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Manisha Y, Srinivasan M, Jobichen C, Rosenshine I, Sivaraman J. Sensing for survival: specialised regulatory mechanisms of Type III secretion systems in Gram-negative pathogens. Biol Rev Camb Philos Soc 2024; 99:837-863. [PMID: 38217090 DOI: 10.1111/brv.13047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 12/14/2023] [Accepted: 12/19/2023] [Indexed: 01/15/2024]
Abstract
For centuries, Gram-negative pathogens have infected the human population and been responsible for numerous diseases in animals and plants. Despite advancements in therapeutics, Gram-negative pathogens continue to evolve, with some having developed multi-drug resistant phenotypes. For the successful control of infections caused by these bacteria, we need to widen our understanding of the mechanisms of host-pathogen interactions. Gram-negative pathogens utilise an array of effector proteins to hijack the host system to survive within the host environment. These proteins are secreted into the host system via various secretion systems, including the integral Type III secretion system (T3SS). The T3SS spans two bacterial membranes and one host membrane to deliver effector proteins (virulence factors) into the host cell. This multifaceted process has multiple layers of regulation and various checkpoints. In this review, we highlight the multiple strategies adopted by these pathogens to regulate or maintain virulence via the T3SS, encompassing the regulation of small molecules to sense and communicate with the host system, as well as master regulators, gatekeepers, chaperones, and other effectors that recognise successful host contact. Further, we discuss the regulatory links between the T3SS and other systems, like flagella and metabolic pathways including the tricarboxylic acid (TCA) cycle, anaerobic metabolism, and stringent cell response.
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Affiliation(s)
- Yadav Manisha
- Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore
| | - Mahalashmi Srinivasan
- Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore
| | - Chacko Jobichen
- Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore
| | - Ilan Rosenshine
- Department of Microbiology and Molecular Genetics, The Hebrew University of Jerusalem, Ein Kerem, Jerusalem, 91120, Israel
| | - J Sivaraman
- Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore
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2
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Ouyang Z, He W, Jiao M, Yu Q, Guo Y, Refat M, Qin Q, Zhang J, Shi Q, Zheng F, Wen Y. Mechanistic and biophysical characterization of polymyxin resistance response regulator PmrA in Acinetobacter baumannii. Front Microbiol 2024; 15:1293990. [PMID: 38476937 PMCID: PMC10927774 DOI: 10.3389/fmicb.2024.1293990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 02/05/2024] [Indexed: 03/14/2024] Open
Abstract
Introduction Acinetobacter baumannii PmrAB is a crucial two-component regulatory system (TCS) that plays a vital role in conferring resistance to polymyxin. PmrA, a response regulator belonging to the OmpR/PhoB family, is composed of a C-terminal DNA-binding effector domain and an N-terminal receiver domain. The receiver domain can be phosphorylated by PmrB, a transmembrane sensor histidine kinase that interacts with PmrA. Once phosphorylated, PmrA undergoes a conformational change, resulting in the formation of a symmetric dimer in the receiver domain. This conformational change facilitates the recognition of promoter DNA by the DNA-binding domain of PmrA, leading to the activation of adaptive responses. Methods X-ray crystallography was carried out to solve the structure of PmrA receiver domain. Electrophoretic mobility shift assay and Isothermal titration calorimetry were recruited to validate the interaction between the recombinant PmrA protein and target DNA. Field-emission scanning electron microscopy (FE-SEM) was employed to characterize the surface morphology of A. baumannii in both the PmrA knockout and mutation strains. Results The receiver domain of PmrA follows the canonical α5β5 response regulator assembly, which undergoes dimerization upon phosphorylation and activation. Beryllium trifluoride is utilized as an aspartate phosphorylation mimic in this process. Mutations involved in phosphorylation and dimerization significantly affected the expression of downstream pmrC and naxD genes. This impact resulted in an enhanced cell surface smoothness with fewer modifications, ultimately contributing to a decrease in colistin (polymyxin E) and polymyxin B resistance. Additionally, a conservative direct-repeat DNA PmrA binding sequence TTTAAGNNNNNTTTAAG was identified at the promoter region of the pmrC and naxD gene. These findings provide structural insights into the PmrA receiver domain and reveal the mechanism of polymyxin resistance, suggesting that PmrA could be a potential drug target to reverse polymyxin resistance in Acinetobacter baumannii.
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Affiliation(s)
- Zhenlin Ouyang
- Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, Department of Critical Care Medicine, Center for Microbiome Research of Med-X Institute, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Wenbo He
- Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, Department of Critical Care Medicine, Center for Microbiome Research of Med-X Institute, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Min Jiao
- Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, Department of Critical Care Medicine, Center for Microbiome Research of Med-X Institute, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Qinyue Yu
- Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, Department of Critical Care Medicine, Center for Microbiome Research of Med-X Institute, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Yucheng Guo
- Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, Department of Critical Care Medicine, Center for Microbiome Research of Med-X Institute, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Moath Refat
- The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Qian Qin
- Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, Department of Critical Care Medicine, Center for Microbiome Research of Med-X Institute, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Jiaxin Zhang
- Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, Department of Critical Care Medicine, Center for Microbiome Research of Med-X Institute, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Qindong Shi
- Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, Department of Critical Care Medicine, Center for Microbiome Research of Med-X Institute, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Fang Zheng
- The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Yurong Wen
- Shaanxi Provincial Key Laboratory of Sepsis in Critical Care Medicine, Department of Critical Care Medicine, Center for Microbiome Research of Med-X Institute, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
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De Gaetano GV, Lentini G, Famà A, Coppolino F, Beninati C. Antimicrobial Resistance: Two-Component Regulatory Systems and Multidrug Efflux Pumps. Antibiotics (Basel) 2023; 12:965. [PMID: 37370284 DOI: 10.3390/antibiotics12060965] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 05/22/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
The number of multidrug-resistant bacteria is rapidly spreading worldwide. Among the various mechanisms determining resistance to antimicrobial agents, multidrug efflux pumps play a noteworthy role because they export extraneous and noxious substrates from the inside to the outside environment of the bacterial cell contributing to multidrug resistance (MDR) and, consequently, to the failure of anti-infective therapies. The expression of multidrug efflux pumps can be under the control of transcriptional regulators and two-component systems (TCS). TCS are a major mechanism by which microorganisms sense and reply to external and/or intramembrane stimuli by coordinating the expression of genes involved not only in pathogenic pathways but also in antibiotic resistance. In this review, we describe the influence of TCS on multidrug efflux pump expression and activity in some Gram-negative and Gram-positive bacteria. Taking into account the strict correlation between TCS and multidrug efflux pumps, the development of drugs targeting TCS, alone or together with already discovered efflux pump inhibitors, may represent a beneficial strategy to contribute to the fight against growing antibiotic resistance.
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Affiliation(s)
| | - Germana Lentini
- Department of Human Pathology, University of Messina, 98124 Messina, Italy
| | - Agata Famà
- Department of Human Pathology, University of Messina, 98124 Messina, Italy
| | - Francesco Coppolino
- Department of Biomedical, Dental and Imaging Sciences, University of Messina, 98124 Messina, Italy
| | - Concetta Beninati
- Department of Human Pathology, University of Messina, 98124 Messina, Italy
- Scylla Biotech Srl, 98124 Messina, Italy
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In Vivo Role of Two-Component Regulatory Systems in Models of Urinary Tract Infections. Pathogens 2023; 12:pathogens12010119. [PMID: 36678467 PMCID: PMC9861413 DOI: 10.3390/pathogens12010119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/23/2022] [Accepted: 01/08/2023] [Indexed: 01/12/2023] Open
Abstract
Two-component signaling systems (TCSs) are finely regulated mechanisms by which bacteria adapt to environmental conditions by modifying the expression of target genes. In bacterial pathogenesis, TCSs play important roles in modulating adhesion to mucosal surfaces, resistance to antibiotics, and metabolic adaptation. In the context of urinary tract infections (UTI), one of the most common types infections causing significant health problems worldwide, uropathogens use TCSs for adaptation, survival, and establishment of pathogenicity. For example, uropathogens can exploit TCSs to survive inside bladder epithelial cells, sense osmolar variations in urine, promote their ascension along the urinary tract or even produce lytic enzymes resulting in exfoliation of the urothelium. Despite the usefulness of studying the function of TCSs in in vitro experimental models, it is of primary necessity to study bacterial gene regulation also in the context of host niches, each displaying its own biological, chemical, and physical features. In light of this, the aim of this review is to provide a concise description of several bacterial TCSs, whose activity has been described in mouse models of UTI.
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Structural basis of phosphorylation-induced activation of the response regulator VbrR. Acta Biochim Biophys Sin (Shanghai) 2023; 55:43-50. [PMID: 36647726 PMCID: PMC10157535 DOI: 10.3724/abbs.2022200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
<p indent="0mm">Two-component systems typically consist of a paired histidine kinase and response regulator and couple environmental changes to adaptive responses. The response regulator VbrR from <italic>Vibrio parahaemolyticus</italic>, a member of the OmpR/PhoB family, regulates virulence and antibiotic resistance genes. The activation mechanism of VbrR remains unclear. Here, we report the crystal structures of full-length VbrR in complex with DNA in the active conformation and the N-terminal receiver domain (RD) and the C-terminal DNA-binding domain (DBD) in both active and inactive conformations. Structural and biochemical analyses suggest that unphosphorylated VbrR adopts mainly as inactive dimers through the DBD at the autoinhibitory state. The RD undergoes a monomer-to-dimer transition upon phosphorylation, which further induces the transition of DBD from an autoinhibitory dimer to an active dimer and enables its binding with target DNA. Our study suggests a new model for phosphorylation-induced activation of response regulators and sheds light on the pathogenesis of <italic>V</italic>. <italic>parahaemolyticus</italic>. </p>.
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Yan W, Zheng Y, Dou C, Zhang G, Arnaout T, Cheng W. The pathogenic mechanism of Mycobacterium tuberculosis: implication for new drug development. MOLECULAR BIOMEDICINE 2022; 3:48. [PMID: 36547804 PMCID: PMC9780415 DOI: 10.1186/s43556-022-00106-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 11/15/2022] [Indexed: 12/24/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is a tenacious pathogen that has latently infected one third of the world's population. However, conventional TB treatment regimens are no longer sufficient to tackle the growing threat of drug resistance, stimulating the development of innovative anti-tuberculosis agents, with special emphasis on new protein targets. The Mtb genome encodes ~4000 predicted proteins, among which many enzymes participate in various cellular metabolisms. For example, more than 200 proteins are involved in fatty acid biosynthesis, which assists in the construction of the cell envelope, and is closely related to the pathogenesis and resistance of mycobacteria. Here we review several essential enzymes responsible for fatty acid and nucleotide biosynthesis, cellular metabolism of lipids or amino acids, energy utilization, and metal uptake. These include InhA, MmpL3, MmaA4, PcaA, CmaA1, CmaA2, isocitrate lyases (ICLs), pantothenate synthase (PS), Lysine-ε amino transferase (LAT), LeuD, IdeR, KatG, Rv1098c, and PyrG. In addition, we summarize the role of the transcriptional regulator PhoP which may regulate the expression of more than 110 genes, and the essential biosynthesis enzyme glutamine synthetase (GlnA1). All these enzymes are either validated drug targets or promising target candidates, with drugs targeting ICLs and LAT expected to solve the problem of persistent TB infection. To better understand how anti-tuberculosis drugs act on these proteins, their structures and the structure-based drug/inhibitor designs are discussed. Overall, this investigation should provide guidance and support for current and future pharmaceutical development efforts against mycobacterial pathogenesis.
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Affiliation(s)
- Weizhu Yan
- grid.412901.f0000 0004 1770 1022Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-Related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041 China
| | - Yanhui Zheng
- grid.412901.f0000 0004 1770 1022Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-Related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041 China
| | - Chao Dou
- grid.412901.f0000 0004 1770 1022Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-Related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041 China
| | - Guixiang Zhang
- grid.13291.380000 0001 0807 1581Division of Gastrointestinal Surgery, Department of General Surgery and Gastric Cancer center, West China Hospital, Sichuan University, No. 37. Guo Xue Xiang, Chengdu, 610041 China
| | - Toufic Arnaout
- Kappa Crystals Ltd., Dublin, Ireland ,MSD Dunboyne BioNX, Co. Meath, Ireland
| | - Wei Cheng
- grid.412901.f0000 0004 1770 1022Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-Related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041 China
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Abstract
The two-component system PhoP/PhoQ is essential for Salmonella enterica serovar Typhimurium virulence. Here, we report that PhoP is methylated extensively. Two consecutive glutamate (E) and aspartate (D)/E residues, i.e., E8/D9 and E107/E108, and arginine (R) 112 can be methylated. Individual mutation of these above-mentioned residues caused impaired phosphorylation and dimerization or DNA-binding ability of PhoP to a different extent and led to attenuated bacterial virulence. With the help of specific antibodies recognizing methylated E8 and monomethylated R112, we found that the methylation levels of E8 or R112 decreased dramatically when bacteria encountered low magnesium, acidic pH, or phagocytosis by macrophages, under which PhoP can be activated. Furthermore, CheR, a bacterial chemotaxis methyltransferase, was identified to methylate R112. Overexpression of cheR decreased PhoP activity but increased PhoP stability. Together, the current study reveals that methylation plays an important role in regulating PhoP activities in response to environmental cues and, consequently, modulates Salmonella virulence.
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8
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Palethorpe S, Milton ME, Pesci EC, Cavanagh J. Structure of the Acinetobacter baumannii PmrA receiver domain and insights into clinical mutants affecting DNA-binding and promoting colistin resistance. J Biochem 2021; 170:787-800. [PMID: 34585233 DOI: 10.1093/jb/mvab102] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/22/2021] [Indexed: 11/14/2022] Open
Abstract
Acinetobacter baumannii is an insidious emerging nosocomial pathogen that has developed resistance to all available antimicrobials, including the last resort antibiotic, colistin. Colistin resistance often occurs due to mutations in the PmrAB two component regulatory system. To better understand the regulatory mechanisms contributing to colistin resistance, we have biochemically characterized the A. baumannii PmrA response regulator. Initial DNA-binding analysis shows that A. baumannii PmrA bound to the Klebsiella pneumoniae PmrA box motif. This prompted analysis of the putative A. baumannii PmrAB regulon which indicated that the A. baumannii PmrA consensus box is 5'- HTTAAD N5 HTTAAD. Additionally, we provide the first structural information for the A. baumannii PmrA N-terminal domain through X-ray crystallography, and we present a full-length model using molecular modeling. From these studies, we were able to infer the effects of two critical PmrA mutations, PmrA::I13M and PmrA::P102R, both of which confer increased colistin resistance. Based on these data, we suggest structural and dynamic reasons for how these mutations can affect PmrA function and hence encourage resistive traits. Understanding these mechanisms will aid in the development of new targeted antimicrobial therapies.
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Affiliation(s)
- Samantha Palethorpe
- Department of Microbiology and Immunology Brody School of Medicine East Carolina University Greenville, NC 27834 United States
| | - Morgan E Milton
- Department of Biochemistry and Molecular Biology Brody School of Medicine East Carolina University Greenville, NC 27834 United States
| | - Everett C Pesci
- Department of Microbiology and Immunology Brody School of Medicine East Carolina University Greenville, NC 27834 United States
| | - John Cavanagh
- Department of Biochemistry and Molecular Biology Brody School of Medicine East Carolina University Greenville, NC 27834 United States
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Groisman EA, Duprey A, Choi J. How the PhoP/PhoQ System Controls Virulence and Mg 2+ Homeostasis: Lessons in Signal Transduction, Pathogenesis, Physiology, and Evolution. Microbiol Mol Biol Rev 2021; 85:e0017620. [PMID: 34191587 PMCID: PMC8483708 DOI: 10.1128/mmbr.00176-20] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The PhoP/PhoQ two-component system governs virulence, Mg2+ homeostasis, and resistance to a variety of antimicrobial agents, including acidic pH and cationic antimicrobial peptides, in several Gram-negative bacterial species. Best understood in Salmonella enterica serovar Typhimurium, the PhoP/PhoQ system consists o-regulated gene products alter PhoP-P amounts, even under constant inducing conditions. PhoP-P controls the abundance of hundreds of proteins both directly, by having transcriptional effects on the corresponding genes, and indirectly, by modifying the abundance, activity, or stability of other transcription factors, regulatory RNAs, protease regulators, and metabolites. The investigation of PhoP/PhoQ has uncovered novel forms of signal transduction and the physiological consequences of regulon evolution.
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Affiliation(s)
- Eduardo A. Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
- Yale Microbial Sciences Institute, West Haven, Connecticut, USA
| | - Alexandre Duprey
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Jeongjoon Choi
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
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10
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Proteolysis and multimerization regulate signaling along the two-component regulatory system AdeRS. iScience 2021; 24:102476. [PMID: 34113820 PMCID: PMC8169943 DOI: 10.1016/j.isci.2021.102476] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 03/15/2021] [Accepted: 04/23/2021] [Indexed: 11/23/2022] Open
Abstract
Bacterial two-component regulatory systems are ubiquitous environment-sensing signal transducers involved in pathogenesis and antibiotic resistance. The Acinetobacter baumannii two-component regulatory system AdeRS is made up of a sensor histidine kinase AdeS and a cognate response regulator AdeR, which together reduce repression of the multidrug-resistant efflux pump AdeABC. Herein we demonstrate that an N-terminal intrinsically disordered tail in AdeR is important for the upregulation of adeABC expression, although it greatly increases the susceptibility of AdeR to proteasome-mediated degradation. We also show that AdeS assembles into a hexameric state that is necessary for its full histidine kinase activity, which appears to occur via cis autophosphorylation. Taken together, this study demonstrates new structural mechanisms through which two-component systems can transduce environmental signals to impact gene expression and enlightens new potential antimicrobial approach by targeting two-component regulatory systems. Crystal structure of AdeR dimer with traceable N-terminal intrinsically disordered region. N-terminal intrinsically disordered region AdeR is involved in proteasome proteolysis. Crystal structure of AdeS catalytic domain demonstrates cis autophosphorylation. AdeS can assemble into hexamer and is crucial for its full kinase activity.
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11
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de Pina LC, da Silva FSH, Galvão TC, Pauer H, Ferreira RBR, Antunes LCM. The role of two-component regulatory systems in environmental sensing and virulence in Salmonella. Crit Rev Microbiol 2021; 47:397-434. [PMID: 33751923 DOI: 10.1080/1040841x.2021.1895067] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Adaptation to environments with constant fluctuations imposes challenges that are only overcome with sophisticated strategies that allow bacteria to perceive environmental conditions and develop an appropriate response. The gastrointestinal environment is a complex ecosystem that is home to trillions of microorganisms. Termed microbiota, this microbial ensemble plays important roles in host health and provides colonization resistance against pathogens, although pathogens have evolved strategies to circumvent this barrier. Among the strategies used by bacteria to monitor their environment, one of the most important are the sensing and signalling machineries of two-component systems (TCSs), which play relevant roles in the behaviour of all bacteria. Salmonella enterica is no exception, and here we present our current understanding of how this important human pathogen uses TCSs as an integral part of its lifestyle. We describe important aspects of these systems, such as the stimuli and responses involved, the processes regulated, and their roles in virulence. We also dissect the genomic organization of histidine kinases and response regulators, as well as the input and output domains for each TCS. Lastly, we explore how these systems may be promising targets for the development of antivirulence therapeutics to combat antibiotic-resistant infections.
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Affiliation(s)
- Lucindo Cardoso de Pina
- Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.,Programa de Pós-Graduação em Biociências, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil.,Programa de Pós-Graduação Ciência para o Desenvolvimento, Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | | | - Teca Calcagno Galvão
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Heidi Pauer
- Centro de Desenvolvimento Tecnológico em Saúde, Fundação Oswaldo Cruz, Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças de Populações Negligenciadas, Rio de Janeiro, Brazil
| | | | - L Caetano M Antunes
- Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.,Centro de Desenvolvimento Tecnológico em Saúde, Fundação Oswaldo Cruz, Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças de Populações Negligenciadas, Rio de Janeiro, Brazil.,Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
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12
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Alam P, Alqahtani AS, Mabood Husain F, Tabish Rehman M, Alajmi MF, Noman OM, El Gamal AA, Al-Massarani SM, Shavez Khan M. Siphonocholin isolated from red sea sponge Siphonochalina siphonella attenuates quorum sensing controlled virulence and biofilm formation. Saudi Pharm J 2020; 28:1383-1391. [PMID: 33250645 PMCID: PMC7679466 DOI: 10.1016/j.jsps.2020.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 09/07/2020] [Indexed: 01/25/2023] Open
Abstract
Increasing incidence of multi-drug resistant bacterial pathogens, especially in clinical settings, has been developed into a grave health situation. The drug resistance problem demands the necessity for alternative unique therapeutic policies. One such tactic is targeting the quorum sensing (QS) controlled virulence and biofilm production. In this study, we evaluated a marine steroid Siphonocholin (Syph-1) isolated from Siphonochalina siphonella against Chromobacterium violaceum (CV) 12472, Pseudomonas aeruginosa (PAO1), Methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii (BAA) for biofilm and pellicle formation inhibition, and anti-QS property. MIC of Syph-1 against MRSA, CV, PAO1 was found as 64 µg/mL and 256 µg/mL against BAA. At selected sub-MICs, Syph-1 significantly (P ≤ 0.05) decreased the production of QS regulated virulence functions of CV12472 (violacein) and PAO1 [elastase, total protease, pyocyanin, chitinase, exopolysaccharides, and swarming motility]. The Syph-1 significantly decreased (p = 0.005) biofilm formation ability of tested bacterial pathogens, at sub-MIC level (PAO1 > MRSA > CV > BAA) and pellicle formation in A. baumannii (at 128 µg/mL). Molecular docking and simulation results indicated that Siph-1 was bound at the active site of BfmR N-terminal domain with high affinity. This study highlights the anti-QS and anti-biofilm activity of Syph-1 against bacterial pathogens reflecting its broad spectrum anti-infective potential.
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Affiliation(s)
- Perwez Alam
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Ali S. Alqahtani
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Fohad Mabood Husain
- Department of Food Science and Nutrition, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Md. Tabish Rehman
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Mohamed F. Alajmi
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Omar M. Noman
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Ali A. El Gamal
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Shaza M. Al-Massarani
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Mohammad Shavez Khan
- National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan, India
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Gangathraprabhu B, Kannan S, Santhanam G, Suryadevara N, Maruthamuthu M. A review on the origin of multidrug-resistant Salmonella and perspective of tailored phoP gene towards avirulence. Microb Pathog 2020; 147:104352. [PMID: 32592823 DOI: 10.1016/j.micpath.2020.104352] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 05/04/2020] [Accepted: 06/14/2020] [Indexed: 01/21/2023]
Abstract
Salmonellosis continues to remain a health problem as the causative organism Salmonella spp. developed resistance to many of the antibiotics. As per World Health Organization (WHO), it is estimated that enteric fever, accounts for almost 16 million cases annually and over 600,000 deaths worldwide. Recent data revealed that the multi-drug resistance (MDR) rate of enteric fever was as high as 70% in Asian countries, as compared with the overall reported incidence of 50%. Emergence of MDR typhoid fever demands the use of newer antibiotics which also not offer promising effect in recent days. Effective antimicrobial therapy is required to control morbidity and prevent death from typhoid fever. The studies on PhoP/Q regulation revealed it as a best-characterized transcriptional regulation; a two-component system required for Salmonella pathogenesis which controls the expression of more than 40 genes. The PhoP DNA binding proteins possess positively charged amino acids such as arginine, lysine and histidine which present in the DNA binding site. Prevention of PhoP binding in phoP box may ultimately prevent the expression of many regulatory mechanism which plays vital role in Salmonella virulence. Deepness study of PhoP protein and various mutation swots may offer effectual controlling of MDR Salmonella.
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Affiliation(s)
- Balasubramani Gangathraprabhu
- Department of Microbial Technology, School of Biological Sciences, Madurai Kamaraj University, Madurai, 625021, Tamilnadu, India
| | - Suganya Kannan
- Central Research laboratory, Vinayaka Mission Research Foundation (Deemed to be University), Vinayaka Missions Medical College and Hospital, Karaikal, Puducherry, India
| | - Geethanjali Santhanam
- Department of Home Science, Mother Teresa Women's University, Kodaikanal, Tamilnadu, India
| | - Nagaraja Suryadevara
- Department of Biomedical Sciences, MAHSA University, Jenjarom, 42610, Selangor Dahrul Ehsan, Malaysia
| | - Murugan Maruthamuthu
- Department of Microbial Technology, School of Biological Sciences, Madurai Kamaraj University, Madurai, 625021, Tamilnadu, India.
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14
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Ouyang Z, Zheng F, Chew JY, Pei Y, Zhou J, Wen K, Han M, Lemieux MJ, Hwang PM, Wen Y. Deciphering the activation and recognition mechanisms of Staphylococcus aureus response regulator ArlR. Nucleic Acids Res 2020; 47:11418-11429. [PMID: 31598698 PMCID: PMC6868441 DOI: 10.1093/nar/gkz891] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 09/21/2019] [Accepted: 10/01/2019] [Indexed: 01/22/2023] Open
Abstract
Staphylococcus aureus ArlRS is a key two-component regulatory system necessary for adhesion, biofilm formation, and virulence. The response regulator ArlR consists of a C-terminal DNA-binding effector domain and an N-terminal receiver domain that is phosphorylated by ArlS, the cognate transmembrane sensor histidine kinase. We demonstrate that the receiver domain of ArlR adopts the canonical α5β5 response regulator assembly, which dimerizes upon activation, using beryllium trifluoride as an aspartate phosphorylation mimic. Activated ArlR recognizes a 20-bp imperfect inverted repeat sequence in the ica operon, which is involved in intercellular adhesion polysaccharide production. Crystal structures of the inactive and activated forms reveal that activation induces a significant conformational change in the β4-α4 and β5-α5-connecting loops, in which the α4 and α5 helices constitute the homodimerization interface. Crystal structures of the DNA-binding ArlR effector domain indicate that it is able to dimerize via a non-canonical β1–β2 hairpin domain swapping, raising the possibility of a new mechanism for signal transduction from the receiver domain to effector domain. Taken together, the current study provides structural insights into the activation of ArlR and its recognition, adding to the diversity of response regulation mechanisms that may inspire novel antimicrobial strategies specifically targeting Staphylococcus.
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Affiliation(s)
- Zhenlin Ouyang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an, China.,Institute of Medical Research, Northwestern Polytechnical University, Xi'an, China
| | - Fang Zheng
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Jared Y Chew
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton T6G 2R3, Alberta, Canada
| | - Yingmei Pei
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Jinhong Zhou
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Keqing Wen
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - Miao Han
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an, China
| | - M Joanne Lemieux
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton T6G 2R3, Alberta, Canada
| | - Peter M Hwang
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton T6G 2R3, Alberta, Canada
| | - Yurong Wen
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an, China.,Institute of Medical Research, Northwestern Polytechnical University, Xi'an, China.,Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton T6G 2R3, Alberta, Canada
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15
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Huang J, Li C, Song J, Velkov T, Wang L, Zhu Y, Li J. Regulating polymyxin resistance in Gram-negative bacteria: roles of two-component systems PhoPQ and PmrAB. Future Microbiol 2020; 15:445-459. [PMID: 32250173 DOI: 10.2217/fmb-2019-0322] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Polymyxins (polymyxin B and colistin) are last-line antibiotics against multidrug-resistant Gram-negative pathogens. Polymyxin resistance is increasing worldwide, with resistance most commonly regulated by two-component systems such as PmrAB and PhoPQ. This review discusses the regulatory mechanisms of PhoPQ and PmrAB in mediating polymyxin resistance, from receiving an external stimulus through to activation of genes responsible for lipid A modifications. By analyzing the reported nonsynonymous substitutions in each two-component system, we identified the domains that are critical for polymyxin resistance. Notably, for PmrB 71% of resistance-conferring nonsynonymous mutations occurred in the HAMP (present in histidine kinases, adenylate cyclases, methyl accepting proteins and phosphatase) linker and DHp (dimerization and histidine phosphotransfer) domains. These results enhance our understanding of the regulatory mechanisms underpinning polymyxin resistance and may assist with the development of new strategies to minimize resistance emergence.
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Affiliation(s)
- Jiayuan Huang
- Biomedicine Discovery Institute & Department of Microbiology, Monash University, Melbourne 3800, Australia
| | - Chen Li
- Biomedicine Discovery Institute & Department of Biochemistry & Molecular Biology, Monash University, Melbourne 3800, Australia.,Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, Zurich 8093, Switzerland
| | - Jiangning Song
- Biomedicine Discovery Institute & Department of Biochemistry & Molecular Biology, Monash University, Melbourne 3800, Australia
| | - Tony Velkov
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry & Health Sciences, The University of Melbourne, Melbourne 3010, Australia
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Yan Zhu
- Biomedicine Discovery Institute & Department of Microbiology, Monash University, Melbourne 3800, Australia
| | - Jian Li
- Biomedicine Discovery Institute & Department of Microbiology, Monash University, Melbourne 3800, Australia
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16
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Structural basis of molecular logic OR in a dual-sensor histidine kinase. Proc Natl Acad Sci U S A 2019; 116:19973-19982. [PMID: 31527275 DOI: 10.1073/pnas.1910855116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Signal detection and integration by sensory proteins constitute the critical molecular events as living organisms respond to changes in a complex environment. Many sensory proteins adopt a modular architecture that integrates the perception of distinct chemical or physical signals and the generation of a biological response in the same protein molecule. Currently, how signal perception and integration are achieved in such a modular, often dimeric, framework remains elusive. Here, we report a dynamic crystallography study on the tandem sensor domains of a dual-sensor histidine kinase PPHK (phosphorylation-responsive photosensitive histidine kinase) that operates a molecular logic OR, by which the output kinase activity is modulated by a phosphorylation signal and a light signal. A joint analysis of ∼170 crystallographic datasets probing different signaling states shows remarkable dimer asymmetry as PPHK responds to the input signals and transitions from one state to the other. Supported by mutational data and structural analysis, these direct observations reveal the working mechanics of the molecular logic OR in PPHK, where the light-induced bending of a long signaling helix at the dimer interface is counteracted by the ligand-induced structural changes from a different sensor domain. We propose that the logic OR of PPHK, together with an upstream photoreceptor, implements a "long-pass" red light response distinct from those accomplished by classical phytochromes.
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17
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Tsai KC, Hung PP, Cheng CF, Chen C, Tseng TS. Exploring the mode of action of inhibitors targeting the PhoP response regulator of Salmonella enterica through comprehensive pharmacophore approaches. RSC Adv 2019; 9:9308-9312. [PMID: 35517705 PMCID: PMC9062048 DOI: 10.1039/c9ra00620f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 02/28/2019] [Indexed: 11/23/2022] Open
Abstract
The PhoQ/PhoP two-component system regulates the physiological and virulence functions of Salmonella enterica. However, the mode of action of known PhoP inhibitors is unclear. We systematically constructed a pharmacophore model of inhibitors to probe the interface pharmacophore model of the PhoP dimer, coupling it with Ligplot analysis. We found that these inhibitors bind on the α5-helix, altering the conformation and interfering with PhoP binding on DNA. Comprehensive pharmacophore approaches explore the mode of action of inhibitors targeting PhoP response regulator of Salmonella enterica.![]()
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Affiliation(s)
- Keng-Chang Tsai
- National Research Institute of Chinese Medicine, Ministry of Health and Welfare Taipei 112 Taiwan.,The PhD Program in Medical Biotechnology, College of Medical Science and Technology, Taipei Medical University Taipei Taiwan
| | - Po-Pin Hung
- Division of Infectious Disease, Department of Internal Medicine, Taipei Tzu Chi Hospital, The Buddhist Tzu Chi Medical Foundation New Taipei City 231 Taiwan
| | - Ching-Feng Cheng
- Department of Pediatrics, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taipei and Tzu Chi University Hualien Taiwan.,Institute of Biomedical Sciences, Academia Sinica Taipei 115 Taiwan
| | - Chinpan Chen
- Institute of Biomedical Sciences, Academia Sinica Taipei 115 Taiwan
| | - Tien-Sheng Tseng
- Department of Research, Taipei Tzu Chi Hospital, The Buddhist Tzu Chi Medical Foundation New Taipei City 231 Taiwan
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18
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Mechaly AE, Haouz A, Sassoon N, Buschiazzo A, Betton JM, Alzari PM. Conformational plasticity of the response regulator CpxR, a key player in Gammaproteobacteria virulence and drug-resistance. J Struct Biol 2018; 204:165-171. [DOI: 10.1016/j.jsb.2018.08.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 01/27/2023]
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19
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Regulation of Streptomyces Chitinases by Two-Component Signal Transduction Systems and their Post Translational Modifications: A Review. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2018. [DOI: 10.22207/jpam.12.3.45] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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20
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Babben S, Schliephake E, Janitza P, Berner T, Keilwagen J, Koch M, Arana-Ceballos FA, Templer SE, Chesnokov Y, Pshenichnikova T, Schondelmaier J, Börner A, Pillen K, Ordon F, Perovic D. Association genetics studies on frost tolerance in wheat (Triticum aestivum L.) reveal new highly conserved amino acid substitutions in CBF-A3, CBF-A15, VRN3 and PPD1 genes. BMC Genomics 2018; 19:409. [PMID: 29843596 PMCID: PMC5975666 DOI: 10.1186/s12864-018-4795-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 05/14/2018] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Understanding the genetic basis of frost tolerance (FT) in wheat (Triticum aestivum L.) is essential for preventing yield losses caused by frost due to cellular damage, dehydration and reduced metabolism. FT is a complex trait regulated by a number of genes and several gene families. Availability of the wheat genomic sequence opens new opportunities for exploring candidate genes diversity for FT. Therefore, the objectives of this study were to identity SNPs and insertion-deletion (indels) in genes known to be involved in frost tolerance and to perform association genetics analysis of respective SNPs and indels on FT. RESULTS Here we report on the sequence analysis of 19 candidate genes for FT in wheat assembled using the Chinese Spring IWGSC RefSeq v1.0. Out of these, the tandem duplicated C-repeat binding factors (CBF), i.e. CBF-A3, CBF-A5, CBF-A10, CBF-A13, CBF-A14, CBF-A15, CBF-A18, the vernalisation response gene VRN-A1, VRN-B3, the photoperiod response genes PPD-B1 and PPD-D1 revealed association to FT in 235 wheat cultivars. Within six genes (CBF-A3, CBF-A15, VRN-A1, VRN-B3, PPD-B1 and PPD-D1) amino acid (AA) substitutions in important protein domains were identified. The amino acid substitution effect in VRN-A1 on FT was confirmed and new AA substitutions in CBF-A3, CBF-A15, VRN-B3, PPD-B1 and PPD-D1 located at highly conserved sites were detected. Since these results rely on phenotypic data obtained at five locations in 2 years, detection of significant associations of FT to AA changes in CBF-A3, CBF-A15, VRN-A1, VRN-B3, PPD-B1 and PPD-D1 may be exploited in marker assisted breeding for frost tolerance in winter wheat. CONCLUSIONS A set of 65 primer pairs for the genes mentioned above from a previous study was BLASTed against the IWGSC RefSeq resulting in the identification of 39 primer combinations covering the full length of 19 genes. This work demonstrates the usefulness of the IWGSC RefSeq in specific primer development for highly conserved gene families in hexaploid wheat and, that a candidate gene association genetics approach based on the sequence data is an efficient tool to identify new alleles of genes important for the response to abiotic stress in wheat.
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Affiliation(s)
- Steve Babben
- Julius Kühn-Institut (JKI), Federal Research Centre for Cultivated Plants, Institute for Resistance Research and Stress Tolerance, Erwin-Baur-Str. 27, 06484 Quedlinburg, Saxony-Anhalt Germany
- Martin Luther University Halle-Wittenberg (MLU), Institute of Agricultural and Nutritional Sciences, Betty-Heimann-Str. 5, 06120 Halle (Saale), Saxony-Anhalt Germany
| | - Edgar Schliephake
- Julius Kühn-Institut (JKI), Federal Research Centre for Cultivated Plants, Institute for Resistance Research and Stress Tolerance, Erwin-Baur-Str. 27, 06484 Quedlinburg, Saxony-Anhalt Germany
| | - Philipp Janitza
- Martin Luther University Halle-Wittenberg (MLU), Institute of Agricultural and Nutritional Sciences, Betty-Heimann-Str. 5, 06120 Halle (Saale), Saxony-Anhalt Germany
| | - Thomas Berner
- Julius Kühn-Institut (JKI), Federal Research Centre for Cultivated Plants, Institute for Biosafety in Plant Biotechnology, Erwin-Baur-Str. 27, 06484 Quedlinburg, Saxony-Anhalt Germany
| | - Jens Keilwagen
- Julius Kühn-Institut (JKI), Federal Research Centre for Cultivated Plants, Institute for Biosafety in Plant Biotechnology, Erwin-Baur-Str. 27, 06484 Quedlinburg, Saxony-Anhalt Germany
| | - Michael Koch
- Deutsche Saatveredelung AG (DSV), Weißenburger Str. 5, 59557 Lippstadt, Nordrhein-Westfalen Germany
| | - Fernando Alberto Arana-Ceballos
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Resources Genetics and Reproduction, Correnstraße 3, 06466 Seeland OT Gatersleben, Saxony-Anhalt Germany
| | - Sven Eduard Templer
- Julius Kühn-Institut (JKI), Federal Research Centre for Cultivated Plants, Institute for Resistance Research and Stress Tolerance, Erwin-Baur-Str. 27, 06484 Quedlinburg, Saxony-Anhalt Germany
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9B, 50931 Cologne, Nordrhein-Westfalen Germany
| | - Yuriy Chesnokov
- Agrophysical Research Institute (AFI), Grazhdanskii prosp. 14, 195220 St. Petersburg, Russia
| | - Tatyana Pshenichnikova
- Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Prospekt Lavrentyeva 10, 630090 Novosibirsk, Russia
| | - Jörg Schondelmaier
- Saaten-Union Biotec GmbH, Hovedisser Str. 94, 33818 Leopoldshoehe, Nordrhein-Westfalen Germany
| | - Andreas Börner
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Resources Genetics and Reproduction, Correnstraße 3, 06466 Seeland OT Gatersleben, Saxony-Anhalt Germany
| | - Klaus Pillen
- Martin Luther University Halle-Wittenberg (MLU), Institute of Agricultural and Nutritional Sciences, Betty-Heimann-Str. 3, 06120 Halle (Saale), Saxony-Anhalt Germany
| | - Frank Ordon
- Julius Kühn-Institut (JKI), Federal Research Centre for Cultivated Plants, Institute for Resistance Research and Stress Tolerance, Erwin-Baur-Str. 27, 06484 Quedlinburg, Saxony-Anhalt Germany
| | - Dragan Perovic
- Julius Kühn-Institut (JKI), Federal Research Centre for Cultivated Plants, Institute for Resistance Research and Stress Tolerance, Erwin-Baur-Str. 27, 06484 Quedlinburg, Saxony-Anhalt Germany
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21
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Kou X, Liu Y, Li C, Liu M, Jiang L. Dimerization and Conformational Exchanges of the Receiver Domain of Response Regulator PhoB from Escherichia coli. J Phys Chem B 2018; 122:5749-5757. [DOI: 10.1021/acs.jpcb.8b01034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xinhui Kou
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
- Graduate University of Chinese Academy of Sciences, 19A Yuquanlu, Beijing 100049, China
| | - Yixiang Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Conggang Li
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Maili Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Ling Jiang
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
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22
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Draughn GL, Milton ME, Feldmann EA, Bobay BG, Roth BM, Olson AL, Thompson RJ, Actis LA, Davies C, Cavanagh J. The Structure of the Biofilm-controlling Response Regulator BfmR from Acinetobacter baumannii Reveals Details of Its DNA-binding Mechanism. J Mol Biol 2018; 430:806-821. [PMID: 29438671 DOI: 10.1016/j.jmb.2018.02.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 02/02/2018] [Accepted: 02/03/2018] [Indexed: 01/19/2023]
Abstract
The rise of drug-resistant bacterial infections coupled with decreasing antibiotic efficacy poses a significant challenge to global health care. Acinetobacter baumannii is an insidious, emerging bacterial pathogen responsible for severe nosocomial infections aided by its ability to form biofilms. The response regulator BfmR, from the BfmR/S two-component system, is the master regulator of biofilm initiation in A. baumannii and is a tractable therapeutic target. Here we present the structure of A. baumannii BfmR using a hybrid approach combining X-ray crystallography, nuclear magnetic resonance spectroscopy, chemical crosslinking mass spectrometry, and molecular modeling. We also show that BfmR binds the previously proposed bfmRS promoter sequence with moderate affinity. While BfmR shares many traits with other OmpR/PhoB family response regulators, some unusual properties were observed. Most importantly, we observe that when phosphorylated, BfmR binds this promoter sequence with a lower affinity than when not phosphorylated. All other OmpR/PhoB family members studied to date show an increase in DNA-binding affinity upon phosphorylation. Understanding the structural and biochemical mechanisms of BfmR will aid in the development of new antimicrobial therapies.
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Affiliation(s)
- G Logan Draughn
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA; Department of Discovery Sciences, RTI International, 3040 E. Cornwallis Road, Research Triangle Park, NC 27709, USA
| | - Morgan E Milton
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA; Department of Discovery Sciences, RTI International, 3040 E. Cornwallis Road, Research Triangle Park, NC 27709, USA
| | - Erik A Feldmann
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Benjamin G Bobay
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Braden M Roth
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Andrew L Olson
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Richele J Thompson
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Luis A Actis
- Department of Microbiology, Miami University, Oxford, OH 45056, USA
| | - Christopher Davies
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - John Cavanagh
- Department of Discovery Sciences, RTI International, 3040 E. Cornwallis Road, Research Triangle Park, NC 27709, USA.
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23
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Qing X, De Weerdt A, De Maeyer M, Steenackers H, Voet A. Rational design of small molecules that modulate the transcriptional function of the response regulator PhoP. Biochem Biophys Res Commun 2018; 495:375-381. [DOI: 10.1016/j.bbrc.2017.11.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 11/06/2017] [Indexed: 12/18/2022]
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24
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Wen Y, Ouyang Z, Yu Y, Zhou X, Pei Y, Devreese B, Higgins PG, Zheng F. Mechanistic insight into how multidrug resistant Acinetobacter baumannii response regulator AdeR recognizes an intercistronic region. Nucleic Acids Res 2017; 45:9773-9787. [PMID: 28934482 PMCID: PMC5766154 DOI: 10.1093/nar/gkx624] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 07/07/2017] [Indexed: 01/22/2023] Open
Abstract
AdeR-AdeS is a two-component regulatory system, which controls expression of the adeABC efflux pump involved in Acinetobacter baumannii multidrug resistance. AdeR is a response regulator consisting of an N-terminal receiver domain and a C-terminal DNA-binding-domain. AdeR binds to a direct-repeat DNA in the intercistronic region between adeR and adeABC. We demonstrate a markedly high affinity binding between unphosphorylated AdeR and DNA with a dissociation constant of 20 nM. In addition, we provide a 2.75 Å crystal structure of AdeR DNA-binding-domain complexed with the intercistronic DNA. This structure shows that the α3 and β hairpin formed by β5-β6 interacts with the major and minor groove of the DNA, which in turn leads to the introduction of a bend. The AdeR receiver domain structure revealed a dimerization motif mediated by a gearwheel-like structure involving the D108F109-R122 motif through cation π stack interaction. The structure of AdeR receiver domain bound with magnesium indicated a conserved Glu19Asp20-Asp63 magnesium-binding motif, and revealed that the potential phosphorylation site Asp63OD1 forms a hydrogen bond with Lys112. We thus dissected the mechanism of how AdeR recognizes the intercistronic DNA, which leads to a diverse mode of response regulation. Unlocking the AdeRS mechanism provides ways to circumvent A. baumannii antibiotic resistance.
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Affiliation(s)
- Yurong Wen
- Center for Translational Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710061, China.,Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an 710061, China
| | - Zhenlin Ouyang
- Center for Translational Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710061, China
| | - Yue Yu
- Center for Translational Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710061, China
| | - Xiaorong Zhou
- Center for Translational Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710061, China
| | - Yingmei Pei
- Center for Translational Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710061, China
| | - Bart Devreese
- Unit for Biological Mass Spectrometry and Proteomics, Laboratory for Protein Biochemistry and Biomolecular Engineering (L-ProBE), Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Paul G Higgins
- Institute for Medical Microbiology, Immunology, and Hygiene, University of Cologne, Goldenfelsstr.19-21, 50935 Cologne, Germany.,German Center for Infection Research (DZIF), partner site Bonn-Cologne, Cologne, Germany
| | - Fang Zheng
- Department of Biochemistry and Molecular Biology, The Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong University, Xi'an 710061, China
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25
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Qing XY, Steenackers H, Venken T, De Maeyer M, Voet A. Computational Studies of the Active and Inactive Regulatory Domains of Response Regulator PhoP Using Molecular Dynamics Simulations. Mol Inform 2017; 36. [PMID: 28598557 DOI: 10.1002/minf.201700031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 05/30/2017] [Indexed: 12/25/2022]
Abstract
The response regulator PhoP is part of the PhoP/PhoQ two-component system, which is responsible for regulating the expression of multiple genes involved in controlling virulence, biofilm formation, and resistance to antimicrobial peptides. Therefore, modulating the transcriptional function of the PhoP protein is a promising strategy for developing new antimicrobial agents. There is evidence suggesting that phosphorylation-mediated dimerization in the regulatory domain of PhoP is essential for its transcriptional function. Disruption or stabilization of protein-protein interactions at the dimerization interface may inhibit or enhance the expression of PhoP-dependent genes. In this study, we performed molecular dynamics simulations on the active and inactive dimers and monomers of the PhoP regulatory domains, followed by pocket-detecting screenings and a quantitative hot-spot analysis in order to assess the druggability of the protein. Consistent with prior hypothesis, the calculation of the binding free energy shows that phosphorylation enhances dimerization of PhoP. Furthermore, we have identified two different putative binding sites at the dimerization active site (the α4-β5-α5 face) with energetic "hot-spot" areas, which could be used to search for modulators of protein-protein interactions. This study delivers insight into the dynamics and druggability of the dimerization interface of the PhoP regulatory domain, and may serve as a basis for the rational identification of new antimicrobial drugs.
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Affiliation(s)
- Xiao-Yu Qing
- Laboratory for Biomolecular Modelling, and Laboratory for Biomolecular Modelling and design, the Chemistry Department, KULeuven, Celestijnenlaan 200G-bus2403, Heverlee, Belgium
| | - Hans Steenackers
- Centre of Microbial and Plant Genetics, KULeuven, Kasteelpark Arenberg 20-bus2460, Belgium
| | - Tom Venken
- Flemish Institute for Technological Research, VITO, Boeretang 200, 2400, MOL, Belgium
| | - Marc De Maeyer
- Laboratory for Biomolecular Modelling, and Laboratory for Biomolecular Modelling and design, the Chemistry Department, KULeuven, Celestijnenlaan 200G-bus2403, Heverlee, Belgium
| | - Arnout Voet
- Laboratory for Biomolecular Modelling, and Laboratory for Biomolecular Modelling and design, the Chemistry Department, KULeuven, Celestijnenlaan 200G-bus2403, Heverlee, Belgium
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Miguel-Romero L, Casino P, Landete JM, Monedero V, Zúñiga M, Marina A. The malate sensing two-component system MaeKR is a non-canonical class of sensory complex for C4-dicarboxylates. Sci Rep 2017; 7:2708. [PMID: 28577341 PMCID: PMC5457438 DOI: 10.1038/s41598-017-02900-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 04/20/2017] [Indexed: 11/09/2022] Open
Abstract
Microbial colonization of different environments is enabled to a great extent by the plasticity of their sensory mechanisms, among them, the two-component signal transduction systems (TCS). Here, an example of TCS plasticity is presented: the regulation of L-malate catabolism via malic enzyme by MaeRK in Lactobacillales. MaeKR belongs to the citrate family of TCS as the Escherichia coli DcuSR system. We show that the Lactobacillus casei histidine-kinase MaeK is defective in autophosphorylation activity as it lacks a functional catalytic and ATP binding domain. The cognate response regulator MaeR was poorly phosphorylated at its phosphoacceptor Asp in vitro. This phosphorylation, however, enhanced MaeR binding in vitro to its target sites and it was required for induction of regulated genes in vivo. Elucidation of the MaeR structure revealed that response regulator dimerization is accomplished by the swapping of α4-β5-α5 elements between two monomers, generating a phosphoacceptor competent conformation. Sequence and phylogenetic analyses showed that the MaeKR peculiarities are not exclusive to L. casei as they are shared by the rest of orthologous systems of Lactobacillales. Our results reveal MaeKR as a non-canonical TCS displaying distinctive features: a swapped response regulator and a sensor histidine kinase lacking ATP-dependent kinase activity.
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Affiliation(s)
- L Miguel-Romero
- Department of Genomic and Proteomic, Instituto de Biomedicina de Valencia (IBV-CSIC), Jaume Roig 11, 46010, Valencia, Spain
| | - P Casino
- Departamento de Bioquímica, Universitat de València, Dr Moliner 50, 46100, Burjassot, Spain.,Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, Dr Moliner 50, 46100, Burjassot, Spain
| | - J M Landete
- Departamento de Biotecnología de Alimentos, Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Av. Agustín Escardino 7, 46980, Paterna, Valencia, Spain.,Departamento de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de La Coruña Km 7.5, 28040, Madrid, Spain
| | - V Monedero
- Departamento de Biotecnología de Alimentos, Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Av. Agustín Escardino 7, 46980, Paterna, Valencia, Spain
| | - M Zúñiga
- Departamento de Biotecnología de Alimentos, Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Av. Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
| | - A Marina
- Department of Genomic and Proteomic, Instituto de Biomedicina de Valencia (IBV-CSIC), Jaume Roig 11, 46010, Valencia, Spain. .,Group 739 of the Centro de Investigación Biomédica en Red sobre Enfermedades Raras (CIBERER) del Instituto de Salud Carlos III, -, Spain.
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Crystal structure of the inactive state of the receiver domain of Spo0A from Paenisporosarcina sp. TG-14, a psychrophilic bacterium isolated from an Antarctic glacier. J Microbiol 2017; 55:464-474. [PMID: 28281198 DOI: 10.1007/s12275-017-6599-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 01/13/2017] [Accepted: 01/25/2017] [Indexed: 10/20/2022]
Abstract
The two-component phosphorelay system is the most prevalent mechanism for sensing and transducing environmental signals in bacteria. Spore formation, which relies on the two-component phosphorelay system, enables the long-term survival of the glacial bacterium Paenisporosarcina sp. TG-14 in the extreme cold environment. Spo0A is a key response regulator of the phosphorelay system in the early stage of spore formation. The protein is composed of a regulatory N-terminal phospho-receiver domain and a DNA-binding C-terminal activator domain. We solved the three-dimensional structure of the unphosphorylated (inactive) form of the receiver domain of Spo0A (PaSpo0A-R) from Paenisporosarcina sp. TG-14. A structural comparison with phosphorylated (active form) Spo0A from Bacillus stearothermophilus (BsSpo0A) showed minor notable differences. A molecular dynamics study of a model of the active form and the crystal structures revealed significant differences in the α4 helix and the preceding loop region where phosphorylation occurs. Although an oligomerization study of PaSpo0A-R by analytical ultracentrifugation (AUC) has shown that the protein is in a monomeric state in solution, both crosslinking and crystal-packing analyses indicate the possibility of weak dimer formation by a previously undocumented mechanism. Collectively, these observations provide insight into the mechanism of phosphorylation-dependent activation unique to Spo0A.
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28
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Foster CA, West AH. Use of restrained molecular dynamics to predict the conformations of phosphorylated receiver domains in two-component signaling systems. Proteins 2016; 85:155-176. [PMID: 27802580 PMCID: PMC5242315 DOI: 10.1002/prot.25207] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 10/22/2016] [Accepted: 10/25/2016] [Indexed: 01/22/2023]
Abstract
Two‐component signaling (TCS) is the primary means by which bacteria, as well as certain plants and fungi, respond to external stimuli. Signal transduction involves stimulus‐dependent autophosphorylation of a sensor histidine kinase and phosphoryl transfer to the receiver domain of a downstream response regulator. Phosphorylation acts as an allosteric switch, inducing structural and functional changes in the pathway's components. Due to their transient nature, phosphorylated receiver domains are challenging to characterize structurally. In this work, we provide a methodology for simulating receiver domain phosphorylation to predict conformations that are nearly identical to experimental structures. Using restrained molecular dynamics, phosphorylated conformations of receiver domains can be reliably sampled on nanosecond timescales. These simulations also provide data on conformational dynamics that can be used to identify regions of functional significance related to phosphorylation. We first validated this approach on several well‐characterized receiver domains and then used it to compare the upstream and downstream components of the fungal Sln1 phosphorelay. Our results demonstrate that this technique provides structural insight, obtained in the absence of crystallographic or NMR information, regarding phosphorylation‐induced conformational changes in receiver domains that regulate the output of their associated signaling pathway. To our knowledge, this is the first time such a protocol has been described that can be broadly applied to TCS proteins for predictive purposes. Proteins 2016; 85:155–176. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Clay A Foster
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma
| | - Ann H West
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma
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29
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Qin R, Sang Y, Ren J, Zhang Q, Li S, Cui Z, Yao YF. The Bacterial Two-Hybrid System Uncovers the Involvement of Acetylation in Regulating of Lrp Activity in Salmonella Typhimurium. Front Microbiol 2016; 7:1864. [PMID: 27909434 PMCID: PMC5112231 DOI: 10.3389/fmicb.2016.01864] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/04/2016] [Indexed: 12/14/2022] Open
Abstract
N𝜀-lysine acetylation is an abundant and important Post-translational modification in bacteria. We used the bacterial two-hybrid system to screen the genome library of the Salmonella Typhimurium to identify potential proteins involved in acetyltransferase Pat - or deacetylase CobB-mediated acetylation. Then, the in vitro (de)acetylation assays were used to validate the potential targets, such as STM14_1074, NrdF, RhaR. Lrp, a leucine-responsive regulatory protein and global regulator, was shown to interact with Pat. We further demonstrate that Lrp could be acetylated by Pat and deacetylated by NAD+-dependent CobB in vitro. Specifically, the conserved lysine residue 36 (K36) in helix-turn-helix (HTH) DNA-binding domain of Lrp was acetylated. Acetylation of K36 impaired the function of Lrp through altering the affinity with the target promoter. The mutation of K36 in chromosome mimicking acetylation enhanced the transcriptional level of itself and attenuated the mRNA levels of Lrp-regulated genes including fimA, which was confirmed by yeast agglutination assay. These findings demonstrate that the acetylation regulates the DNA-binding activity of Lrp, suggesting that acetylation modification of transcription factors is a conserved regulatory manner to modulate gene expression in bacteria and eukaryotes.
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Affiliation(s)
- Ran Qin
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University Nanjing, China
| | - Yu Sang
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine Shanghai, China
| | - Jie Ren
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine Shanghai, China
| | - Qiufen Zhang
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine Shanghai, China
| | - Shuxian Li
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine Shanghai, China
| | - Zhongli Cui
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University Nanjing, China
| | - Yu-Feng Yao
- Laboratory of Bacterial Pathogenesis, Department of Microbiology and Immunology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of MedicineShanghai, China; Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of MedicineShanghai, China
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30
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Filippova EV, Wawrzak Z, Ruan J, Pshenychnyi S, Schultz RM, Wolfe AJ, Anderson WF. Crystal structure of nonphosphorylated receiver domain of the stress response regulator RcsB from Escherichia coli. Protein Sci 2016; 25:2216-2224. [PMID: 27670836 DOI: 10.1002/pro.3050] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/23/2016] [Accepted: 09/23/2016] [Indexed: 11/12/2022]
Abstract
RcsB, the transcription-associated response regulator of the Rcs phosphorelay two-component signal transduction system, activates cell stress responses associated with desiccation, cell wall biosynthesis, cell division, virulence, biofilm formation, and antibiotic resistance in enteric bacterial pathogens. RcsB belongs to the FixJ/NarL family of transcriptional regulators, which are characterized by a highly conserved C-terminal DNA-binding domain. The N-terminal domain of RcsB belongs to the family of two-component receiver domains. This receiver domain contains the phosphoacceptor site and participates in RcsB dimer formation; it also contributes to dimer formation with other transcription factor partners. Here, we describe the crystal structure of the Escherichia coli RcsB receiver domain in its nonphosphorylated state. The structure reveals important molecular details of phosphorylation-independent dimerization of RcsB and has implication for the formation of heterodimers.
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Affiliation(s)
- Ekaterina V Filippova
- Department of Biochemistry and Molecular Genetics, Center for Structural Genomics of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, Illinois, 60611
| | - Zdzislaw Wawrzak
- Life Science Collaborative Access Team, Synchrotron Research Center, Northwestern University, Argonne, Illinois, 60439
| | - Jiapeng Ruan
- Yale University School of Medicine, Department of Digestive Diseases, New Haven, CT 06510
| | - Sergii Pshenychnyi
- Recombinant Protein Production Core, Northwestern University, Chemistry of Life Processes Institute, Evanston, Illinois 60208
| | - Richard M Schultz
- Department of Microbiology and Immunology, Loyola University Chicago, Health Sciences Division, Stritch School of Medicine, Maywood, Illinois, 60153
| | - Alan J Wolfe
- Department of Microbiology and Immunology, Loyola University Chicago, Health Sciences Division, Stritch School of Medicine, Maywood, Illinois, 60153
| | - Wayne F Anderson
- Department of Biochemistry and Molecular Genetics, Center for Structural Genomics of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, Illinois, 60611
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31
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Hung YL, Jiang I, Lee YZ, Wen CK, Sue SC. NMR Study Reveals the Receiver Domain of Arabidopsis ETHYLENE RESPONSE1 Ethylene Receptor as an Atypical Type Response Regulator. PLoS One 2016; 11:e0160598. [PMID: 27486797 PMCID: PMC4972365 DOI: 10.1371/journal.pone.0160598] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 07/21/2016] [Indexed: 11/26/2022] Open
Abstract
The gaseous plant hormone ethylene, recognized by plant ethylene receptors, plays a pivotal role in various aspects of plant growth and development. ETHYLENE RESPONSE1 (ETR1) is an ethylene receptor isolated from Arabidopsis and has a structure characteristic of prokaryotic two-component histidine kinase (HK) and receiver domain (RD), where the RD structurally resembles bacteria response regulators (RRs). The ETR1 HK domain has autophosphorylation activity, and little is known if the HK can transfer the phosphoryl group to the RD for receptor signaling. Unveiling the correlation of the receptor structure and phosphorylation status would advance the studies towards the underlying mechanisms of ETR1 receptor signaling. In this study, using the nuclear magnetic resonance technique, our data suggested that the ETR1-RD is monomeric in solution and the rigid structure of the RD prevents the conserved aspartate residue phosphorylation. Comparing the backbone dynamics with other RRs, we propose that backbone flexibility is critical to the RR phosphorylation. Besides the limited flexibility, ETR1-RD has a unique γ loop conformation of opposite orientation, which makes ETR1-RD unfavorable for phosphorylation. These two features explain why ETR1-RD cannot be phosphorylated and is classified as an atypical type RR. As a control, phosphorylation of the ETR1-RD was also impaired when the sequence was swapped to the fragment of the bacterial typical type RR, CheY. Here, we suggest a molecule insight that the ETR1-RD already exists as an active formation and executes its function through binding with the downstream factors without phosphorylation.
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Affiliation(s)
- Yi-Lin Hung
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
- Instrumentation Center, National Tsing Hua University, Hsinchu, Taiwan
| | - Ingjye Jiang
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Yi-Zong Lee
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Chi-Kuang Wen
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Shih-Che Sue
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
- Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan
- * E-mail:
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The Response Regulator BfmR Is a Potential Drug Target for Acinetobacter baumannii. mSphere 2016; 1:mSphere00082-16. [PMID: 27303741 PMCID: PMC4888885 DOI: 10.1128/msphere.00082-16] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 04/12/2016] [Indexed: 11/24/2022] Open
Abstract
Increasing antibiotic resistance in bacteria, particularly Gram-negative bacilli, has significantly affected the ability of physicians to treat infections, with resultant increased morbidity, mortality, and health care costs. In fact, some strains of bacteria are resistant to all available antibiotics, such as Acinetobacter baumannii, which is the focus of this report. Therefore, the development of new antibiotics active against these resistant strains is urgently needed. In this study, BfmR is further validated as an intriguing target for a novel class of antibiotics. Successful inactivation of BfmR would confer the multiple benefits of a decreased ability of A. baumannii to survive in human body fluids, increased sensitivity to complement-mediated bactericidal activity and, importantly, increased sensitivity to other antibiotics. Structural studies support the potential for this “druggable” target, as they identify the potential for small-molecule binding at functionally relevant sites. Next-phase high-throughput screening studies utilizing BfmR are warranted. Identification and validation is the first phase of target-based antimicrobial development. BfmR (RstA), a response regulator in a two-component signal transduction system (TCS) in Acinetobacter baumannii, is an intriguing potential antimicrobial target. A unique characteristic of BfmR is that its inhibition would have the dual benefit of significantly decreasing in vivo survival and increasing sensitivity to selected antimicrobials. Studies on the clinically relevant strain AB307-0294 have shown BfmR to be essential in vivo. Here, we demonstrate that this phenotype in strains AB307-0294 and AB908 is mediated, in part, by enabling growth in human ascites fluid and serum. Further, BfmR conferred resistance to complement-mediated bactericidal activity that was independent of capsular polysaccharide. Importantly, BfmR also increased resistance to the clinically important antimicrobials meropenem and colistin. BfmR was highly conserved among A. baumannii strains. The crystal structure of the receiver domain of BfmR was determined, lending insight into putative ligand binding sites. This enabled an in silico ligand binding analysis and a blind docking strategy to assess use as a potential druggable target. Predicted binding hot spots exist at the homodimer interface and the phosphorylation site. These data support pursuing the next step in the development process, which includes determining the degree of inhibition needed to impact growth/survival and the development a BfmR activity assay amenable to high-throughput screening for the identification of inhibitors. Such agents would represent a new class of antimicrobials active against A. baumannii which could be active against other Gram-negative bacilli that possess a TCS with shared homology. IMPORTANCE Increasing antibiotic resistance in bacteria, particularly Gram-negative bacilli, has significantly affected the ability of physicians to treat infections, with resultant increased morbidity, mortality, and health care costs. In fact, some strains of bacteria are resistant to all available antibiotics, such as Acinetobacter baumannii, which is the focus of this report. Therefore, the development of new antibiotics active against these resistant strains is urgently needed. In this study, BfmR is further validated as an intriguing target for a novel class of antibiotics. Successful inactivation of BfmR would confer the multiple benefits of a decreased ability of A. baumannii to survive in human body fluids, increased sensitivity to complement-mediated bactericidal activity and, importantly, increased sensitivity to other antibiotics. Structural studies support the potential for this “druggable” target, as they identify the potential for small-molecule binding at functionally relevant sites. Next-phase high-throughput screening studies utilizing BfmR are warranted.
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He X, Wang L, Wang S. Structural basis of DNA sequence recognition by the response regulator PhoP in Mycobacterium tuberculosis. Sci Rep 2016; 6:24442. [PMID: 27079268 PMCID: PMC4832192 DOI: 10.1038/srep24442] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/30/2016] [Indexed: 01/20/2023] Open
Abstract
The transcriptional regulator PhoP is an essential virulence factor in Mycobacterium tuberculosis, and it presents a target for the development of new anti-tuberculosis drugs and attenuated tuberculosis vaccine strains. PhoP binds to DNA as a highly cooperative dimer by recognizing direct repeats of 7-bp motifs with a 4-bp spacer. To elucidate the PhoP-DNA binding mechanism, we determined the crystal structure of the PhoP-DNA complex. The structure revealed a tandem PhoP dimer that bound to the direct repeat. The surprising tandem arrangement of the receiver domains allowed the four domains of the PhoP dimer to form a compact structure, accounting for the strict requirement of a 4-bp spacer and the highly cooperative binding of the dimer. The PhoP-DNA interactions exclusively involved the effector domain. The sequence-recognition helix made contact with the bases of the 7-bp motif in the major groove, and the wing interacted with the adjacent minor groove. The structure provides a starting point for the elucidation of the mechanism by which PhoP regulates the virulence of M. tuberculosis and guides the design of screening platforms for PhoP inhibitors.
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Affiliation(s)
- Xiaoyuan He
- Department of Biochemistry &Molecular Biology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814, USA
| | - Liqin Wang
- Department of Biochemistry &Molecular Biology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814, USA
| | - Shuishu Wang
- Department of Biochemistry &Molecular Biology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814, USA
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Park AK, Lee JH, Chi YM, Park H. Structural characterization of the full-length response regulator spr1814 in complex with a phosphate analogue reveals a novel conformational plasticity of the linker region. Biochem Biophys Res Commun 2016; 473:625-9. [PMID: 27038544 DOI: 10.1016/j.bbrc.2016.03.144] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 03/29/2016] [Indexed: 01/04/2023]
Abstract
Spr1814 of Streptococcus pneumoniae is a response regulator (RR) that belongs to the NarL/FixJ subfamily and has a four-helix helix-turn-helix DNA-binding domain. Here, the X-ray crystal structure of the full-length spr1814 in complex with a phosphate analogue beryllium fluoride (BeF3(-)) was determined at 2.0 Å. This allows for a structural comparison with the previously reported full-length unphosphorylated spr1814. The phosphorylation of conserved aspartic acid residue of N-terminal receiver domain triggers a structural perturbation at the α4-β5-α5 interface, leading to the domain reorganization of spr1814, and this is achieved by a rotational change in the C-terminal DNA-binding domain.
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Affiliation(s)
- Ae Kyung Park
- Division of Biotechnology, College of Life Sciences, Korea University, Seoul 136-713, South Korea; Division of Polar Life Sciences, Korea Polar Research Institute, Yeonsu-gu, Incheon 406-840, South Korea
| | - Jeong Hye Lee
- Division of Biotechnology, College of Life Sciences, Korea University, Seoul 136-713, South Korea
| | - Young Min Chi
- Division of Biotechnology, College of Life Sciences, Korea University, Seoul 136-713, South Korea.
| | - Hyun Park
- Division of Polar Life Sciences, Korea Polar Research Institute, Yeonsu-gu, Incheon 406-840, South Korea.
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Acetylation of Lysine 201 Inhibits the DNA-Binding Ability of PhoP to Regulate Salmonella Virulence. PLoS Pathog 2016; 12:e1005458. [PMID: 26943369 PMCID: PMC4778762 DOI: 10.1371/journal.ppat.1005458] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 01/25/2016] [Indexed: 12/21/2022] Open
Abstract
The two-component system PhoP-PhoQ is highly conserved in bacteria and regulates virulence in response to various signals for bacteria within the mammalian host. Here, we demonstrate that PhoP could be acetylated by Pat and deacetylated by deacetylase CobB enzymatically in vitro and in vivo in Salmonella Typhimurium. Specifically, the conserved lysine residue 201(K201) in winged helix-turn-helix motif at C-terminal DNA-binding domain of PhoP could be acetylated, and its acetylation level decreases dramatically when bacteria encounter low magnesium, acid stress or phagocytosis of macrophages. PhoP has a decreased acetylation and increased DNA-binding ability in the deletion mutant of pat. However, acetylation of K201 does not counteract PhoP phosphorylation, which is essential for PhoP activity. In addition, acetylation of K201 (mimicked by glutamine substitute) in S. Typhimurium causes significantly attenuated intestinal inflammation as well as systemic infection in mouse model, suggesting that deacetylation of PhoP K201 is essential for Salmonella pathogenesis. Therefore, we propose that the reversible acetylation of PhoP K201 may ensure Salmonella promptly respond to different stresses in host cells. These findings suggest that reversible lysine acetylation in the DNA-binding domain, as a novel regulatory mechanism of gene expression, is involved in bacterial virulence across microorganisms.
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36
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Abstract
This review reviews the properties and regulation of the Salmonella enterica serovar Typhimurium and Escherichia coli transporters that mediate Mg2+ influx: CorA and the Mgt P-type ATPases. In addition, potential Mg2+ regulation of transcription and translation, largely via the PhoPQ two component system, is discussed. CorA proteins are a unique class of transporters and are widespread in the Bacteria and Archaea, with rather distant but functional homologs in eukaryotes. The Mgt transporters are highly homologous to other P-type ATPases but are more closely related to the eukaryotic H+ and Ca2+ ATPases than to most prokaryotic ATPases. Hundreds of homologs of CorA are currently known from genomic sequencing. In contrast, only when extracellular and possibly intracellular Mg2+ levels fall significantly is the expression of mgtA and mgtB induced. Topology studies using blaM and lacZ fusions initially indicated that the Salmonella serovar Typhimurium CorA contained three transmembrane (TM) segments; however, subsequent data obtained using a variety of approaches showed that the CorA superfamily of proteins have only two TMs at the extreme C terminus. PhoP-PhoQ is a two-component system consisting of PhoQ, the sensor/receptor histidine kinase, and PhoP, the response regulator/transcriptional activator. The expression of both mgtA and mgtCB in either E. coli or Salmonella serovar Typhimurium is markedly induced in a PhoPQ-dependent manner by low concentrations of Mg2+ in the medium. phoP and phoQ form an operon with two promoters in both E. coli and Salmonella serovar Typhimurium.
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37
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Fan X, Zhang X, Zhu Y, Niu L, Teng M, Sun B, Li X. Structure of the DNA-binding domain of the response regulator SaeR fromStaphylococcus aureus. ACTA ACUST UNITED AC 2015; 71:1768-76. [DOI: 10.1107/s1399004715010287] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 05/28/2015] [Indexed: 01/01/2023]
Abstract
The SaeR/S two-component regulatory system is essential for controlling the expression of many virulence factors inStaphylococcus aureus. SaeR, a member of the OmpR/PhoB family, is a response regulator with an N-terminal regulatory domain and a C-terminal DNA-binding domain. In order to elucidate how SaeR binds to the promoter regions of target genes, the crystal structure of the DNA-binding domain of SaeR (SaeRDBD) was solved at 2.5 Å resolution. The structure reveals that SaeRDBDexists as a monomer and has the canonical winged helix–turn–helix module. EMSA experiments suggested that full-length SaeR can bind to the P1 promoter and that the binding affinity is higher than that of its C-terminal DNA-binding domain. Five key residues on the winged helix–turn–helix module were verified to be important for binding to the P1 promoterin vitroand for the physiological function of SaeRin vivo.
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Ahmad A, Cai Y, Chen X, Shuai J, Han A. Conformational Dynamics of Response Regulator RegX3 from Mycobacterium tuberculosis. PLoS One 2015. [PMID: 26201027 PMCID: PMC4511772 DOI: 10.1371/journal.pone.0133389] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Two-component signal transduction systems (TCS) are vital for adaptive responses to various environmental stresses in bacteria, fungi and even plants. A TCS typically comprises of a sensor histidine kinase (SK) with its cognate response regulator (RR), which often has two domains—N terminal receiver domain (RD) and C terminal effector domain (ED). The histidine kinase phosphorylates the RD to activate the ED by promoting dimerization. However, despite significant progress on structural studies, how RR transmits activation signal from RD to ED remains elusive. Here we analyzed active to inactive transition process of OmpR/PhoB family using an active conformation of RegX3 from Mycobacterium tuberculosis as a model system by computational approaches. An inactive state of RegX3 generated from 150 ns molecular dynamic simulation has rotameric conformations of Thr79 and Tyr98 that are generally conserved in inactive RRs. Arg81 in loop β4α4 acts synergistically with loop β1α1 to change its interaction partners during active to inactive transition, potentially leading to the N-terminal movement of RegX3 helix α1. Global conformational dynamics of RegX3 is mainly dependent on α4β5 region, in particular seven ‘hot-spot’ residues (Tyr98 to Ser104), adjacent to which several coevolved residues at dimeric interface, including Ile76-Asp96, Asp97-Arg111 and Glu24-Arg113 pairs, are critical for signal transduction. Taken together, our computational analyses suggest a molecular linkage between Asp phosphorylation, proximal loops and α4β5α5 dimeric interface during RR active to inactive state transition, which is not often evidently defined from static crystal structures.
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Affiliation(s)
- Ashfaq Ahmad
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiangan, Xiamen, China
| | - Yongfei Cai
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiangan, Xiamen, China
| | - Xingqiang Chen
- Department of Physics, Xiamen University, Siming, Xiamen, China
| | - Jianwei Shuai
- Department of Physics, Xiamen University, Siming, Xiamen, China
| | - Aidong Han
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiangan, Xiamen, China
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Ocasio VJ, Corrêa F, Gardner KH. Ligand-induced folding of a two-component signaling receiver domain. Biochemistry 2015; 54:1353-63. [PMID: 25629646 DOI: 10.1021/bi501143b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
To survive and adapt to environmental changes, bacteria commonly use two-component signaling systems. Minimally, these pathways use histidine kinases (HKs) to detect environmental signals, harnessing these to control phosphorylation levels of receiver (REC) domains of downstream response regulators that convert this signal into physiological responses. Studies of several prototypical REC domains suggest that phosphorylation shifts these proteins between inactive and active structures that are globally similar and well-folded. However, it is unclear how globally these findings hold within REC domains in general, particularly when they are considered within full-length proteins. Here, we present EL_LovR, a full-length REC-only protein that is phosphorylated in response to blue light in the marine α-proteobacterium, Erythrobacter litoralis HTCC2594. Notably, EL_LovR is similar to comparable REC-only proteins used in bacterial general stress responses, where genetic evidence suggests that their potent phosphatase activity is important to shut off such systems. Size exclusion chromatography, light scattering, and solution NMR experiments show that EL_LovR is monomeric and unfolded in solution under conditions routinely used for other REC structure determinations. Addition of Mg(2+) and phosphorylation induce progressively greater degrees of tertiary structure stabilization, with the solution structure of the fully activated EL_LovR adopting the canonical receiver domain fold. Parallel functional assays show that EL_LovR has a fast dephosphorylation rate, consistent with its proposed function as a phosphate sink that depletes the HK phosphoryl group, promoting the phosphatase activity of this enzyme. Our findings demonstrate that EL_LovR undergoes substantial ligand-dependent conformational changes that have not been reported for other RRs, expanding the scope of conformational changes and regulation used by REC domains, critical components of bacterial signaling systems.
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Affiliation(s)
- Victor J Ocasio
- Departments of Biophysics and Biochemistry, UT Southwestern Medical Center , Dallas, Texas 75390-8816, United States
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40
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He X, Wang S. DNA consensus sequence motif for binding response regulator PhoP, a virulence regulator of Mycobacterium tuberculosis. Biochemistry 2014; 53:8008-20. [PMID: 25434965 PMCID: PMC4283936 DOI: 10.1021/bi501019u] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
![]()
Tuberculosis has reemerged as a serious
threat to human health
because of the increasing prevalence of drug-resistant strains and
synergetic infection with HIV, prompting an urgent need for new and
more efficient treatments. The PhoP–PhoR two-component system
of Mycobacterium tuberculosis plays an important
role in the virulence of the pathogen and thus represents a potential
drug target. To study the mechanism of gene transcription regulation
by response regulator PhoP, we identified a high-affinity DNA sequence
for PhoP binding using systematic evolution of ligands by exponential
enrichment. The sequence contains a direct repeat of two 7 bp motifs
separated by a 4 bp spacer, TCACAGC(N4)TCACAGC. The specificity
of the direct-repeat sequence for PhoP binding was confirmed by isothermal
titration calorimetry and electrophoretic mobility shift assays. PhoP
binds to the direct repeat as a dimer in a highly cooperative manner.
We found many genes previously identified to be regulated by PhoP
that contain the direct-repeat motif in their promoter sequences.
Synthetic DNA fragments at the putative promoter-binding sites bind
PhoP with variable affinity, which is related to the number of mismatches
in the 7 bp motifs, the positions of the mismatches, and the spacer
and flanking sequences. Phosphorylation of PhoP increases the affinity
but does not change the specificity of DNA binding. Overall, our results
confirm the direct-repeat sequence as the consensus motif for PhoP
binding and thus pave the way for identification of PhoP directly
regulated genes in different mycobacterial genomes.
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Affiliation(s)
- Xiaoyuan He
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences , Bethesda, Maryland 20814, United States
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41
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Allosteric activation of bacterial response regulators: the role of the cognate histidine kinase beyond phosphorylation. mBio 2014; 5:e02105. [PMID: 25406381 PMCID: PMC4251995 DOI: 10.1128/mbio.02105-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Response regulators are proteins that undergo transient phosphorylation, connecting specific signals to adaptive responses. Remarkably, the molecular mechanism of response regulator activation remains elusive, largely because of the scarcity of structural data on multidomain response regulators and histidine kinase/response regulator complexes. We now address this question by using a combination of crystallographic data and functional analyses in vitro and in vivo, studying DesR and its cognate sensor kinase DesK, a two-component system that controls membrane fluidity in Bacillus subtilis. We establish that phosphorylation of the receiver domain of DesR is allosterically coupled to two distinct exposed surfaces of the protein, controlling noncanonical dimerization/tetramerization, cooperative activation, and DesK binding. One of these surfaces is critical for both homodimerization- and kinase-triggered allosteric activations. Moreover, DesK induces a phosphorylation-independent activation of DesR in vivo, uncovering a novel and stringent level of specificity among kinases and regulators. Our results support a model that helps to explain how response regulators restrict phosphorylation by small-molecule phosphoryl donors, as well as cross talk with noncognate sensors. The ability to sense and respond to environmental variations is an essential property for cell survival. Two-component systems mediate key signaling pathways that allow bacteria to integrate extra- or intracellular signals. Here we focus on the DesK/DesR system, which acts as a molecular thermometer in B. subtilis, regulating the cell membrane’s fluidity. Using a combination of complementary approaches, including determination of the crystal structures of active and inactive forms of the response regulator DesR, we unveil novel molecular mechanisms of DesR’s activation switch. In particular, we show that the association of the cognate histidine kinase DesK triggers DesR activation beyond the transfer of the phosphoryl group. On the basis of sequence and structural analyses of other two-component systems, this activation mechanism appears to be used in a wide range of sensory systems, contributing a further level of specificity control among different signaling pathways.
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42
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Li YC, Chang CK, Chang CF, Cheng YH, Fang PJ, Yu T, Chen SC, Li YC, Hsiao CD, Huang TH. Structural dynamics of the two-component response regulator RstA in recognition of promoter DNA element. Nucleic Acids Res 2014; 42:8777-88. [PMID: 24990372 PMCID: PMC4117788 DOI: 10.1093/nar/gku572] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The RstA/RstB system is a bacterial two-component regulatory system consisting of the membrane sensor, RstB and its cognate response regulator (RR) RstA. The RstA of Klebsiella pneumoniae (kpRstA) consists of an N-terminal receiver domain (RD, residues 1-119) and a C-terminal DNA-binding domain (DBD, residues 130-236). Phosphorylation of kpRstA induces dimerization, which allows two kpRstA DBDs to bind to a tandem repeat, called the RstA box, and regulate the expression of downstream genes. Here we report the solution and crystal structures of the free kpRstA RD, DBD and DBD/RstA box DNA complex. The structure of the kpRstA DBD/RstA box complex suggests that the two protomers interact with the RstA box in an asymmetric fashion. Equilibrium binding studies further reveal that the two protomers within the kpRstA dimer bind to the RstA box in a sequential manner. Taken together, our results suggest a binding model where dimerization of the kpRstA RDs provides the platform to allow the first kpRstA DBD protomer to anchor protein-DNA interaction, whereas the second protomer plays a key role in ensuring correct recognition of the RstA box.
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Affiliation(s)
- Yi-Chuan Li
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan, ROC Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Chung-ke Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Chi-Fon Chang
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Ya-Hsin Cheng
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Pei-Ju Fang
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Tsunai Yu
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Sheng-Chia Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Yi-Ching Li
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Chwan-Deng Hsiao
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Tai-huang Huang
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan, ROC Genomics Research Center, Academia Sinica, Taipei 115, Taiwan, ROC Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan, ROC
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43
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Dual-site phosphorylation of the control of virulence regulator impacts group a streptococcal global gene expression and pathogenesis. PLoS Pathog 2014; 10:e1004088. [PMID: 24788524 PMCID: PMC4006921 DOI: 10.1371/journal.ppat.1004088] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 03/10/2014] [Indexed: 11/20/2022] Open
Abstract
Phosphorylation relays are a major mechanism by which bacteria alter transcription in response to environmental signals, but understanding of the functional consequences of bacterial response regulator phosphorylation is limited. We sought to characterize how phosphorylation of the control of virulence regulator (CovR) protein from the major human pathogen group A Streptococcus (GAS) influences GAS global gene expression and pathogenesis. CovR mainly serves to repress GAS virulence factor-encoding genes and has been shown to homodimerize following phosphorylation on aspartate-53 (D53) in vitro. We discovered that CovR is phosphorylated in vivo and that such phosphorylation is partially heat-stable, suggesting additional phosphorylation at non-aspartate residues. Using mass spectroscopy along with targeted mutagenesis, we identified threonine-65 (T65) as an additional CovR phosphorylation site under control of the serine/threonine kinase (Stk). Phosphorylation on T65, as mimicked by the recombinant CovR T65E variant, abolished in vitro CovR D53 phosphorylation. Similarly, isoallelic GAS strains that were either unable to be phosphorylated at D53 (CovR-D53A) or had functional constitutive phosphorylation at T65 (CovR-T65E) had essentially an identical gene repression profile to each other and to a CovR-inactivated strain. However, the CovR-D53A and CovR-T65E isoallelic strains retained the ability to positively influence gene expression that was abolished in the CovR-inactivated strain. Consistent with these observations, the CovR-D53A and CovR-T65E strains were hypervirulent compared to the CovR-inactivated strain in a mouse model of invasive GAS disease. Surprisingly, an isoalleic strain unable to be phosphorylated at CovR T65 (CovR-T65A) was hypervirulent compared to the wild-type strain, as auto-regulation of covR gene expression resulted in lower covR gene transcript and CovR protein levels in the CovR-T65A strain. Taken together, these data establish that CovR is phosphorylated in vivo and elucidate how the complex interplay between CovR D53 activating phosphorylation, T65 inhibiting phosphorylation, and auto-regulation impacts streptococcal host-pathogen interaction. Group A Streptococcus (GAS) causes a variety of human diseases ranging from mild throat infections to deadly invasive infections. The capacity of GAS to cause infections at such diverse locations is dependent on its ability to precisely control the production of a broad variety of virulence factors. The control of virulence regulator (CovR) is a master regulator of GAS genes encoding virulence factors. It is known that CovR can be phosphorylated on aspartate-53 in vitro and that such phosphorylation increases its regulatory activity, but what additional factors influence CovR-mediated gene expression have not been established. Herein we show for the first time that CovR is phosphorylated in vivo and that phosphorylation of CovR on threonine-65 by the threonine/serine kinase Stk prevents aspartate-53 phosphorylation, thereby decreasing CovR regulatory activity. Further, while CovR-mediated gene repression is highly dependent on aspartate-53 phosphorylation, CovR-mediated gene activation proceeds via a phosphorylation-independent mechanism. Modifications in CovR phosphorylation sites significantly affected the expression of GAS virulence factors during infection and markedly altered the ability of GAS to cause disease in mice. These data establish that multiple inter-related pathways converge to influence CovR phosphorylation, thereby providing new insight into the complex regulatory network used by GAS during infection.
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44
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Narayanan A, Kumar S, Evrard AN, Paul LN, Yernool DA. An asymmetric heterodomain interface stabilizes a response regulator-DNA complex. Nat Commun 2014; 5:3282. [PMID: 24526190 PMCID: PMC4399498 DOI: 10.1038/ncomms4282] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 01/18/2014] [Indexed: 01/08/2023] Open
Abstract
Two-component signal transduction systems consist of pairs of histidine kinases and response regulators, which mediate adaptive responses to environmental cues. Most activated response regulators regulate transcription by binding tightly to promoter DNA via a phosphorylation-triggered inactive-to-active transition. The molecular basis for formation of stable response regulator-DNA complexes that precede the assembly of RNA polymerases is unclear. Here, we present structures of DNA complexed with the response regulator KdpE, a member of the OmpR/PhoB family. The distinctively asymmetric complex in an active-like conformation reveals a unique intramolecular interface between the receiver domain (RD) and the DNA-binding domain (DBD) of only one of the two response regulators in the complex. Structure-function studies show that this RD-DBD interface is necessary to form stable complexes that support gene expression. The conservation of sequence and structure suggests that these findings extend to a large group of response regulators that act as transcription factors.
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Affiliation(s)
- Anoop Narayanan
- 1] Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, Indiana 47907, USA [2]
| | - Shivesh Kumar
- 1] Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, Indiana 47907, USA [2] [3]
| | - Amanda N Evrard
- Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, Indiana 47907, USA
| | - Lake N Paul
- Bindley Bioscience Center, Purdue University, 1203 West State Street, West Lafayette, Indiana 47907, USA
| | - Dinesh A Yernool
- 1] Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, Indiana 47907, USA [2] Bindley Bioscience Center, Purdue University, 1203 West State Street, West Lafayette, Indiana 47907, USA
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45
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Luo SC, Lou YC, Rajasekaran M, Chang YW, Hsiao CD, Chen C. Structural basis of a physical blockage mechanism for the interaction of response regulator PmrA with connector protein PmrD from Klebsiella pneumoniae. J Biol Chem 2013; 288:25551-25561. [PMID: 23861396 PMCID: PMC3757216 DOI: 10.1074/jbc.m113.481978] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In bacteria, the two-component system is the most prevalent for sensing and transducing environmental signals into the cell. The PmrA-PmrB two-component system, responsible for sensing external stimuli of high Fe(3+) and mild acidic conditions, can control the genes involved in lipopolysaccharide modification and polymyxin resistance in pathogens. In Klebsiella pneumoniae, the small basic connector protein PmrD protects phospho-PmrA and prolongs the expression of PmrA-activated genes. We previously determined the phospho-PmrA recognition mode of PmrD. However, how PmrA interacts with PmrD and prevents its dephosphorylation remains unknown. To address this question, we solved the x-ray crystal structure of the N-terminal receiver domain of BeF3(-)-activated PmrA (PmrA(N)) at 1.70 Å. With this structure, we applied the data-driven docking method based on NMR chemical shift perturbation to generate the complex model of PmrD-PmrA(N), which was further validated by site-directed spin labeling experiments. In the complex model, PmrD may act as a blockade to prevent phosphatase from contacting with the phosphorylation site on PmrA.
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Affiliation(s)
| | | | | | - Yi-Wei Chang
- Molecular Biology, Academia Sinica, Taipei 115, Taiwan and
| | | | - Chinpan Chen
- From the Institutes of Biomedical Sciences and ,Agricultural Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan, To whom correspondence should be addressed: Institute of Biomedical Sciences, Academia Sinica, 128 Academia Rd., Section 2, Taipei 115, Taiwan. Tel.: 886-2-2652-3035; Fax: 886-2-2788-7641; E-mail:
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46
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The Escherichia coli phosphotyrosine proteome relates to core pathways and virulence. PLoS Pathog 2013. [PMID: 23785281 DOI: 10.1371/journal.ppat.1003403.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
While phosphotyrosine modification is an established regulatory mechanism in eukaryotes, it is less well characterized in bacteria due to low prevalence. To gain insight into the extent and biological importance of tyrosine phosphorylation in Escherichia coli, we used immunoaffinity-based phosphotyrosine peptide enrichment combined with high resolution mass spectrometry analysis to comprehensively identify tyrosine phosphorylated proteins and accurately map phosphotyrosine sites. We identified a total of 512 unique phosphotyrosine sites on 342 proteins in E. coli K12 and the human pathogen enterohemorrhagic E. coli (EHEC) O157:H7, representing the largest phosphotyrosine proteome reported to date in bacteria. This large number of tyrosine phosphorylation sites allowed us to define five phosphotyrosine site motifs. Tyrosine phosphorylated proteins belong to various functional classes such as metabolism, gene expression and virulence. We demonstrate for the first time that proteins of a type III secretion system (T3SS), required for the attaching and effacing (A/E) lesion phenotype characteristic for intestinal colonization by certain EHEC strains, are tyrosine phosphorylated by bacterial kinases. Yet, A/E lesion and metabolic phenotypes were unaffected by the mutation of the two currently known tyrosine kinases, Etk and Wzc. Substantial residual tyrosine phosphorylation present in an etk wzc double mutant strongly indicated the presence of hitherto unknown tyrosine kinases in E. coli. We assess the functional importance of tyrosine phosphorylation and demonstrate that the phosphorylated tyrosine residue of the regulator SspA positively affects expression and secretion of T3SS proteins and formation of A/E lesions. Altogether, our study reveals that tyrosine phosphorylation in bacteria is more prevalent than previously recognized, and suggests the involvement of phosphotyrosine-mediated signaling in a broad range of cellular functions and virulence.
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47
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Hansen AM, Chaerkady R, Sharma J, Díaz-Mejía JJ, Tyagi N, Renuse S, Jacob HKC, Pinto SM, Sahasrabuddhe NA, Kim MS, Delanghe B, Srinivasan N, Emili A, Kaper JB, Pandey A. The Escherichia coli phosphotyrosine proteome relates to core pathways and virulence. PLoS Pathog 2013; 9:e1003403. [PMID: 23785281 PMCID: PMC3681748 DOI: 10.1371/journal.ppat.1003403] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 04/22/2013] [Indexed: 01/31/2023] Open
Abstract
While phosphotyrosine modification is an established regulatory mechanism in eukaryotes, it is less well characterized in bacteria due to low prevalence. To gain insight into the extent and biological importance of tyrosine phosphorylation in Escherichia coli, we used immunoaffinity-based phosphotyrosine peptide enrichment combined with high resolution mass spectrometry analysis to comprehensively identify tyrosine phosphorylated proteins and accurately map phosphotyrosine sites. We identified a total of 512 unique phosphotyrosine sites on 342 proteins in E. coli K12 and the human pathogen enterohemorrhagic E. coli (EHEC) O157:H7, representing the largest phosphotyrosine proteome reported to date in bacteria. This large number of tyrosine phosphorylation sites allowed us to define five phosphotyrosine site motifs. Tyrosine phosphorylated proteins belong to various functional classes such as metabolism, gene expression and virulence. We demonstrate for the first time that proteins of a type III secretion system (T3SS), required for the attaching and effacing (A/E) lesion phenotype characteristic for intestinal colonization by certain EHEC strains, are tyrosine phosphorylated by bacterial kinases. Yet, A/E lesion and metabolic phenotypes were unaffected by the mutation of the two currently known tyrosine kinases, Etk and Wzc. Substantial residual tyrosine phosphorylation present in an etk wzc double mutant strongly indicated the presence of hitherto unknown tyrosine kinases in E. coli. We assess the functional importance of tyrosine phosphorylation and demonstrate that the phosphorylated tyrosine residue of the regulator SspA positively affects expression and secretion of T3SS proteins and formation of A/E lesions. Altogether, our study reveals that tyrosine phosphorylation in bacteria is more prevalent than previously recognized, and suggests the involvement of phosphotyrosine-mediated signaling in a broad range of cellular functions and virulence. While phosphotyrosine modification is established in eukaryote cell signaling, it is less characterized in bacteria. Despite that deletion of bacterial tyrosine kinases is known to affect various cellular functions and virulence of bacterial pathogens, few phosphotyrosine proteins are currently known. To gain insight into the extent and biological function of tyrosine phosphorylation in E. coli, we carried out an in-depth phosphotyrosine protein profiling using a mass spectrometry-based proteomics approach. Our study on E. coli K12 and the human pathogen enterohemorrhagic E. coli (EHEC) O157:H7, which is a common cause of food-borne outbreaks of diarrhea, hemorrhagic colitis and hemolytic uremic syndrome, reveal that tyrosine phosphorylation is far more prevalent than previously recognized. Target proteins are involved in a broad range of cellular functions and virulence. Proteins of the type III secretion system (T3SS), required for the attaching and effacing lesion phenotype characteristic for intestinal colonization by EHEC, are tyrosine phosphorylated. The expression of these T3SS proteins and A/E lesion formation is affected by a tyrosine phosphorylated residue on the regulator SspA. Also, our data indicates the presence of hitherto unknown E. coli tyrosine kinases. Overall, tyrosine phosphorylation seems to be involved in controlling cellular core processes and virulence of bacteria.
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Affiliation(s)
- Anne-Marie Hansen
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Raghothama Chaerkady
- Institute of Bioinformatics, International Tech Park, Bangalore, India
- McKusick-Nathans Institute of Genetic Medicine and Department of Biological Chemistry, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Jyoti Sharma
- Institute of Bioinformatics, International Tech Park, Bangalore, India
- Manipal University, Manipal, India
| | - J. Javier Díaz-Mejía
- Banting and Best Department of Medical Research, Terrence Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada
- Department of Biology, Wilfrid Laurier University, Waterloo, Canada
| | - Nidhi Tyagi
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Santosh Renuse
- Institute of Bioinformatics, International Tech Park, Bangalore, India
- McKusick-Nathans Institute of Genetic Medicine and Department of Biological Chemistry, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Harrys K. C. Jacob
- Institute of Bioinformatics, International Tech Park, Bangalore, India
- McKusick-Nathans Institute of Genetic Medicine and Department of Biological Chemistry, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Sneha M. Pinto
- Institute of Bioinformatics, International Tech Park, Bangalore, India
- Manipal University, Manipal, India
| | - Nandini A. Sahasrabuddhe
- Institute of Bioinformatics, International Tech Park, Bangalore, India
- McKusick-Nathans Institute of Genetic Medicine and Department of Biological Chemistry, Johns Hopkins University, Baltimore, Maryland, United States of America
- Manipal University, Manipal, India
| | - Min-Sik Kim
- McKusick-Nathans Institute of Genetic Medicine and Department of Biological Chemistry, Johns Hopkins University, Baltimore, Maryland, United States of America
| | | | | | - Andrew Emili
- Department of Biology, Wilfrid Laurier University, Waterloo, Canada
| | - James B. Kaper
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (JBK); (AP)
| | - Akhilesh Pandey
- Institute of Bioinformatics, International Tech Park, Bangalore, India
- McKusick-Nathans Institute of Genetic Medicine and Department of Biological Chemistry, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Pathology and Oncology, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail: (JBK); (AP)
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48
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Barbieri CM, Wu T, Stock AM. Comprehensive analysis of OmpR phosphorylation, dimerization, and DNA binding supports a canonical model for activation. J Mol Biol 2013; 425:1612-26. [PMID: 23399542 DOI: 10.1016/j.jmb.2013.02.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 01/22/2013] [Accepted: 02/02/2013] [Indexed: 11/16/2022]
Abstract
The OmpR/PhoB family of response regulators (RRs) is the largest class of two-component system signal transduction proteins. Extensive biochemical and structural characterization of these transcription factors has provided insights into their activation and DNA-binding mechanisms. For the most part, OmpR/PhoB family proteins are thought to become activated through phosphorylation from their cognate histidine kinase partners, which in turn facilitates an allosteric change in the RR, enabling homodimerization and subsequently enhanced DNA binding. Incongruently, it has been suggested that OmpR, the eponymous member of this RR family, becomes activated via different mechanisms, whereby DNA binding plays a central role in facilitating dimerization and phosphorylation. Characterization of the rate and extent of the phosphorylation of OmpR and OmpR DNA-binding mutants following activation of the EnvZ/OmpR two-component system shows that DNA binding is not essential for phosphorylation of OmpR in vivo. In addition, detailed analyses of the energetics of DNA binding and dimerization of OmpR in both its unphosphorylated and phosphorylated state indicate that phosphorylation enhances OmpR dimerization and that this dimerization enhancement is the energetic driving force for phosphorylation-mediated regulation of OmpR-DNA binding. These findings suggest that OmpR phosphorylation-mediated activation follows the same paradigm as the other members of the OmpR/PhoB family of RRs in contrast to previously proposed models of OmpR activation.
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Affiliation(s)
- Christopher M Barbieri
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, 679 Hoes Lane West, Piscataway, NJ 08854, USA
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Micevski D, Dougan DA. Proteolytic regulation of stress response pathways in Escherichia coli. Subcell Biochem 2013; 66:105-28. [PMID: 23479439 DOI: 10.1007/978-94-007-5940-4_5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Maintaining correct cellular function is a fundamental biological process for all forms of life. A critical aspect of this process is the maintenance of protein homeostasis (proteostasis) in the cell, which is largely performed by a group of proteins, referred to as the protein quality control (PQC) network. This network of proteins, comprised of chaperones and proteases, is critical for maintaining proteostasis not only during favourable growth conditions, but also in response to stress. Indeed proteases play a crucial role in the clearance of unwanted proteins that accumulate during stress, but more importantly, in the activation of various different stress response pathways. In bacteria, the cells response to stress is usually orchestrated by a specific transcription factor (sigma factor). In Escherichia coli there are seven different sigma factors, each of which responds to a particular stress, resulting in the rapid expression of a specific set of genes. The cellular concentration of each transcription factor is tightly controlled, at the level of transcription, translation and protein stability. Here we will focus on the proteolytic regulation of two sigma factors (σ(32) and σ(S)), which control the heat and general stress response pathways, respectively. This review will also briefly discuss the role proteolytic systems play in the clearance of unwanted proteins that accumulate during stress.
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Affiliation(s)
- Dimce Micevski
- Department of Biochemistry, La Trobe Institute for Molecular Science (LIMS), La Trobe University, Melbourne, 3086, Australia
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Gu W, Wang X, Qiu H, Luo X, Xiao D, Xiao Y, Tang L, Kan B, Jing H. Comparative antigenic proteins and proteomics of pathogenic Yersinia enterocolitica bio-serotypes 1B/O: 8 and 2/O: 9 cultured at 25°C and 37°C. Microbiol Immunol 2012; 56:583-94. [DOI: 10.1111/j.1348-0421.2012.00478.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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