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Ren L, Shen D, Liu C, Ding Y. Protein Tyrosine and Serine/Threonine Phosphorylation in Oral Bacterial Dysbiosis and Bacteria-Host Interaction. Front Cell Infect Microbiol 2022; 11:814659. [PMID: 35087767 PMCID: PMC8787120 DOI: 10.3389/fcimb.2021.814659] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 12/13/2021] [Indexed: 02/05/2023] Open
Abstract
The human oral cavity harbors approximately 1,000 microbial species, and dysbiosis of the microflora and imbalanced microbiota-host interactions drive many oral diseases, such as dental caries and periodontal disease. Oral microbiota homeostasis is critical for systemic health. Over the last two decades, bacterial protein phosphorylation systems have been extensively studied, providing mounting evidence of the pivotal role of tyrosine and serine/threonine phosphorylation in oral bacterial dysbiosis and bacteria-host interactions. Ongoing investigations aim to discover novel kinases and phosphatases and to understand the mechanism by which these phosphorylation events regulate the pathogenicity of oral bacteria. Here, we summarize the structures of bacterial tyrosine and serine/threonine kinases and phosphatases and discuss the roles of tyrosine and serine/threonine phosphorylation systems in Porphyromonas gingivalis and Streptococcus mutans, emphasizing their involvement in bacterial metabolism and virulence, community development, and bacteria-host interactions.
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Affiliation(s)
- Liang Ren
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Daonan Shen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Chengcheng Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yi Ding
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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2
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Sande C, Whitfield C. Capsules and Extracellular Polysaccharides in Escherichia coli and Salmonella. EcoSal Plus 2021; 9:eESP00332020. [PMID: 34910576 PMCID: PMC11163842 DOI: 10.1128/ecosalplus.esp-0033-2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 10/26/2021] [Indexed: 12/16/2022]
Abstract
Escherichia coli and Salmonella isolates produce a range of different polysaccharide structures that play important roles in their biology. E. coli isolates often possess capsular polysaccharides (K antigens), which form a surface structural layer. These possess a wide range of repeat-unit structures. In contrast, only one capsular polymer (Vi antigen) is found in Salmonella, and it is confined to typhoidal serovars. In both genera, capsules are vital virulence determinants and are associated with the avoidance of host immune defenses. Some isolates of these species also produce a largely secreted exopolysaccharide called colanic acid as part of their complex Rcs-regulated phenotypes, but the precise function of this polysaccharide in microbial cell biology is not fully understood. E. coli isolates produce two additional secreted polysaccharides, bacterial cellulose and poly-N-acetylglucosamine, which play important roles in biofilm formation. Cellulose is also produced by Salmonella isolates, but the genes for poly-N-acetylglucosamine synthesis appear to have been lost during its evolution toward enhanced virulence. Here, we discuss the structures, functions, relationships, and sophisticated assembly mechanisms for these important biopolymers.
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Affiliation(s)
- Caitlin Sande
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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3
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Yang Y, Liu J, Clarke BR, Seidel L, Bolla JR, Ward PN, Zhang P, Robinson CV, Whitfield C, Naismith JH. The molecular basis of regulation of bacterial capsule assembly by Wzc. Nat Commun 2021; 12:4349. [PMID: 34272394 PMCID: PMC8285477 DOI: 10.1038/s41467-021-24652-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 06/29/2021] [Indexed: 01/06/2023] Open
Abstract
Bacterial extracellular polysaccharides (EPSs) play critical roles in virulence. Many bacteria assemble EPSs via a multi-protein "Wzx-Wzy" system, involving glycan polymerization at the outer face of the cytoplasmic/inner membrane. Gram-negative species couple polymerization with translocation across the periplasm and outer membrane and the master regulator of the system is the tyrosine autokinase, Wzc. This near atomic cryo-EM structure of dephosphorylated Wzc from E. coli shows an octameric assembly with a large central cavity formed by transmembrane helices. The tyrosine autokinase domain forms the cytoplasm region, while the periplasmic region contains small folded motifs and helical bundles. The helical bundles are essential for function, most likely through interaction with the outer membrane translocon, Wza. Autophosphorylation of the tyrosine-rich C-terminus of Wzc results in disassembly of the octamer into multiply phosphorylated monomers. We propose that the cycling between phosphorylated monomer and dephosphorylated octamer regulates glycan polymerization and translocation.
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Affiliation(s)
- Yun Yang
- Rosalind Franklin Institute, Harwell Campus, Harwell, UK.,Division of Structural Biology, The University of Oxford, Oxford, UK.,The Research Complex at Harwell, Harwell Campus, Harwell, UK
| | - Jiwei Liu
- Rosalind Franklin Institute, Harwell Campus, Harwell, UK.,Division of Structural Biology, The University of Oxford, Oxford, UK
| | - Bradley R Clarke
- Department of Molecular and Cellular Biology, The University of Guelph, Guelph, ON, Canada
| | - Laura Seidel
- Department of Molecular and Cellular Biology, The University of Guelph, Guelph, ON, Canada
| | - Jani R Bolla
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, South Parks Road, The University of Oxford, Oxford, UK.,The Kavli Institute for Nanoscience Discovery, Oxford, UK
| | - Philip N Ward
- Rosalind Franklin Institute, Harwell Campus, Harwell, UK.,Division of Structural Biology, The University of Oxford, Oxford, UK.,The Research Complex at Harwell, Harwell Campus, Harwell, UK
| | - Peijun Zhang
- Division of Structural Biology, The University of Oxford, Oxford, UK.,Electron Bio-Imaging Centre, Diamond Light Source, Harwell Science and Innovation Campus, Harwell, UK
| | - Carol V Robinson
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, South Parks Road, The University of Oxford, Oxford, UK.,The Kavli Institute for Nanoscience Discovery, Oxford, UK
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, The University of Guelph, Guelph, ON, Canada.
| | - James H Naismith
- Rosalind Franklin Institute, Harwell Campus, Harwell, UK. .,Division of Structural Biology, The University of Oxford, Oxford, UK. .,The Research Complex at Harwell, Harwell Campus, Harwell, UK.
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4
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Wang X, Ma Q. Wzb of Vibrio vulnificus represents a new group of low-molecular-weight protein tyrosine phosphatases with a unique insertion in the W-loop. J Biol Chem 2021; 296:100280. [PMID: 33450227 PMCID: PMC7948962 DOI: 10.1016/j.jbc.2021.100280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 12/28/2020] [Accepted: 01/08/2021] [Indexed: 12/23/2022] Open
Abstract
Protein tyrosine phosphorylation regulates the production of capsular polysaccharide, an essential virulence factor of the deadly pathogen Vibrio vulnificus. The process requires the protein tyrosine kinase Wzc and its cognate phosphatase Wzb, both of which are largely uncharacterized. Herein, we report the structures of Wzb of V. vulnificus (VvWzb) in free and ligand-bound forms. VvWzb belongs to the low-molecular-weight protein tyrosine phosphatase (LMWPTP) family. Interestingly, it contains an extra four-residue insertion in the W-loop, distinct from all known LMWPTPs. The W-loop of VvWzb protrudes from the protein body in the free structure, but undergoes significant conformational changes to fold toward the active site upon ligand binding. Deleting the four-residue insertion from the W-loop severely impaired the enzymatic activity of VvWzb, indicating its importance for optimal catalysis. However, mutating individual residues or even substituting the whole insertion with four alanine residues only modestly decreased the enzymatic activity, suggesting that the contribution of the insertion to catalysis is not determined by the sequence specificity. Furthermore, inserting the four residues into Escherichia coli Wzb at the corresponding position enhanced its activity as well, indicating that the four-residue insertion in the W-loop can act as a general activity enhancing element for other LMWPTPs. The novel W-loop type and phylogenetic analysis suggested that VvWzb and its homologs should be classified into a new group of LMWPTPs. Our study sheds new insight into the catalytic mechanism and structural diversity of the LMWPTP family and promotes the understanding of the protein tyrosine phosphorylation system in prokaryotes.
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Affiliation(s)
- Xin Wang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China; University of Chinese Academy of Sciences, Beijing, China
| | - Qingjun Ma
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China; University of Chinese Academy of Sciences, Beijing, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China.
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5
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Sánchez-Rodríguez R, González GM, Becerril-García MA, Treviño-Rangel RDJ, Marcos-Vilchis A, González-Pedrajo B, Valvano MA, Andrade A. The BPtpA protein from Burkholderia cenocepacia belongs to a new subclass of low molecular weight protein tyrosine phosphatases. Arch Biochem Biophys 2020; 681:108277. [PMID: 31978399 DOI: 10.1016/j.abb.2020.108277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/15/2020] [Accepted: 01/17/2020] [Indexed: 11/24/2022]
Abstract
Low molecular weight protein tyrosine phosphatases (LMW-PTP) are ubiquitous enzymes found across a spectrum of genera from prokaryotes to higher eukaryotes. LMW-PTP belong to the Cys-based PTP class II protein family. Here, we show that LMW-PTP can be categorized into two different groups, referred as class II subdivision I (class II.I) and subdivision II (class II.II). Using BPtpA from the opportunistic pathogen Burkholderia cenocepacia, as a representative member of the LMW-PTP class II.I, we demonstrated that four conserved residues (W47, H48, D80, and F81) are required for enzyme function. Guided by an in silico model of BPtpA, we show that the conserved residues at α3-helix (D80 and F81) contribute to protein stability, while the other conserved residues in the W-loop (W47 and H48) likely play a role in substrate recognition. Overall, our results provide new information on LMW-PTP protein family and establish B. cenocepacia as a suitable model to investigate how substrates are recognized and sorted by these proteins.
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Affiliation(s)
- Rebeca Sánchez-Rodríguez
- Universidad Autónoma de Nuevo León, Facultad de Medicina, Departamento de Microbiología. Monterrey, Nuevo León, 64460, Mexico
| | - Gloria M González
- Universidad Autónoma de Nuevo León, Facultad de Medicina, Departamento de Microbiología. Monterrey, Nuevo León, 64460, Mexico
| | - Miguel A Becerril-García
- Universidad Autónoma de Nuevo León, Facultad de Medicina, Departamento de Microbiología. Monterrey, Nuevo León, 64460, Mexico
| | - Rogelio de J Treviño-Rangel
- Universidad Autónoma de Nuevo León, Facultad de Medicina, Departamento de Microbiología. Monterrey, Nuevo León, 64460, Mexico
| | - Arely Marcos-Vilchis
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, 70-243, Mexico
| | - Bertha González-Pedrajo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, 70-243, Mexico
| | - Miguel A Valvano
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, BT9 7BL, United Kingdom
| | - Angel Andrade
- Universidad Autónoma de Nuevo León, Facultad de Medicina, Departamento de Microbiología. Monterrey, Nuevo León, 64460, Mexico.
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6
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Pereira SB, Santos M, Leite JP, Flores C, Eisfeld C, Büttel Z, Mota R, Rossi F, De Philippis R, Gales L, Morais‐Cabral JH, Tamagnini P. The role of the tyrosine kinase Wzc (Sll0923) and the phosphatase Wzb (Slr0328) in the production of extracellular polymeric substances (EPS) by Synechocystis PCC 6803. Microbiologyopen 2019; 8:e00753. [PMID: 30675753 PMCID: PMC6562117 DOI: 10.1002/mbo3.753] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 09/21/2018] [Accepted: 09/22/2018] [Indexed: 11/10/2022] Open
Abstract
Many cyanobacteria produce extracellular polymeric substances (EPS) mainly composed of heteropolysaccharides with unique characteristics that make them suitable for biotechnological applications. However, manipulation/optimization of EPS biosynthesis/characteristics is hindered by a poor understanding of the production pathways and the differences between bacterial species. In this work, genes putatively related to different pathways of cyanobacterial EPS polymerization, assembly, and export were targeted for deletion or truncation in the unicellular Synechocystis sp. PCC 6803. No evident phenotypic changes were observed for some mutants in genes occurring in multiple copies in Synechocystis genome, namely ∆wzy (∆sll0737), ∆wzx (∆sll5049), ∆kpsM (∆slr2107), and ∆kpsM∆wzy (∆slr2107∆sll0737), strongly suggesting functional redundancy. In contrast, Δwzc (Δsll0923) and Δwzb (Δslr0328) influenced both the amount and composition of the EPS, establishing that Wzc participates in the production of capsular (CPS) and released (RPS) polysaccharides, and Wzb affects RPS production. The structure of Wzb was solved (2.28 Å), revealing structural differences relative to other phosphatases involved in EPS production and suggesting a different substrate recognition mechanism. In addition, Wzc showed the ATPase and autokinase activities typical of bacterial tyrosine kinases. Most importantly, Wzb was able to dephosphorylate Wzc in vitro, suggesting that tyrosine phosphorylation/dephosphorylation plays a role in cyanobacterial EPS production.
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Affiliation(s)
- Sara B. Pereira
- i3S ‐ Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- IBMC ‐ Instituto de Biologia Molecular e CelularUniversidade do PortoPortoPortugal
| | - Marina Santos
- i3S ‐ Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- IBMC ‐ Instituto de Biologia Molecular e CelularUniversidade do PortoPortoPortugal
- ICBAS – Instituto de Ciências Biomédicas Abel SalazarPortoPortugal
| | - José P. Leite
- i3S ‐ Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- IBMC ‐ Instituto de Biologia Molecular e CelularUniversidade do PortoPortoPortugal
- ICBAS – Instituto de Ciências Biomédicas Abel SalazarPortoPortugal
| | - Carlos Flores
- i3S ‐ Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- IBMC ‐ Instituto de Biologia Molecular e CelularUniversidade do PortoPortoPortugal
- ICBAS – Instituto de Ciências Biomédicas Abel SalazarPortoPortugal
| | - Carina Eisfeld
- i3S ‐ Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- IBMC ‐ Instituto de Biologia Molecular e CelularUniversidade do PortoPortoPortugal
- Present address:
Department of Water ManagementDelft University of TechnologyDelftThe Netherlands
| | - Zsófia Büttel
- IBMC ‐ Instituto de Biologia Molecular e CelularUniversidade do PortoPortoPortugal
- Present address:
Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology InstituteUniversity of GroningenGroningenThe Netherlands
| | - Rita Mota
- i3S ‐ Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- IBMC ‐ Instituto de Biologia Molecular e CelularUniversidade do PortoPortoPortugal
| | - Federico Rossi
- Department of Agrifood Production and Environmental SciencesUniversity of FlorenceFlorenceItaly
| | - Roberto De Philippis
- Department of Agrifood Production and Environmental SciencesUniversity of FlorenceFlorenceItaly
| | - Luís Gales
- i3S ‐ Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- IBMC ‐ Instituto de Biologia Molecular e CelularUniversidade do PortoPortoPortugal
- ICBAS – Instituto de Ciências Biomédicas Abel SalazarPortoPortugal
| | - João H. Morais‐Cabral
- i3S ‐ Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- IBMC ‐ Instituto de Biologia Molecular e CelularUniversidade do PortoPortoPortugal
| | - Paula Tamagnini
- i3S ‐ Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- IBMC ‐ Instituto de Biologia Molecular e CelularUniversidade do PortoPortoPortugal
- Faculdade de Ciências, Departamento de BiologiaUniversidade do PortoPortoPortugal
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7
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Sachdeva S, Palur RV, Sudhakar KU, Rathinavelan T. E. coli Group 1 Capsular Polysaccharide Exportation Nanomachinary as a Plausible Antivirulence Target in the Perspective of Emerging Antimicrobial Resistance. Front Microbiol 2017; 8:70. [PMID: 28217109 PMCID: PMC5290995 DOI: 10.3389/fmicb.2017.00070] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 01/11/2017] [Indexed: 02/02/2023] Open
Abstract
Bacteria evolving resistance against the action of multiple drugs and its ability to disseminate the multidrug resistance trait(s) across various strains of the same bacteria or different bacterial species impose serious threat to public health. Evolution of such multidrug resistance is due to the fact that, most of the antibiotics target bacterial survival mechanisms which exert selective pressure on the bacteria and aids them to escape from the action of antibiotics. Nonetheless, targeting bacterial virulence strategies such as bacterial surface associated polysaccharides biosynthesis and their surface accumulation mechanisms may be an attractive strategy, as they impose less selective pressure on the bacteria. Capsular polysaccharide (CPS) or K-antigen that is located on the bacterial surface armors bacteria from host immune response. Thus, unencapsulating bacteria would be a good strategy for drug design, besides CPS itself being a good vaccine target, by interfering with CPS biosynthesis and surface assembly pathway. Gram-negative Escherichia coli uses Wzy-polymerase dependent (Groups 1 and 4) and ATP dependent (Groups 1 and 3) pathways for CPS production. Considering E. coli as a case in point, this review explains the structure and functional roles of proteins involved in Group 1 Wzy dependent CPS biosynthesis, surface expression and anchorage in relevance to drug and vaccine developments.
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Affiliation(s)
- Shivangi Sachdeva
- Department of Biotechnology, Indian Institute of Technology Hyderabad Kandi, India
| | - Raghuvamsi V Palur
- Department of Biotechnology, Indian Institute of Technology Hyderabad Kandi, India
| | - Karpagam U Sudhakar
- Department of Biotechnology, Indian Institute of Technology Hyderabad Kandi, India
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8
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Salomone-Stagni M, Musiani F, Benini S. Characterization and 1.57 Å resolution structure of the key fire blight phosphatase AmsI from Erwinia amylovora. Acta Crystallogr F Struct Biol Commun 2016; 72:903-910. [PMID: 27917839 PMCID: PMC5137468 DOI: 10.1107/s2053230x16018781] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 11/23/2016] [Indexed: 11/10/2022] Open
Abstract
AmsI is a low-molecular-weight protein tyrosine phosphatase that regulates the production of amylovoran in the Gram-negative bacterium Erwinia amylovora, a specific pathogen of rosaceous plants such as apple, pear and quince. Amylovoran is an exopolysaccharide that is necessary for successful infection. In order to shed light on AmsI, its structure was solved at 1.57 Å resolution at the same pH as its highest measured activity (pH 5.5). In the active site, a water molecule, bridging between the catalytic Arg15 and the reaction-product analogue sulfate, might be representative of the water molecule attacking the phospho-cysteine intermediate in the second step of the reaction mechanism.
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Affiliation(s)
- Marco Salomone-Stagni
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100 Bolzano, Italy
| | - Francesco Musiani
- Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, 40127 Bologna, Italy
| | - Stefano Benini
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100 Bolzano, Italy
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9
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Caselli A, Paoli P, Santi A, Mugnaioni C, Toti A, Camici G, Cirri P. Low molecular weight protein tyrosine phosphatase: Multifaceted functions of an evolutionarily conserved enzyme. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:1339-55. [PMID: 27421795 DOI: 10.1016/j.bbapap.2016.07.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Revised: 07/05/2016] [Accepted: 07/11/2016] [Indexed: 12/31/2022]
Abstract
Originally identified as a low molecular weight acid phosphatase, LMW-PTP is actually a protein tyrosine phosphatase that acts on many phosphotyrosine-containing cellular proteins that are primarily involved in signal transduction. Differences in sequence, structure, and substrate recognition as well as in subcellular localization in different organisms enable LMW-PTP to exert many different functions. In fact, during evolution, the LMW-PTP structure adapted to perform different catalytic actions depending on the organism type. In bacteria, this enzyme is involved in the biosynthesis of group 1 and 4 capsules, but it is also a virulence factor in pathogenic strains. In yeast, LMW-PTPs dephosphorylate immunophilin Fpr3, a peptidyl-prolyl-cis-trans isomerase member of the protein chaperone family. In humans, LMW-PTP is encoded by the ACP1 gene, which is composed of three different alleles, each encoding two active enzymes produced by alternative RNA splicing. In animals, LMW-PTP dephosphorylates a number of growth factor receptors and modulates their signalling processes. The involvement of LMW-PTP in cancer progression and in insulin receptor regulation as well as its actions as a virulence factor in a number of pathogenic bacterial strains may promote the search for potent, selective and bioavailable LMW-PTP inhibitors.
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Affiliation(s)
- Anna Caselli
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Firenze, Viale Morgagni 50, 50134 Florence, Italy.
| | - Paolo Paoli
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Firenze, Viale Morgagni 50, 50134 Florence, Italy.
| | - Alice Santi
- Vascular Proteomics, Cancer Research UK Beatson Institute, Switchback Road, Glasgow G61 1BD, UK.
| | - Camilla Mugnaioni
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Firenze, Viale Morgagni 50, 50134 Florence, Italy.
| | - Alessandra Toti
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Firenze, Viale Morgagni 50, 50134 Florence, Italy.
| | - Guido Camici
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Firenze, Viale Morgagni 50, 50134 Florence, Italy.
| | - Paolo Cirri
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Firenze, Viale Morgagni 50, 50134 Florence, Italy.
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10
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Benini S, Caputi L, Cianci M. Cloning, purification, crystallization and 1.57 Å resolution X-ray data analysis of AmsI, the tyrosine phosphatase controlling amylovoran biosynthesis in the plant pathogen Erwinia amylovora. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2014; 70:1693-6. [PMID: 25484228 DOI: 10.1107/s2053230x14024947] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 11/13/2014] [Indexed: 02/02/2023]
Abstract
The Gram-negative bacterium Erwinia amylovora is a destructive pathogen of plants belonging to the Rosaceae family. Amongst its pathogenicity factors, E. amylovora produces the exopolysaccharide amylovoran, which contributes to the occlusion of plant vessels, causing wilting of shoots and eventually resulting in plant death. Amylovoran biosynthesis requires the presence of 12 genes (from amsA to amsL) clustered in the ams region of the E. amylovora genome. They mostly encode glycosyl transferases (AmsG, AmsB, AmsD, AmsE, AmsJ and AmsK), proteins involved in amylovoran translocation and assembly (AmsH, AmsL and AmsC), and also a tyrosine kinase (AmsA) and a tyrosine phosphatase (AmsI), which are both involved in the regulation of amylovoran biosynthesis. The low-molecular-weight protein tyrosine phosphatase AmsI was overexpressed as a His6-tagged protein in Escherichia coli, purified and crystallized. X-ray diffraction data were collected to a maximum resolution of 1.57 Å in space group P3121.
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Affiliation(s)
- Stefano Benini
- Laboratory of Bioorganic Chemistry and Bio-Crystallography (B2Cl), Faculty of Science and Technology, Free University of Bolzano, Piazza Università 5, 39100 Bolzano, Italy
| | - Lorenzo Caputi
- Biological Chemistry Department, John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, England
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11
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Temel DB, Dutta K, Alphonse S, Nourikyan J, Grangeasse C, Ghose R. Regulatory interactions between a bacterial tyrosine kinase and its cognate phosphatase. J Biol Chem 2013; 288:15212-28. [PMID: 23543749 DOI: 10.1074/jbc.m113.457804] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cyclic process of autophosphorylation of the C-terminal tyrosine cluster (YC) of a bacterial tyrosine kinase and its subsequent dephosphorylation following interactions with a counteracting tyrosine phosphatase regulates diverse physiological processes, including the biosynthesis and export of polysaccharides responsible for the formation of biofilms or virulence-determining capsules. We provide here the first detailed insight into this hitherto uncharacterized regulatory interaction at residue-specific resolution using Escherichia coli Wzc, a canonical bacterial tyrosine kinase, and its opposing tyrosine phosphatase, Wzb. The phosphatase Wzb utilizes a surface distal to the catalytic elements of the kinase, Wzc, to dock onto its catalytic domain (WzcCD). WzcCD binds in a largely YC-independent fashion near the Wzb catalytic site, inducing allosteric changes therein. YC dephosphorylation is proximity-mediated and reliant on the elevated concentration of phosphorylated YC near the Wzb active site resulting from WzcCD docking. Wzb principally recognizes the phosphate of its phosphotyrosine substrate and further stabilizes the tyrosine moiety through ring stacking interactions with a conserved active site tyrosine.
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Affiliation(s)
- Deniz B Temel
- Department of Chemistry, City College of New York, New York, New York 10031, USA
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12
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Protein Functional Dynamics in Multiple Timescales as Studied by NMR Spectroscopy. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2013; 92:219-51. [DOI: 10.1016/b978-0-12-411636-8.00006-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/10/2023]
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13
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Stehle T, Sreeramulu S, Löhr F, Richter C, Saxena K, Jonker HRA, Schwalbe H. The apo-structure of the low molecular weight protein-tyrosine phosphatase A (MptpA) from Mycobacterium tuberculosis allows for better target-specific drug development. J Biol Chem 2012; 287:34569-82. [PMID: 22888002 DOI: 10.1074/jbc.m112.399261] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Protein-tyrosine phosphatases (PTPs) and protein-tyrosine kinases co-regulate cellular processes. In pathogenic bacteria, they are frequently exploited to act as key virulence factors for human diseases. Mycobacterium tuberculosis, the causative organism of tuberculosis, secretes a low molecular weight PTP (LMW-PTP), MptpA, which is required for its survival upon infection of host macrophages. Although there is otherwise no sequence similarity of LMW-PTPs to other classes of PTPs, the phosphate binding loop (P-loop) CX(5)R and the loop containing a critical aspartic acid residue (D-loop), required for the catalytic activity, are well conserved. In most high molecular weight PTPs, ligand binding to the P-loop triggers a large conformational reorientation of the D-loop, in which it moves ∼10 Å, from an "open" to a "closed" conformation. Until now, there have been no ligand-free structures of LMW-PTPs described, and hence the dynamics of the D-loop have remained largely unknown for these PTPs. Here, we present a high resolution solution NMR structure of the free form of the MptpA LMW-PTP. In the absence of ligand and phosphate ions, the D-loop adopts an open conformation. Furthermore, we characterized the binding site of phosphate, a competitive inhibitor of LMW-PTPs, on MptpA and elucidated the involvement of both the P- and D-loop in phosphate binding. Notably, in LMW-PTPs, the phosphorylation status of two well conserved tyrosine residues, typically located in the D-loop, regulates the enzyme activity. PtkA, the kinase complementary to MptpA, phosphorylates these two tyrosine residues in MptpA. We characterized the MptpA-PtkA interaction by NMR spectroscopy to show that both the P- and D-loop form part of the binding interface.
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Affiliation(s)
- Tanja Stehle
- Institute for Organic Chemistry and Chemical Biology, ohann Wolfgang Goethe University, Max-von-Laue-Strasse 7, D-60438 Frankfurt am Main, Germany
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14
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Nadler C, Koby S, Peleg A, Johnson AC, Suddala KC, Sathiyamoorthy K, Smith BE, Saper MA, Rosenshine I. Cycling of Etk and Etp phosphorylation states is involved in formation of group 4 capsule by Escherichia coli. PLoS One 2012; 7:e37984. [PMID: 22675501 PMCID: PMC3366997 DOI: 10.1371/journal.pone.0037984] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Accepted: 04/27/2012] [Indexed: 11/30/2022] Open
Abstract
Capsules frequently play a key role in bacterial interactions with their environment. Escherichia coli capsules were categorized as groups 1 through 4, each produced by a distinct mechanism. Etk and Etp are members of protein families required for the production of group 1 and group 4 capsules. These members function as a protein tyrosine kinase and protein tyrosine phosphatase, respectively. We show that Etp dephosphorylates Etk in vivo, and mutations rendering Etk or Etp catalytically inactive result in loss of group 4 capsule production, supporting the notion that cyclic phosphorylation and dephosphorylation of Etk is required for capsule formation. Notably, Etp also becomes tyrosine phosphorylated in vivo and catalyzes rapid auto-dephosphorylation. Further analysis identified Tyr121 as the phosphorylated residue of Etp. Etp containing Phe, Glu or Ala in place of Tyr121 retained phosphatase activity and catalyzed dephosphorylation of Etp and Etk. Although EtpY121E and EtpY121A still supported capsule formation, EtpY121F failed to do so. These results suggest that cycles of phosphorylation and dephosphorylation of Etp, as well as Etk, are involved in the formation of group 4 capsule, providing an additional regulatory layer to the complex control of capsule production.
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Affiliation(s)
- Chen Nadler
- Department of Microbiology and Molecular Genetics, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Simi Koby
- Department of Microbiology and Molecular Genetics, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Adi Peleg
- Department of Microbiology and Molecular Genetics, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Austin C. Johnson
- Program in Biophysics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Krishna C. Suddala
- Program in Biophysics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Karthik Sathiyamoorthy
- Program in Biophysics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Bennett E. Smith
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Mark A. Saper
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail: (IR); (MAS)
| | - Ilan Rosenshine
- Department of Microbiology and Molecular Genetics, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
- * E-mail: (IR); (MAS)
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15
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Standish AJ, Salim AA, Zhang H, Capon RJ, Morona R. Chemical inhibition of bacterial protein tyrosine phosphatase suppresses capsule production. PLoS One 2012; 7:e36312. [PMID: 22629313 PMCID: PMC3356977 DOI: 10.1371/journal.pone.0036312] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Accepted: 04/01/2012] [Indexed: 12/12/2022] Open
Abstract
Capsule polysaccharide is a major virulence factor for a wide range of bacterial pathogens, including Streptococcus pneumoniae. The biosynthesis of Wzy-dependent capsules in both gram-negative and -positive bacteria is regulated by a system involving a protein tyrosine phosphatase (PTP) and a protein tyrosine kinase. However, how the system functions is still controversial. In Streptococcus pneumoniae, a major human pathogen, the system is present in all but 2 of the 93 serotypes found to date. In order to study this regulation further, we performed a screen to find inhibitors of the phosphatase, CpsB. This led to the observation that a recently discovered marine sponge metabolite, fascioquinol E, inhibited CpsB phosphatase activity both in vitro and in vivo at concentrations that did not affect the growth of the bacteria. This inhibition resulted in decreased capsule synthesis in D39 and Type 1 S. pneumoniae. Furthermore, concentrations of Fascioquinol E that inhibited capsule also lead to increased attachment of pneumococci to a macrophage cell line, suggesting that this compound would inhibit the virulence of the pathogen. Interestingly, this compound also inhibited the phosphatase activity of the structurally unrelated gram-negative PTP, Wzb, which belongs to separate family of protein tyrosine phosphatases. Furthermore, incubation with Klebsiella pneumoniae, which contains a homologous phosphatase, resulted in decreased capsule synthesis. Taken together, these data provide evidence that PTPs are critical for Wzy-dependent capsule production across a spectrum of bacteria, and as such represents a valuable new molecular target for the development of anti-virulence antibacterials.
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Affiliation(s)
- Alistair J Standish
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia.
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16
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Maccari R, Ottanà R. Low molecular weight phosphotyrosine protein phosphatases as emerging targets for the design of novel therapeutic agents. J Med Chem 2011; 55:2-22. [PMID: 21988196 DOI: 10.1021/jm200607g] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Rosanna Maccari
- Dipartimento Farmaco-Chimico, Faculty of Pharmacy, University of Messina, Polo Universitario dell'Annunziata, 98168 Messina, Italy.
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17
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Global transcriptome analysis of the E. coli O157 response to Agrimonia pilosa extract. Mol Cell Toxicol 2011. [DOI: 10.1007/s13273-011-0036-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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18
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Reckseidler-Zenteno SL, Viteri DF, Moore R, Wong E, Tuanyok A, Woods DE. Characterization of the type III capsular polysaccharide produced by Burkholderia pseudomallei. J Med Microbiol 2010; 59:1403-1414. [DOI: 10.1099/jmm.0.022202-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Burkholderia pseudomallei has been shown to produce more than one capsular polysaccharide (CPS). Analysis of the B. pseudomallei genome has revealed that the organism contains four CPS operons (I–IV). One of these operons (CPS III) was selected for further study. Comparative sequencing analysis revealed that the genes encoding CPS III are present in B. pseudomallei and Burkholderia thailandensis but not in Burkholderia mallei. In this study, CPS III was not found to contribute to the virulence of B. pseudomallei. Strains containing mutations in CPS III had the same LD50 value as the wild-type when tested in an animal infection model. Production of CPS III was shown to be induced in water but inhibited in 30 % normal human serum using a lux reporter fusion assay. Microarray analysis of capsule gene expression in infected hamsters revealed that the genes encoding CPS III were not significantly expressed in vivo compared with the genes encoding the previously characterized mannoheptose capsule (CPS I), which is an important virulence factor in B. pseudomallei. Glycosyl-composition analysis by combined GC/MS indicated that the CPS III genes are involved in the synthesis of a capsule composed of galactose, glucose, mannose and xylose.
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Affiliation(s)
- Shauna L. Reckseidler-Zenteno
- Centre for Science, Athabasca University, Athabasca, AB T9S 9Z9, Canada
- Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Center, Calgary, AB T2N 4N1, Canada
| | - Duber-Frey Viteri
- Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Center, Calgary, AB T2N 4N1, Canada
| | - Richard Moore
- Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Center, Calgary, AB T2N 4N1, Canada
| | - Erica Wong
- Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Center, Calgary, AB T2N 4N1, Canada
| | - Apichai Tuanyok
- Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Center, Calgary, AB T2N 4N1, Canada
| | - Donald E. Woods
- Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Center, Calgary, AB T2N 4N1, Canada
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Hu J, Li D, Su XD, Jin C, Xia B. Solution structure and conformational heterogeneity of acylphosphatase from Bacillus subtilis. FEBS Lett 2010; 584:2852-6. [PMID: 20447399 DOI: 10.1016/j.febslet.2010.04.069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 04/26/2010] [Accepted: 04/26/2010] [Indexed: 10/19/2022]
Abstract
Acylphosphatase is a small enzyme that catalyzes the hydrolysis of acyl phosphates. Here, we present the solution structure of acylphosphatase from Bacillus subtilis (BsAcP), the first from a Gram-positive bacterium. We found that its active site is disordered, whereas it converted to an ordered state upon ligand binding. The structure of BsAcP is sensitive to pH and it has multiple conformations in equilibrium at acidic pH (pH<5.8). Only one main conformation could bind ligand, and the relative population of these states is modulated by ligand concentration. This study provides direct evidence for the role of ligand in conformational selection.
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Affiliation(s)
- Jicheng Hu
- Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing, China
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20
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Blobel J, Bernadó P, Xu H, Jin C, Pons M. Weak oligomerization of low-molecular-weight protein tyrosine phosphatase is conserved from mammals to bacteria. FEBS J 2009; 276:4346-57. [PMID: 19678837 DOI: 10.1111/j.1742-4658.2009.07139.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The well-characterized self-association of a mammalian low-molecular-weight protein tyrosine phosphatase (lmwPTP) produces inactive oligomers that are in equilibrium with active monomers. A role of the inactive oligomers as supramolecular proenzymes has been suggested. The oligomerization equilibrium of YwlE, a lmwPTP from Bacillus subtilis, was studied by NMR. Chemical shift data and NMR relaxation confirm that dimerization takes place through the enzyme's active site, and is fully equivalent to the dimerization previously characterized in a eukaryotic low-molecular-weight phosphatase, with similarly large dissociation constants. The similarity between the oligomerization of prokaryotic and eukaryotic phosphatases extends beyond the dimer and involves higher order oligomers detected by NMR relaxation analysis at high protein concentrations. The conservation across different kingdoms of life suggests a physiological role for lmwPTP oligomerization in spite of the weak association observed in vitro. Structural data suggest that substrate modulation of the oligomerization equilibrium could be a regulatory mechanism leading to the generation of signaling pulses. The presence of a phenylalanine residue in the dimerization site of YwlE, replacing a tyrosine residue conserved in all eukaryotic lmwPTPs, demonstrates that lmwPTP regulation by oligomerization can be independent from tyrosine phosphorylation.
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Affiliation(s)
- Jascha Blobel
- Laboratory of Biomolecular NMR, Institute for Research in Biomedicine, Barcelona, Spain
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21
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Huang H, Hagelueken G, Whitfield C, Naismith JH. Crystallization and preliminary crystallographic analysis of the bacterial capsule assembly-regulating tyrosine phosphatases Wzb of Escherichia coli and Cps4B of Streptococcus pneumoniae. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:770-2. [PMID: 19652335 PMCID: PMC2720329 DOI: 10.1107/s1744309109023914] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Accepted: 06/22/2009] [Indexed: 11/18/2022]
Abstract
Bacterial tyrosine kinases and their cognate phosphatases are key players in the regulation of capsule assembly and thus are important virulence determinants of these bacteria. Examples of the kinase/phosphatase pairing are found in Gram-negative bacteria such as Escherichia coli (Wzc and Wzb) and in Gram-positive bacteria such as Streptococcus pneumoniae (CpsCD and CpsB). Although Wzb and Cps4B are both predicted to dephosphorylate the C-terminal tyrosine cluster of their cognate tyrosine kinase, they appear on the basis of protein sequence to belong to quite different enzyme classes. Recombinant purified proteins Cps4B of S. pneumoniae TIGR4 and Wzb of E. coli K-30 have been crystallized. Wzb crystals belonged to space-group family P3(x)21 and diffracted to 2.7 A resolution. Crystal form I of Cps4B belonged to space-group family P4(x)2(1)2 and diffracted to 2.8 A resolution; crystal form II belonged to space group P2(1)2(1)2(1) and diffracted to 1.9 A resolution.
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Affiliation(s)
- Hexian Huang
- Centre for Biomolecular Sciences, The University of St Andrews, Fife KY16 9RH, Scotland
| | - Gregor Hagelueken
- Centre for Biomolecular Sciences, The University of St Andrews, Fife KY16 9RH, Scotland
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Ontario N1G 2W1, Canada
| | - James H. Naismith
- Centre for Biomolecular Sciences, The University of St Andrews, Fife KY16 9RH, Scotland
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22
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Hagelueken G, Huang H, Mainprize IL, Whitfield C, Naismith JH. Crystal structures of Wzb of Escherichia coli and CpsB of Streptococcus pneumoniae, representatives of two families of tyrosine phosphatases that regulate capsule assembly. J Mol Biol 2009; 392:678-88. [PMID: 19616007 PMCID: PMC2777267 DOI: 10.1016/j.jmb.2009.07.026] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 07/07/2009] [Accepted: 07/09/2009] [Indexed: 12/11/2022]
Abstract
Many Gram-positive and Gram-negative bacteria utilize polysaccharide surface layers called capsules to evade the immune system; consequently, the synthesis and export of the capsule are a potential therapeutic target. In Escherichia coli K-30, the integral membrane tyrosine autokinase Wzc and the cognate phosphatase Wzb have been shown to be key for both synthesis and assembly of capsular polysaccharides. In the Gram-positive bacterium Streptococcus pneumoniae, the CpsCD complex is analogous to Wzc and the phosphatase CpsB is the corresponding cognate phosphatase. The phosphatases are known to dephosphorylate their corresponding autokinases, yet despite their functional equivalence, they share no sequence homology. We present the structure of Wzb in complex with phosphate and high-resolution structures of apo-CpsB and a phosphate-complexed CpsB. We show that both proteins are active toward Wzc and thereby demonstrate that CpsB is not specific for CpsCD. CpsB is a novel enzyme and represents the first solved structure of a tyrosine phosphatase from a Gram-positive bacterium. Wzb and CpsB have completely different structures, suggesting that they must operate by very different mechanisms. Although the mechanism of Wzb can be inferred from previous studies, CpsB appears to have a tyrosine phosphatase mechanism not observed before. We propose a chemical mechanism for CpsB based on site-directed mutagenesis and structural data.
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Affiliation(s)
- Gregor Hagelueken
- Centre for Biomolecular Sciences, The University of St. Andrews, Fife KY16 9RH, UK
| | - Hexian Huang
- Centre for Biomolecular Sciences, The University of St. Andrews, Fife KY16 9RH, UK
| | - Iain L. Mainprize
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - James H. Naismith
- Centre for Biomolecular Sciences, The University of St. Andrews, Fife KY16 9RH, UK
- Corresponding author.
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23
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Aoki SK, Malinverni JC, Jacoby K, Thomas B, Pamma R, Trinh BN, Remers S, Webb J, Braaten BA, Silhavy TJ, Low DA. Contact-dependent growth inhibition requires the essential outer membrane protein BamA (YaeT) as the receptor and the inner membrane transport protein AcrB. Mol Microbiol 2008; 70:323-40. [PMID: 18761695 DOI: 10.1111/j.1365-2958.2008.06404.x] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Contact-dependent growth inhibition (CDI) is a phenomenon by which bacterial cell growth is regulated by direct cell-to-cell contact via the CdiA/CdiB two-partner secretion system. Characterization of mutants resistant to CDI allowed us to identify BamA (YaeT) as the outer membrane receptor for CDI and AcrB as a potential downstream target. Notably, both BamA and AcrB are part of distinct multi-component machines. The Bam machine assembles outer membrane beta-barrel proteins into the outer membrane and the Acr machine exports small molecules into the extracellular milieu. We discovered that a mutation that reduces expression of BamA decreased binding of CDI+ inhibitor cells, measured by flow cytometry with fluorescently labelled bacteria. In addition, alpha-BamA antibodies, which recognized extracellular epitopes of BamA based on immunofluorescence, specifically blocked inhibitor-target cells binding and CDI. A second class of CDI-resistant mutants identified carried null mutations in the acrB gene. AcrB is an inner membrane component of a multidrug efflux pump that normally forms a cell envelope-spanning complex with the membrane fusion protein AcrA and the outer membrane protein TolC. Strikingly, the requirement for the BamA and AcrB proteins in CDI is independent of their multi-component machines, and thus their role in the CDI pathway may reflect novel, import-related functions.
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Affiliation(s)
- Stephanie K Aoki
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
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24
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Tabernero L, Aricescu AR, Jones EY, Szedlacsek SE. Protein tyrosine phosphatases: structure-function relationships. FEBS J 2008; 275:867-82. [PMID: 18298793 DOI: 10.1111/j.1742-4658.2008.06251.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Structural analysis of protein tyrosine phosphatases (PTPs) has expanded considerably in the last several years, producing more than 200 structures in this class of enzymes (from 35 different proteins and their complexes with ligands). The small-medium size of the catalytic domain of approximately 280 residues plus a very compact fold makes it amenable to cloning and overexpression in bacterial systems thus facilitating crystallographic analysis. The low molecular weight PTPs being even smaller, approximately 150 residues, are also perfect targets for NMR analysis. The availability of different structures and complexes of PTPs with substrates and inhibitors has provided a wealth of information with profound effects in the way we understand their biological functions. Developments in mammalian expression technology recently led to the first crystal structure of a receptor-like PTP extracellular region. Altogether, the PTP structural work significantly advanced our knowledge regarding the architecture, regulation and substrate specificity of these enzymes. In this review, we compile the most prominent structural traits that characterize PTPs and their complexes with ligands. We discuss how the data can be used to design further functional experiments and as a basis for drug design given that many PTPs are now considered strategic therapeutic targets for human diseases such as diabetes and cancer.
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