211 ◽  
Author(s):  
Rong Gao ◽  
Aindrila Mukhopadhyay ◽  
Fang Fang ◽  
David G. Lynn
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Conformational Changes ◽  
Response Regulator ◽  
Structural Features ◽  
Response Regulators ◽  
Two Component System ◽  
Plant Host ◽  
Two Component ◽  
Two Component Signal Transduction

ABSTRACT Response regulators are the ultimate modulators in two-component signal transduction pathways. The N-terminal receiver domains generally accept phosphates from cognate histidine kinases to control output. VirG for example, the response regulator of the VirA/VirG two-component system in Agrobacterium tumefaciens, mediates the expression of virulence genes in response to plant host signals. Response regulators have a highly conserved structure and share a similar conformational activation upon phosphorylation, yet the sequence and structural features that determine or perturb the cooperative activation events are ill defined. Here we use VirG and the unique features of the Agrobacterium system to extend our understanding of the response regulator activation. Two previously isolated constitutive VirG mutants, VirGN54D and VirGI77V/D52E, provide the foundation for our studies. In vivo phosphorylation patterns establish that VirGN54D is able to accumulate phosphates from small-molecule phosphate donors, such as acetyl phosphate, while the VirGI77V/D52E allele carries conformational changes mimicking the active conformation. Further structural alterations on these two alleles begin to reveal the changes necessary for response regulator activation.

scholarly journals Crystal Structures of the Receiver Domain of the Response Regulator PhoP from Escherichia coli in the Absence and Presence of the Phosphoryl Analog Beryllofluoride

2007 ◽  
Vol 189 (16) ◽  
pp. 5987-5995 ◽  
Author(s):  
Priti Bachhawat ◽  
Ann M. Stock
Keyword(s):  
Escherichia Coli ◽  
Crystal Structures ◽  
Response Regulator ◽  
Active State ◽  
Two Component System ◽  
Component System ◽  
Regulatory Domains ◽  
Receiver Domain ◽  
Two Component ◽  
High Concentrations

ABSTRACT The response regulator PhoP is part of the PhoQ/PhoP two-component system involved in responses to depletion of extracellular Mg2+. Here, we report the crystal structures of the receiver domain of Escherichia coli PhoP determined in the absence and presence of the phosphoryl analog beryllofluoride. In the presence of beryllofluoride, the active receiver domain forms a twofold symmetric dimer similar to that seen in structures of other regulatory domains from the OmpR/PhoB family, providing further evidence that members of this family utilize a common mode of dimerization in the active state. In the absence of activating agents, the PhoP receiver domain crystallizes with a similar structure, consistent with the previous observation that high concentrations can promote an active state of PhoP independent of phosphorylation.

Structural insights into the signal transduction mechanism of the K+-sensing two-component system KdpDE

2020 ◽  
Vol 13 (643) ◽  
pp. eaaz2970
Author(s):  
Mingquan Xie ◽  
Mengyuan Wu ◽  
Aidong Han
Keyword(s):  
Signal Transduction ◽  
Response Regulator ◽  
Complex Structure ◽  
Dependent Manner ◽  
Two Component System ◽  
Environmental Signals ◽  
Two Component ◽  
Two Component Systems ◽  
Sense And Respond ◽  
Histidine Phosphorylation

Two-component systems (TCSs), which consist of a histidine kinase (HK) sensor and a response regulator (RR), are important for bacteria to quickly sense and respond to various environmental signals. HKs and RRs typically function as a cognate pair, interacting only with one another to transduce signaling. Precise signal transduction in a TCS depends on the specific interactions between the receiver domain (RD) of the RR and the dimerization and histidine phosphorylation domain (DHp) of the HK. Here, we determined the complex structure of KdpDE, a TCS consisting of the HK KdpD and the RR KdpE, which is responsible for K+ homeostasis. Both the RD and the DNA binding domain (DBD) of KdpE interacted with KdpD. Although the RD of KdpE and the DHp of KdpD contributed to binding specificity, the DBD mediated a distinct interaction with the catalytic ATP-binding (CA) domain of KdpD that was indispensable for KdpDE-mediated signal transduction. Moreover, the DBD-CA interface largely overlapped with that of the DBD-DNA complex, leading to competition between KdpD and its target promoter in a KdpE phosphorylation–dependent manner. In addition, the extended C-terminal tail of the CA domain was critical for stabilizing the interaction with KdpDE and for signal transduction. Together, these data provide a molecular basis for specific KdpD and KdpE interactions that play key roles in efficient signal transduction and transcriptional regulation by this TCS.

scholarly journals Phosphotransfer Reactions of the CbbRRS Three-Protein Two- Component System from Rhodopseudomonas palustris CGA010 Appear To Be Controlled by an Internal Molecular Switch on the Sensor Kinase

2006 ◽  
Vol 189 (2) ◽  
pp. 325-335 ◽  
Author(s):  
Simona Romagnoli ◽  
F. Robert Tabita
Keyword(s):  
Response Regulator ◽  
Rhodopseudomonas Palustris ◽  
Molecular Switch ◽  
Sensor Kinase ◽  
Two Component System ◽  
Conserved Residues ◽  
Component System ◽  
Receiver Domain ◽  
Two Component

ABSTRACT The CbbRRS system is an atypical three-protein two-component system that modulates the expression of the cbb I CO2 fixation operon of Rhodopseudomonas palustris, possibly in response to a redox signal. It consists of a membrane-bound hybrid sensor kinase, CbbSR, with a transmitter and receiver domain, and two response regulator proteins, CbbRR1 and CbbRR2. No detectable helix-turn-helix DNA binding domain is associated with either response regulator, but an HPt domain and a second receiver domain are predicted at the C-terminal region of CbbRR1 and CbbRR2, respectively. The abundance of conserved residues predicted to participate in a His-Asp phosphorelay raised the question of their de facto involvement. In this study, the role of the multiple receiver domains was elucidated in vitro by generating site-directed mutants of the putative conserved residues. Distinct phosphorylation patterns were obtained with two truncated versions of the hybrid sensor kinase, CbbSRT189 and CbbSRR96 (CbbSR beginning at residues T189 and R96, respectively). These constructs also exhibited substantially different affinities for ATP and phosphorylation stability, which was found to be dependent on a conserved Asp residue (Asp-696) within the kinase receiver domain. Asp-696 also played an important role in defining the specificity of phosphorylation for response regulators CbbRR1 or CbbRR2, and this residue appeared to act in conjunction with residues within the region from Arg-96 to Thr-189 at the N terminus of the sensor kinase. The net effect of concerted interactions at these distinct regions of CbbSR created an internal molecular switch that appears to coordinate a unique branched phosphorelay system.

scholarly journals Overexpression of the Response RegulatorevgA of the Two-Component Signal Transduction System Modulates Multidrug Resistance Conferred by Multidrug Resistance Transporters

2001 ◽  
Vol 183 (4) ◽  
pp. 1455-1458 ◽  
Author(s):  
Kunihiko Nishino ◽  
Akihito Yamaguchi
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistance ◽  
Response Regulator ◽  
Multidrug Efflux ◽  
Signal Transduction System ◽  
Two Component System ◽  
Component System ◽  
Two Component ◽  
Two Component Signal Transduction ◽  
Multidrug Resistance Transporters

ABSTRACT Overexpression of evgA, a response regulator of a two-component system, increased multidrug efflux in Escherichia coli. Since overexpression of the emrKY operon, which is controlled by evgAS, could account only for deoxycholate resistance, the evgAS locus apparently controls expression of at least one other multidrug efflux operon.

scholarly journals StoS, a Hybrid Histidine Kinase Sensor of Xanthomonas oryzae pv. oryzae, Is Activated by Sensing Low O2 Concentration and Is Involved in Stress Tolerance and Virulence

2014 ◽  
Vol 27 (6) ◽  
pp. 537-545 ◽  
Author(s):  
Yumi Ikawa ◽  
Ayako Furutani ◽  
Hirokazu Ochiai ◽  
Seiji Tsuge
Keyword(s):  
Stress Tolerance ◽  
Histidine Kinase ◽  
Response Regulator ◽  
Xanthomonas Oryzae ◽  
Low Oxygen ◽  
Environmental Signals ◽  
Receiver Domain ◽  
O2 Concentration ◽  
Two Component Signal Transduction ◽  
Rice Leaves

Bacteria have two-component signal transduction systems (TCSTS), which are important devices for receiving various environmental signals. A TCSTS generally consists of a sensor histidine kinase (HK) and a response regulator (RR) that contains a receiver domain. There are also hybrid-type HK (HyHK) that comprise a HK with a receiver domain within one molecule. In this study, we show that the deletion mutant of a HyHK XOO_0635 (StoS) of Xanthomonas oryzae pv. oryzae, the causal agent of bacterial leaf blight of rice, had decreased stress tolerance to high osmolarity, sodium, and H2O2. Growth of the StoS mutant was delayed, and viability was lower than the wild type in medium and in rice leaves. We found that StoS regulates the expression of various genes including XOO_3715, XOO_0131, and stoS itself. A domain search revealed a PAS domain with a heme pocket in StoS, implying that the HyHK functions as an O2 sensor. When the bacteria were incubated in low oxygen, the StoS-dependent expression of XOO_0131 and XOO_3715 became higher. Therefore, StoS is activated by sensing a low O2 concentration in its environs and is involved in gene expression for adapting to various stressful conditions.

scholarly journals Functional Analysis of theMycobacterium tuberculosis MprAB Two-Component SignalTransductionSystem

2003 ◽  
Vol 71 (12) ◽  
pp. 6962-6970 ◽  
Author(s):  
Thomas C. Zahrt ◽  
Christopher Wozniak ◽  
Denise Jones ◽  
Andrea Trevett
Keyword(s):  
Signal Transduction ◽  
Functional Analysis ◽  
Persistent Infection ◽  
Response Regulator ◽  
Sensor Kinase ◽  
Two Component System ◽  
Two Component ◽  
Two Component Signal Transduction

ABSTRACT The mechanisms utilized by Mycobacterium tuberculosis to establish, maintain, or reactivate from latent infection in the host are largely unknown but likely include genes that mediate adaptation to conditions encountered during persistence. Previously, a two-component signal transduction system, mprAB, was found to be required in M. tuberculosis for establishment and maintenance of persistent infection in a tissue- and stage-specific fashion. To begin to characterize the role of this system in M. tuberculosis physiology and virulence, a functional analysis of the mprA and mprB gene products was initiated. Here, evidence is presented demonstrating that sensor kinase MprB and response regulator MprA function as an intact signal-transducing pair in vitro and in vivo. Sensor kinase MprB can be autophosphorylated, can donate phosphate to MprA, and can act as a phospho-MprA phosphatase in vitro. Correspondingly, response regulator MprA can accept phosphate from MprB or from small phosphodonors including acetyl phosphate. Mutagenesis of residues His249 in MprB and Asp48 in MprA abolished the ability of these proteins to be phosphorylated in vitro. Introduction of these alleles into Mycobacterium bovis BCGattenuated virulence in macrophages in vivo. Together, these results support a role for the mprAB two-component system in M. tuberculosis physiology and pathogenesis. Characterization of two-component signal transduction systems will enhance our understanding of processes regulated by M. tuberculosis during acute and/or persistent infection in the host.

scholarly journals Regulation of Iron Transport in Streptococcus pneumoniae by RitR, an Orphan Response Regulator

2004 ◽  
Vol 186 (23) ◽  
pp. 8123-8136 ◽  
Author(s):  
Andrew T. Ulijasz ◽  
David R. Andes ◽  
Jeremy D. Glasner ◽  
Bernard Weisblum
Keyword(s):  
Signal Transduction ◽  
Streptococcus Pneumoniae ◽  
Iron Transport ◽  
Response Regulator ◽  
Lung Model ◽  
Mrna Levels ◽  
Regulator Gene ◽  
Wild Type ◽  
Two Component ◽  
Two Component Signal Transduction

ABSTRACT RitR (formerly RR489) is an orphan two-component signal transduction response regulator in Streptococcus pneumoniae that has been shown to be required for lung pathogenicity. In the present study, by using the rough strain R800, inactivation of the orphan response regulator gene ritR by allele replacement reduced pathogenicity in a cyclophosphamide-treated mouse lung model but not in a thigh model, suggesting a role for RitR in regulation of tissue-specific virulence factors. Analysis of changes in genome-wide transcript mRNA levels associated with the inactivation of ritR compared to wild-type cells was performed by the use of high-density DNA microarrays. Genes with a change in transcript abundance associated with inactivation of ritR included piuB, encoding an Fe permease subunit, and piuA, encoding an Fe carrier-binding protein. In addition, a dpr ortholog, encoding an H2O2 resistance protein that has been shown to reduce synthesis of reactive oxygen intermediates, was activated in the wild-type (ritR +) strain. Microarray experiments suggested that RitR represses Fe uptake in vitro by negatively regulating the Piu hemin-iron transport system. Footprinting experiments confirmed site-specific DNA-binding activity for RitR and identified three binding sites that partly overlap the +1 site for transcription initiation upstream of piuB. Transcripts belonging to other gene categories found to be differentially expressed in our array studies include those associated with (i) H2O2 resistance, (ii) repair of DNA damage, (iii) sugar transport and capsule biosynthesis, and (iv) two-component signal transduction elements. These observations suggest that RitR is an important response regulator whose primary role is to maintain iron homeostasis in S. pneumoniae. The name ritR (repressor of iron transport) for the orphan response regulator gene, rr489, is proposed.

scholarly journals YycH Regulates the Activity of the Essential YycFG Two-Component System in Bacillus subtilis

2005 ◽  
Vol 187 (15) ◽  
pp. 5419-5426 ◽  
Author(s):  
Hendrik Szurmant ◽  
Kristine Nelson ◽  
Eun-Ja Kim ◽  
Marta Perego ◽  
James A. Hoch
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Histidine Kinase ◽  
Response Regulator ◽  
Temperature Sensitive ◽  
Two Component System ◽  
Component System ◽  
Two Component ◽  
Two Component Signal Transduction ◽  
Regulated Gene Expression

ABSTRACT Of the numerous two-component signal transduction systems found in bacteria, only a very few have proven to be essential for cell viability. Among these is the YycF (response regulator)-YycG (histidine kinase) system, which is highly conserved in and specific to the low-G+C content gram-positive bacteria. Given the pathogenic nature of several members of this class of bacteria, the YycF-YycG system has been suggested as a prime antimicrobial target. In an attempt to identify genes involved in regulation of this two-component system, a transposon mutagenesis study was designed to identify suppressors of a temperature-sensitive YycF mutant in Bacillus subtilis. Suppressors could be identified, and the prime target was the yycH gene located adjacent to yycG and within the same operon. A lacZ reporter assay revealed that YycF-regulated gene expression was elevated in a yycH strain, whereas disruption of any of the three downstream genes within the operon, yycI, yycJ, and yycK, showed no such effect. The concentrations of both YycG and YycF, assayed immunologically, remained unchanged between the wild-type and the yycH strain as determined by immunoassay. Alkaline phosphatase fusion studies showed that YycH is located external to the cell membrane, suggesting that it acts in the regulation of the sensor domain of the YycG sensor histidine kinase. The yycH strain showed a characteristic cell wall defect consistent with the previously suggested notion that the YycF-YycG system is involved in regulating cell wall homeostasis and indicating that either up- or down-regulation of YycF activity affects this homeostatic mechanism.

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