1
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Ross PA, Xu W, Jalomo-Khayrova E, Bange G, Gumerov VM, Bradley PH, Sourjik V, Zhulin IB. Framework for exploring the sensory repertoire of the human gut microbiota. mBio 2024; 15:e0103924. [PMID: 38757952 PMCID: PMC11237719 DOI: 10.1128/mbio.01039-24] [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: 04/09/2024] [Accepted: 04/17/2024] [Indexed: 05/18/2024] Open
Abstract
Bacteria sense changes in their environment and transduce signals to adjust their cellular functions accordingly. For this purpose, bacteria employ various sensors feeding into multiple signal transduction pathways. Signal recognition by bacterial sensors is studied mainly in a few model organisms, but advances in genome sequencing and analysis offer new ways of exploring the sensory repertoire of many understudied organisms. The human gut is a natural target of this line of study: it is a nutrient-rich and dynamic environment and is home to thousands of bacterial species whose activities impact human health. Many gut commensals are also poorly studied compared to model organisms and are mainly known through their genome sequences. To begin exploring the signals human gut commensals sense and respond to, we have designed a framework that enables the identification of sensory domains, prediction of signals that they recognize, and experimental verification of these predictions. We validate this framework's functionality by systematically identifying amino acid sensors in selected bacterial genomes and metagenomes, characterizing their amino acid binding properties, and demonstrating their signal transduction potential.IMPORTANCESignal transduction is a central process governing how bacteria sense and respond to their environment. The human gut is a complex environment with many living organisms and fluctuating streams of nutrients. One gut inhabitant, Escherichia coli, is a model organism for studying signal transduction. However, E. coli is not representative of most gut microbes, and signaling pathways in the thousands of other organisms comprising the human gut microbiota remain poorly understood. This work provides a foundation for how to explore signals recognized by these organisms.
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Affiliation(s)
- Patricia A. Ross
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio, USA
| | - Wenhao Xu
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Ekaterina Jalomo-Khayrova
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
- Department of Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Gert Bange
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
- Department of Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Vadim M. Gumerov
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio, USA
| | - Patrick H. Bradley
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Infectious Diseases Institute, The Ohio State University, Columbus, Ohio, USA
| | - Victor Sourjik
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Igor B. Zhulin
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio, USA
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2
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Zhou B, Garber JM, Vlach J, Azadi P, Ng KKS, Escalante-Semerena JC, Szymanski CM. Campylobacter jejuni uses energy taxis and a dehydrogenase enzyme for l-fucose chemotaxis. mBio 2023; 14:e0273223. [PMID: 38032212 PMCID: PMC10746189 DOI: 10.1128/mbio.02732-23] [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: 10/11/2023] [Accepted: 10/17/2023] [Indexed: 12/01/2023] Open
Abstract
IMPORTANCE In this study, we identify a separate role for the Campylobacter jejuni l-fucose dehydrogenase in l-fucose chemotaxis and demonstrate that this mechanism is not only limited to C. jejuni but is also present in Burkholderia multivorans. We now hypothesize that l-fucose energy taxis may contribute to the reduction of l-fucose-metabolizing strains of C. jejuni from the gastrointestinal tract of breastfed infants, selecting for isolates with increased colonization potential.
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Affiliation(s)
- Bibi Zhou
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Jolene M. Garber
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Jiri Vlach
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Kenneth K. S. Ng
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada
| | | | - Christine M. Szymanski
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
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3
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Engrola FSS, Paquete-Ferreira J, Santos-Silva T, Correia MAS, Leisico F, Santos MFA. Screening of Buffers and Additives for Protein Stabilization by Thermal Shift Assay: A Practical Approach. Methods Mol Biol 2023; 2652:199-213. [PMID: 37093477 DOI: 10.1007/978-1-0716-3147-8_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Thermal shift assay (TSA), also commonly designed by differential scanning fluorimetry (DSF) or ThermoFluor, is a technique relatively easy to implement and perform, useful in a myriad of applications. In addition to versatility, it is also rather inexpensive, making it suitable for high-throughput approaches. TSA uses a fluorescent dye to monitor the thermal denaturation of the protein under study and determine its melting temperature (Tm). One of its main applications is to identify the best buffers and additives that enhance protein stability.Understanding the TSA operating mode and the main methodological steps is a central key to designing effective experiments and retrieving meaningful conclusions. This chapter intends to present a straightforward TSA protocol, with different troubleshooting tips, to screen effective protein stabilizers such as buffers and additives, as well as data treatment and analysis. TSA results provide conditions in which the protein of interest is stable and therefore suitable to carry out further biophysical and structural characterization.
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Affiliation(s)
- Filipa S S Engrola
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- UCIBIO, Applied Molecular Biosciences Unit, Chemistry Department, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - João Paquete-Ferreira
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- UCIBIO, Applied Molecular Biosciences Unit, Chemistry Department, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Teresa Santos-Silva
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- UCIBIO, Applied Molecular Biosciences Unit, Chemistry Department, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Márcia A S Correia
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
- UCIBIO, Applied Molecular Biosciences Unit, Chemistry Department, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
| | - Francisco Leisico
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
- UCIBIO, Applied Molecular Biosciences Unit, Chemistry Department, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
- Institut de Biologie Structurale, UMR 5075, University Grenoble Alpes, CNRS, CEA, Grenoble, France.
| | - Marino F A Santos
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
- UCIBIO, Applied Molecular Biosciences Unit, Chemistry Department, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
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4
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Pinz S, Doskocil E, Seufert W. Thermofluor-Based Analysis of Protein Integrity and Ligand Interactions. Methods Mol Biol 2022; 2533:247-257. [PMID: 35796993 PMCID: PMC9761908 DOI: 10.1007/978-1-0716-2501-9_15] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Thermofluor is a fluorescence-based thermal shift assay, which measures temperature-induced protein unfolding and thereby yields valuable information about the integrity of a purified recombinant protein. Analysis of ligand binding to a protein is another popular application of this assay. Thermofluor requires neither protein labeling nor highly specialized equipment, and can be performed in a regular real-time PCR instrument. Thus, for a typical molecular biology laboratory, Thermofluor is a convenient method for the routine assessment of protein quality. Here, we provide Thermofluor protocols using the example of Cdc123. This ATP-grasp protein is an essential assembly chaperone of the eukaryotic translation initiation factor eIF2. We also report on a destabilized mutant protein version and on the ATP-mediated thermal stabilization of wild-type Cdc123 illustrating protein integrity assessment and ligand binding analysis as two major applications of the Thermofluor assay.
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Affiliation(s)
- Sophia Pinz
- Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany.
| | - Eva Doskocil
- Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany
| | - Wolfgang Seufert
- Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany.
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5
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The dCache Chemoreceptor TlpA of Helicobacter pylori Binds Multiple Attractant and Antagonistic Ligands via Distinct Sites. mBio 2021; 12:e0181921. [PMID: 34340539 PMCID: PMC8406319 DOI: 10.1128/mbio.01819-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The Helicobacter pylori chemoreceptor TlpA plays a role in dampening host inflammation during chronic stomach colonization. TlpA has a periplasmic dCache_1 domain, a structure that is capable of sensing many ligands; however, the only characterized TlpA signals are arginine, bicarbonate, and acid. To increase our understanding of TlpA’s sensing profile, we screened for diverse TlpA ligands using ligand binding arrays. TlpA bound seven ligands with affinities in the low- to middle-micromolar ranges. Three of these ligands, arginine, fumarate, and cysteine, were TlpA-dependent chemoattractants, while the others elicited no response. Molecular docking experiments, site-directed point mutants, and competition surface plasmon resonance binding assays suggested that TlpA binds ligands via both the membrane-distal and -proximal dCache_1 binding pockets. Surprisingly, one of the nonactive ligands, glucosamine, acted as a chemotaxis antagonist, preventing the chemotaxis response to chemoattractant ligands, and acted to block the binding of ligands irrespective of whether they bound the membrane-distal or -proximal dCache_1 subdomains. In total, these results suggest that TlpA senses multiple attractant ligands as well as antagonist ones, an emerging theme in chemotaxis systems.
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6
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Boyeldieu A, Ali Chaouche A, Méjean V, Jourlin-Castelli C. Combining two optimized and affordable methods to assign chemoreceptors to a specific signal. Anal Biochem 2021; 620:114139. [PMID: 33621526 DOI: 10.1016/j.ab.2021.114139] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/20/2021] [Accepted: 02/12/2021] [Indexed: 01/01/2023]
Abstract
Chemotaxis allows bacteria to detect specific compounds and move accordingly. This pathway involves signal detection by chemoreceptors (MCPs). Attributing a chemoreceptor to a ligand is difficult because there is a lot of redundancy in the MCPs that recognize a single ligand. We propose a methodology to define which chemoreceptors bind a given ligand. First, an MCP is overproduced to increase sensitivity to the ligand(s) it recognizes, thus promoting accumulation of cells around an agarose plug containing a low attractant concentration. Second, the ligand-binding domain (LBD) of the chemoreceptor is fused to maltose-binding protein (MBP), which facilitates purification and provides a control for a thermal shift assay (TSA). An increase in the melting temperature of the LBD in the presence of the ligand indicates that the chemoreceptor directly binds it. We showed that overexpression of two Shewanella oneidensis chemoreceptors (SO_0987 and SO_1056) promoted swimming toward an agarose plug containing a low concentration of chromate. The LBD of each of the two chemoreceptors was fused to MBP. A TSA revealed that only the LBD from SO_1056 had its melting temperature increased by chromate. In conclusion, we describe an efficient approach to define chemoreceptor-ligand pairs before undertaking more-sophisticated biochemical and structural studies.
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Affiliation(s)
- Anne Boyeldieu
- Aix Marseille Univ, CNRS, BIP UMR 7281, IMM, IM2B, Marseille, France
| | | | - Vincent Méjean
- Aix Marseille Univ, CNRS, BIP UMR 7281, IMM, IM2B, Marseille, France
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7
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Cooper KG, Chong A, Kari L, Jeffrey B, Starr T, Martens C, McClurg M, Posada VR, Laughlin RC, Whitfield-Cargile C, Garry Adams L, Bryan LK, Little SV, Krath M, Lawhon SD, Steele-Mortimer O. Regulatory protein HilD stimulates Salmonella Typhimurium invasiveness by promoting smooth swimming via the methyl-accepting chemotaxis protein McpC. Nat Commun 2021; 12:348. [PMID: 33441540 PMCID: PMC7806825 DOI: 10.1038/s41467-020-20558-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 11/27/2020] [Indexed: 12/31/2022] Open
Abstract
In the enteric pathogen Salmonella enterica serovar Typhimurium, invasion and motility are coordinated by the master regulator HilD, which induces expression of the type III secretion system 1 (T3SS1) and motility genes. Methyl-accepting chemotaxis proteins (MCPs) detect specific ligands and control the direction of the flagellar motor, promoting tumbling and changes in direction (if a repellent is detected) or smooth swimming (in the presence of an attractant). Here, we show that HilD induces smooth swimming by upregulating an uncharacterized MCP (McpC), and this is important for invasion of epithelial cells. Remarkably, in vitro assays show that McpC can suppress tumbling and increase smooth swimming in the absence of exogenous ligands. Expression of mcpC is repressed by the universal regulator H-NS, which can be displaced by HilD. Our results highlight the importance of smooth swimming for Salmonella Typhimurium invasiveness and indicate that McpC can act via a ligand-independent mechanism when incorporated into the chemotactic receptor array.
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Affiliation(s)
- Kendal G Cooper
- Laboratory of Bacteriology, Rocky Mountain Laboratory, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Audrey Chong
- Laboratory of Bacteriology, Rocky Mountain Laboratory, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Laszlo Kari
- Laboratory of Bacteriology, Rocky Mountain Laboratory, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Brendan Jeffrey
- NIAID Bioinformatics and Computational Biosciences Branch, Rocky Mountain Laboratory, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Tregei Starr
- Laboratory of Bacteriology, Rocky Mountain Laboratory, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
- GlaxoSmithKline, Hamilton, MT, 59840, USA
| | - Craig Martens
- NIAID RML Research Technologies Section, Genomics Unit, Rocky Mountain Laboratory, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Molly McClurg
- Department of Biological and Health Sciences, Texas A&M University-Kingsville, Kingsville, TX, 78363, USA
| | - Victoria R Posada
- Department of Biological and Health Sciences, Texas A&M University-Kingsville, Kingsville, TX, 78363, USA
| | - Richard C Laughlin
- Department of Biological and Health Sciences, Texas A&M University-Kingsville, Kingsville, TX, 78363, USA
| | - Canaan Whitfield-Cargile
- Department of Veterinary Large Animal Clinical Sciences, Texas A&M College of Veterinary Medicine and Biomedical Sciences, College Station, TX, 77843, USA
| | - L Garry Adams
- Department of Veterinary Pathobiology, Texas A&M College of Veterinary Medicine and Biomedical Sciences, College Station, TX, 77843, USA
| | - Laura K Bryan
- Department of Veterinary Pathobiology, Texas A&M College of Veterinary Medicine and Biomedical Sciences, College Station, TX, 77843, USA
| | - Sara V Little
- Department of Veterinary Pathobiology, Texas A&M College of Veterinary Medicine and Biomedical Sciences, College Station, TX, 77843, USA
| | - Mary Krath
- Department of Veterinary Pathobiology, Texas A&M College of Veterinary Medicine and Biomedical Sciences, College Station, TX, 77843, USA
| | - Sara D Lawhon
- Department of Veterinary Pathobiology, Texas A&M College of Veterinary Medicine and Biomedical Sciences, College Station, TX, 77843, USA
| | - Olivia Steele-Mortimer
- Laboratory of Bacteriology, Rocky Mountain Laboratory, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA.
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8
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Matilla MA, Martín-Mora D, Krell T. The use of isothermal titration calorimetry to unravel chemotactic signalling mechanisms. Environ Microbiol 2020; 22:3005-3019. [PMID: 32329116 DOI: 10.1111/1462-2920.15035] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 12/13/2022]
Abstract
Chemotaxis is based on the action of chemosensory pathways and is typically initiated by the recognition of chemoeffectors at chemoreceptor ligand-binding domains (LBD). Chemosensory signalling is highly complex; aspect that is not only reflected in the intricate interaction between many signalling proteins but also in the fact that bacteria frequently possess multiple chemosensory pathways and often a large number of chemoreceptors, which are mostly of unknown function. We review here the usefulness of isothermal titration calorimetry (ITC) to study this complexity. ITC is the gold standard for studying binding processes due to its precision and sensitivity, as well as its capability to determine simultaneously the association equilibrium constant, enthalpy change and stoichiometry of binding. There is now evidence that members of all major LBD families can be produced as individual recombinant proteins that maintain their ligand-binding properties. High-throughput screening of these proteins using thermal shift assays offer interesting initial information on chemoreceptor ligands, providing the basis for microcalorimetric analyses and microbiological experimentation. ITC has permitted the identification and characterization of many chemoreceptors with novel specificities. This ITC-based approach can also be used to identify signal molecules that stimulate members of other families of sensor proteins.
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Affiliation(s)
- Miguel A Matilla
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - David Martín-Mora
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
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9
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Bai N, Roder H, Dickson A, Karanicolas J. Isothermal Analysis of ThermoFluor Data can readily provide Quantitative Binding Affinities. Sci Rep 2019; 9:2650. [PMID: 30804351 PMCID: PMC6389909 DOI: 10.1038/s41598-018-37072-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 11/30/2018] [Indexed: 01/20/2023] Open
Abstract
Differential scanning fluorimetry (DSF), also known as ThermoFluor or Thermal Shift Assay, has become a commonly-used approach for detecting protein-ligand interactions, particularly in the context of fragment screening. Upon binding to a folded protein, most ligands stabilize the protein; thus, observing an increase in the temperature at which the protein unfolds as a function of ligand concentration can serve as evidence of a direct interaction. While experimental protocols for this assay are well-developed, it is not straightforward to extract binding constants from the resulting data. Because of this, DSF is often used to probe for an interaction, but not to quantify the corresponding binding constant (Kd). Here, we propose a new approach for analyzing DSF data. Using unfolding curves at varying ligand concentrations, our "isothermal" approach collects from these the fraction of protein that is folded at a single temperature (chosen to be temperature near the unfolding transition). This greatly simplifies the subsequent analysis, because it circumvents the complicating temperature dependence of the binding constant; the resulting constant-temperature system can then be described as a pair of coupled equilibria (protein folding/unfolding and ligand binding/unbinding). The temperature at which the binding constants are determined can also be tuned, by adding chemical denaturants that shift the protein unfolding temperature. We demonstrate the application of this isothermal analysis using experimental data for maltose binding protein binding to maltose, and for two carbonic anhydrase isoforms binding to each of four inhibitors. To facilitate adoption of this new approach, we provide a free and easy-to-use Python program that analyzes thermal unfolding data and implements the isothermal approach described herein ( https://sourceforge.net/projects/dsf-fitting ).
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Affiliation(s)
- Nan Bai
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, 66045, USA
| | - Heinrich Roder
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Alex Dickson
- Department of Biochemistry & Molecular Biology and Department of Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, MI, 48824, USA
| | - John Karanicolas
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA.
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10
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Martín-Mora D, Fernández M, Velando F, Ortega Á, Gavira JA, Matilla MA, Krell T. Functional Annotation of Bacterial Signal Transduction Systems: Progress and Challenges. Int J Mol Sci 2018; 19:ijms19123755. [PMID: 30486299 PMCID: PMC6321045 DOI: 10.3390/ijms19123755] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 11/22/2018] [Accepted: 11/22/2018] [Indexed: 01/15/2023] Open
Abstract
Bacteria possess a large number of signal transduction systems that sense and respond to different environmental cues. Most frequently these are transcriptional regulators, two-component systems and chemosensory pathways. A major bottleneck in the field of signal transduction is the lack of information on signal molecules that modulate the activity of the large majority of these systems. We review here the progress made in the functional annotation of sensor proteins using high-throughput ligand screening approaches of purified sensor proteins or individual ligand binding domains. In these assays, the alteration in protein thermal stability following ligand binding is monitored using Differential Scanning Fluorimetry. We illustrate on several examples how the identification of the sensor protein ligand has facilitated the elucidation of the molecular mechanism of the regulatory process. We will also discuss the use of virtual ligand screening approaches to identify sensor protein ligands. Both approaches have been successfully applied to functionally annotate a significant number of bacterial sensor proteins but can also be used to study proteins from other kingdoms. The major challenge consists in the study of sensor proteins that do not recognize signal molecules directly, but that are activated by signal molecule-loaded binding proteins.
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Affiliation(s)
- David Martín-Mora
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain.
| | - Matilde Fernández
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain.
| | - Félix Velando
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain.
| | - Álvaro Ortega
- Department of Biochemistry and Molecular Biology 'B' and Immunology, Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence "Campus Mare Nostrum", 30100 Murcia, Spain.
| | - José A Gavira
- Laboratorio de Estudios Cristalográficos, IACT, (CSIC-UGR), Avenida las Palmeras 4, 18100 Armilla, Spain.
| | - Miguel A Matilla
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain.
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain.
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11
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Copp JN, Akiva E, Babbitt PC, Tokuriki N. Revealing Unexplored Sequence-Function Space Using Sequence Similarity Networks. Biochemistry 2018; 57:4651-4662. [PMID: 30052428 DOI: 10.1021/acs.biochem.8b00473] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The rapidly expanding number of protein sequences found in public databases can improve our understanding of how protein functions evolve. However, our current knowledge of protein function likely represents a small fraction of the diverse repertoire that exists in nature. Integrative computational methods can facilitate the discovery of new protein functions and enzymatic reactions through the observation and investigation of the complex sequence-structure-function relationships within protein superfamilies. Here, we highlight the use of sequence similarity networks (SSNs) to identify previously unexplored sequence and function space. We exemplify this approach using the nitroreductase (NTR) superfamily. We demonstrate that SSN investigations can provide a rapid and effective means to classify groups of proteins, therefore exposing experimentally unexplored sequences that may exhibit novel functionality. Integration of such approaches with systematic experimental characterization will expand our understanding of the functional diversity of enzymes and their associated physiological roles.
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Affiliation(s)
- Janine N Copp
- Michael Smith Laboratories , University of British Columbia , 2185 East Mall , Vancouver , British Columbia V6T 1Z4 , Canada
| | - Eyal Akiva
- Department of Bioengineering and Therapeutic Sciences , University of California , San Francisco , California 94158 , United States.,Quantitative Biosciences Institute , University of California , San Francisco , California 94143 , United States
| | - Patricia C Babbitt
- Department of Bioengineering and Therapeutic Sciences , University of California , San Francisco , California 94158 , United States.,Quantitative Biosciences Institute , University of California , San Francisco , California 94143 , United States
| | - Nobuhiko Tokuriki
- Michael Smith Laboratories , University of British Columbia , 2185 East Mall , Vancouver , British Columbia V6T 1Z4 , Canada
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