1
|
Duran E, Schmidt A, Welty R, Jalihal AP, Pitchiaya S, Walter NG. Utilizing functional cell-free extracts to dissect ribonucleoprotein complex biology at single-molecule resolution. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1787. [PMID: 37042458 PMCID: PMC10524090 DOI: 10.1002/wrna.1787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 03/06/2023] [Accepted: 03/21/2023] [Indexed: 04/13/2023]
Abstract
Cellular machineries that drive and regulate gene expression often rely on the coordinated assembly and interaction of a multitude of proteins and RNA together called ribonucleoprotein complexes (RNPs). As such, it is challenging to fully reconstitute these cellular machines recombinantly and gain mechanistic understanding of how they operate and are regulated within the complex environment that is the cell. One strategy for overcoming this challenge is to perform single molecule fluorescence microscopy studies within crude or recombinantly supplemented cell extracts. This strategy enables elucidation of the interaction and kinetic behavior of specific fluorescently labeled biomolecules within RNPs under conditions that approximate native cellular environments. In this review, we describe single molecule fluorescence microcopy approaches that dissect RNP-driven processes within cellular extracts, highlighting general strategies used in these methods. We further survey biological advances in the areas of pre-mRNA splicing and transcription regulation that have been facilitated through this approach. Finally, we conclude with a summary of practical considerations for the implementation of the featured approaches to facilitate their broader future implementation in dissecting the mechanisms of RNP-driven cellular processes. This article is categorized under: RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
Collapse
Affiliation(s)
- Elizabeth Duran
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Andreas Schmidt
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Robb Welty
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Ameya P Jalihal
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Sethuramasundaram Pitchiaya
- Michigan Center for Translational Pathology, Department of Pathology, Department of Urology, Michigan Medicine, Ann Arbor, Michigan, USA
| | - Nils G Walter
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| |
Collapse
|
2
|
Chu J, Romero A, Taulbee J, Aran K. Development of Single Molecule Techniques for Sensing and Manipulation of CRISPR and Polymerase Enzymes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2300328. [PMID: 37226388 PMCID: PMC10524706 DOI: 10.1002/smll.202300328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/20/2023] [Indexed: 05/26/2023]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) and polymerases are powerful enzymes and their diverse applications in genomics, proteomics, and transcriptomics have revolutionized the biotechnology industry today. CRISPR has been widely adopted for genomic editing applications and Polymerases can efficiently amplify genomic transcripts via polymerase chain reaction (PCR). Further investigations into these enzymes can reveal specific details about their mechanisms that greatly expand their use. Single-molecule techniques are an effective way to probe enzymatic mechanisms because they may resolve intermediary conformations and states with greater detail than ensemble or bulk biosensing techniques. This review discusses various techniques for sensing and manipulation of single biomolecules that can help facilitate and expedite these discoveries. Each platform is categorized as optical, mechanical, or electronic. The methods, operating principles, outputs, and utility of each technique are briefly introduced, followed by a discussion of their applications to monitor and control CRISPR and Polymerases at the single molecule level, and closing with a brief overview of their limitations and future prospects.
Collapse
Affiliation(s)
- Josephine Chu
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, CA, 91711, USA
| | - Andres Romero
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, CA, 91711, USA
| | - Jeffrey Taulbee
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, CA, 91711, USA
| | - Kiana Aran
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, CA, 91711, USA
- Cardea, San Diego, CA, 92121, USA
- University of California Berkeley, Berkeley, CA, 94720, USA
| |
Collapse
|
3
|
Agam G, Gebhardt C, Popara M, Mächtel R, Folz J, Ambrose B, Chamachi N, Chung SY, Craggs TD, de Boer M, Grohmann D, Ha T, Hartmann A, Hendrix J, Hirschfeld V, Hübner CG, Hugel T, Kammerer D, Kang HS, Kapanidis AN, Krainer G, Kramm K, Lemke EA, Lerner E, Margeat E, Martens K, Michaelis J, Mitra J, Moya Muñoz GG, Quast RB, Robb NC, Sattler M, Schlierf M, Schneider J, Schröder T, Sefer A, Tan PS, Thurn J, Tinnefeld P, van Noort J, Weiss S, Wendler N, Zijlstra N, Barth A, Seidel CAM, Lamb DC, Cordes T. Reliability and accuracy of single-molecule FRET studies for characterization of structural dynamics and distances in proteins. Nat Methods 2023; 20:523-535. [PMID: 36973549 PMCID: PMC10089922 DOI: 10.1038/s41592-023-01807-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 01/31/2023] [Indexed: 03/29/2023]
Abstract
Single-molecule Förster-resonance energy transfer (smFRET) experiments allow the study of biomolecular structure and dynamics in vitro and in vivo. We performed an international blind study involving 19 laboratories to assess the uncertainty of FRET experiments for proteins with respect to the measured FRET efficiency histograms, determination of distances, and the detection and quantification of structural dynamics. Using two protein systems with distinct conformational changes and dynamics, we obtained an uncertainty of the FRET efficiency ≤0.06, corresponding to an interdye distance precision of ≤2 Å and accuracy of ≤5 Å. We further discuss the limits for detecting fluctuations in this distance range and how to identify dye perturbations. Our work demonstrates the ability of smFRET experiments to simultaneously measure distances and avoid the averaging of conformational dynamics for realistic protein systems, highlighting its importance in the expanding toolbox of integrative structural biology.
Collapse
Affiliation(s)
- Ganesh Agam
- Department of Chemistry, Ludwig-Maximilians University München, München, Germany
| | - Christian Gebhardt
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians University München, Planegg-Martinsried, Germany
| | - Milana Popara
- Molecular Physical Chemistry, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Rebecca Mächtel
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians University München, Planegg-Martinsried, Germany
| | - Julian Folz
- Molecular Physical Chemistry, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | | | - Neharika Chamachi
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Dresden, Germany
| | - Sang Yoon Chung
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | | | - Marijn de Boer
- Molecular Microscopy Research Group, Zernike Institute for Advanced Materials, University of Groningen, AG Groningen, the Netherlands
| | - Dina Grohmann
- Department of Biochemistry, Genetics and Microbiology, Institute of Microbiology, Single-Molecule Biochemistry Laboratory, University of Regensburg, Regensburg, Germany
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine and Howard Hughes Medical Institute, Baltimore, MD, USA
| | - Andreas Hartmann
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Dresden, Germany
| | - Jelle Hendrix
- Dynamic Bioimaging Laboratory, Advanced Optical Microscopy Center and Biomedical Research Institute, Hasselt University, Agoralaan C (BIOMED), Hasselt, Belgium
- Department of Chemistry, KU Leuven, Leuven, Belgium
| | | | | | - Thorsten Hugel
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
- Signalling Research Centers BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Dominik Kammerer
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK
- Kavli Institute of Nanoscience Discovery, University of Oxford, Oxford, UK
| | - Hyun-Seo Kang
- Bayerisches NMR Zentrum, Department of Bioscience, School of Natural Sciences, Technical University of München, Garching, Germany
| | - Achillefs N Kapanidis
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK
- Kavli Institute of Nanoscience Discovery, University of Oxford, Oxford, UK
| | - Georg Krainer
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Dresden, Germany
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Kevin Kramm
- Department of Biochemistry, Genetics and Microbiology, Institute of Microbiology, Single-Molecule Biochemistry Laboratory, University of Regensburg, Regensburg, Germany
| | - Edward A Lemke
- Biocenter, Johannes Gutenberg University Mainz, Mainz, Germany
- Institute of Molecular Biology, Mainz, Germany
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Eitan Lerner
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, and The Center for Nanoscience and Nanotechnology, Faculty of Mathematics and Science, The Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Emmanuel Margeat
- Centre de Biologie Structurale (CBS), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Kirsten Martens
- Biological and Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, the Netherlands
| | | | - Jaba Mitra
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine and Howard Hughes Medical Institute, Baltimore, MD, USA
- Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Gabriel G Moya Muñoz
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians University München, Planegg-Martinsried, Germany
| | - Robert B Quast
- Centre de Biologie Structurale (CBS), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Nicole C Robb
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK
- Kavli Institute of Nanoscience Discovery, University of Oxford, Oxford, UK
- Warwick Medical School, The University of Warwick, Coventry, UK
| | - Michael Sattler
- Bayerisches NMR Zentrum, Department of Bioscience, School of Natural Sciences, Technical University of München, Garching, Germany
- Institute of Structural Biology, Molecular Targets and Therapeutics Center, Helmholtz Center Munich, Munich, Germany
| | - Michael Schlierf
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Dresden, Germany
- Cluster of Excellence Physics of Life, Technische Universität Dresden, Dresden, Germany
| | - Jonathan Schneider
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians University München, Planegg-Martinsried, Germany
| | - Tim Schröder
- Department of Chemistry, Ludwig-Maximilians University München, München, Germany
| | - Anna Sefer
- Institute for Biophysics, Ulm University, Ulm, Germany
| | - Piau Siong Tan
- Biocenter, Johannes Gutenberg University Mainz, Mainz, Germany
- Institute of Molecular Biology, Mainz, Germany
| | - Johann Thurn
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
- Institute of Technical Physics, German Aerospace Center (DLR), Stuttgart, Germany
| | - Philip Tinnefeld
- Department of Chemistry, Ludwig-Maximilians University München, München, Germany
| | - John van Noort
- Biological and Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, the Netherlands
| | - Shimon Weiss
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Nicolas Wendler
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians University München, Planegg-Martinsried, Germany
| | - Niels Zijlstra
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians University München, Planegg-Martinsried, Germany
| | - Anders Barth
- Molecular Physical Chemistry, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany.
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands.
| | - Claus A M Seidel
- Molecular Physical Chemistry, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany.
| | - Don C Lamb
- Department of Chemistry, Ludwig-Maximilians University München, München, Germany.
| | - Thorben Cordes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians University München, Planegg-Martinsried, Germany.
| |
Collapse
|
4
|
Theillet FX, Luchinat E. In-cell NMR: Why and how? PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 132-133:1-112. [PMID: 36496255 DOI: 10.1016/j.pnmrs.2022.04.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 04/19/2022] [Accepted: 04/27/2022] [Indexed: 06/17/2023]
Abstract
NMR spectroscopy has been applied to cells and tissues analysis since its beginnings, as early as 1950. We have attempted to gather here in a didactic fashion the broad diversity of data and ideas that emerged from NMR investigations on living cells. Covering a large proportion of the periodic table, NMR spectroscopy permits scrutiny of a great variety of atomic nuclei in all living organisms non-invasively. It has thus provided quantitative information on cellular atoms and their chemical environment, dynamics, or interactions. We will show that NMR studies have generated valuable knowledge on a vast array of cellular molecules and events, from water, salts, metabolites, cell walls, proteins, nucleic acids, drugs and drug targets, to pH, redox equilibria and chemical reactions. The characterization of such a multitude of objects at the atomic scale has thus shaped our mental representation of cellular life at multiple levels, together with major techniques like mass-spectrometry or microscopies. NMR studies on cells has accompanied the developments of MRI and metabolomics, and various subfields have flourished, coined with appealing names: fluxomics, foodomics, MRI and MRS (i.e. imaging and localized spectroscopy of living tissues, respectively), whole-cell NMR, on-cell ligand-based NMR, systems NMR, cellular structural biology, in-cell NMR… All these have not grown separately, but rather by reinforcing each other like a braided trunk. Hence, we try here to provide an analytical account of a large ensemble of intricately linked approaches, whose integration has been and will be key to their success. We present extensive overviews, firstly on the various types of information provided by NMR in a cellular environment (the "why", oriented towards a broad readership), and secondly on the employed NMR techniques and setups (the "how", where we discuss the past, current and future methods). Each subsection is constructed as a historical anthology, showing how the intrinsic properties of NMR spectroscopy and its developments structured the accessible knowledge on cellular phenomena. Using this systematic approach, we sought i) to make this review accessible to the broadest audience and ii) to highlight some early techniques that may find renewed interest. Finally, we present a brief discussion on what may be potential and desirable developments in the context of integrative studies in biology.
Collapse
Affiliation(s)
- Francois-Xavier Theillet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
| | - Enrico Luchinat
- Dipartimento di Scienze e Tecnologie Agro-Alimentari, Alma Mater Studiorum - Università di Bologna, Piazza Goidanich 60, 47521 Cesena, Italy; CERM - Magnetic Resonance Center, and Neurofarba Department, Università degli Studi di Firenze, 50019 Sesto Fiorentino, Italy
| |
Collapse
|
5
|
Zhang L, Isselstein M, Köhler J, Eleftheriadis N, Huisjes NM, Guirao-Ortiz M, Narducci A, Smit JH, Stoffels J, Harz H, Leonhardt H, Herrmann A, Cordes T. Linker Molecules Convert Commercial Fluorophores into Tailored Functional Probes during Biolabelling. Angew Chem Int Ed Engl 2022; 61:e202112959. [PMID: 35146855 PMCID: PMC9305292 DOI: 10.1002/anie.202112959] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Indexed: 12/27/2022]
Abstract
Many life‐science techniques and assays rely on selective labeling of biological target structures with commercial fluorophores that have specific yet invariant properties. Consequently, a fluorophore (or dye) is only useful for a limited range of applications, e.g., as a label for cellular compartments, super‐resolution imaging, DNA sequencing or for a specific biomedical assay. Modifications of fluorophores with the goal to alter their bioconjugation chemistry, photophysical or functional properties typically require complex synthesis schemes. We here introduce a general strategy that allows to customize these properties during biolabelling with the goal to introduce the fluorophore in the last step of biolabelling. For this, we present the design and synthesis of ‘linker’ compounds, that bridge biotarget, fluorophore and a functional moiety via well‐established labeling protocols. Linker molecules were synthesized via the Ugi four‐component reaction (Ugi‐4CR) which facilitates a modular design of linkers with diverse functional properties and bioconjugation‐ and fluorophore attachment moieties. To demonstrate the possibilities of different linkers experimentally, we characterized the ability of commercial fluorophores from the classes of cyanines, rhodamines, carbopyronines and silicon‐rhodamines to become functional labels on different biological targets in vitro and in vivo via thiol‐maleimide chemistry. With our strategy, we showed that the same commercial dye can become a photostable self‐healing dye or a sensor for bivalent ions subject to the linker used. Finally, we quantified the photophysical performance of different self‐healing linker–fluorophore conjugates and demonstrated their applications in super‐resolution imaging and single‐molecule spectroscopy.
Collapse
Affiliation(s)
- Lei Zhang
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany.,Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Michael Isselstein
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | - Jens Köhler
- (DWI) Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52056, Aachen, Germany.,& Institute of Technical and Macromolecular Chemistry, (RWTH) Aachen University, Worringerweg 2, 52074, Aachen, Germany
| | - Nikolaos Eleftheriadis
- Molecular Microscopy Research Group, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Nadia M Huisjes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany.,Molecular Microscopy Research Group, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Miguel Guirao-Ortiz
- Human Biology & Bioimaging, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | - Alessandra Narducci
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | - Jochem H Smit
- Molecular Microscopy Research Group, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Janko Stoffels
- (DWI) Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52056, Aachen, Germany.,& Institute of Technical and Macromolecular Chemistry, (RWTH) Aachen University, Worringerweg 2, 52074, Aachen, Germany
| | - Hartmann Harz
- Human Biology & Bioimaging, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | - Heinrich Leonhardt
- Human Biology & Bioimaging, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | - Andreas Herrmann
- (DWI) Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52056, Aachen, Germany.,& Institute of Technical and Macromolecular Chemistry, (RWTH) Aachen University, Worringerweg 2, 52074, Aachen, Germany
| | - Thorben Cordes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany.,Molecular Microscopy Research Group, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| |
Collapse
|
6
|
Abstract
In-cell structural biology aims at extracting structural information about proteins or nucleic acids in their native, cellular environment. This emerging field holds great promise and is already providing new facts and outlooks of interest at both fundamental and applied levels. NMR spectroscopy has important contributions on this stage: It brings information on a broad variety of nuclei at the atomic scale, which ensures its great versatility and uniqueness. Here, we detail the methods, the fundamental knowledge, and the applications in biomedical engineering related to in-cell structural biology by NMR. We finally propose a brief overview of the main other techniques in the field (EPR, smFRET, cryo-ET, etc.) to draw some advisable developments for in-cell NMR. In the era of large-scale screenings and deep learning, both accurate and qualitative experimental evidence are as essential as ever to understand the interior life of cells. In-cell structural biology by NMR spectroscopy can generate such a knowledge, and it does so at the atomic scale. This review is meant to deliver comprehensive but accessible information, with advanced technical details and reflections on the methods, the nature of the results, and the future of the field.
Collapse
Affiliation(s)
- Francois-Xavier Theillet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| |
Collapse
|
7
|
Dam T, Chouliara M, Junghans V, Jönsson P. Supported Lipid Bilayers and the Study of Two-Dimensional Binding Kinetics. Front Mol Biosci 2022; 9:833123. [PMID: 35252352 PMCID: PMC8896763 DOI: 10.3389/fmolb.2022.833123] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 01/27/2022] [Indexed: 11/13/2022] Open
Abstract
Binding between protein molecules on contacting cells is essential in initiating and regulating several key biological processes. In contrast to interactions between molecules in solution, these events are restricted to the two-dimensional (2D) plane of the meeting cell surfaces. However, converting between the more commonly available binding kinetics measured in solution and the so-called 2D binding kinetics has proven a complicated task since for the latter several factors other than the protein-protein interaction per se have an impact. A few important examples of these are: protein density, membrane fluctuations, force on the bond and the use of auxiliary binding molecules. The development of model membranes, and in particular supported lipid bilayers (SLBs), has made it possible to simplify the studied contact to analyze these effects and to measure 2D binding kinetics of individual protein-protein interactions. We will in this review give an overview of, and discuss, how different SLB systems have been used for this and compare different methods to measure binding kinetics in cell-SLB contacts. Typically, the SLB is functionalized with fluorescently labelled ligands whose interaction with the corresponding receptor on a binding cell can be detected. This interaction can either be studied 1) by an accumulation of ligands in the cell-SLB contact, whose magnitude depends on the density of the proteins and binding affinity of the interaction, or 2) by tracking single ligands in the SLB, which upon interaction with a receptor result in a change of motion of the diffusing ligand. The advantages and disadvantages of other methods measuring 2D binding kinetics will also be discussed and compared to the fluorescence-based methods. Although binding kinetic measurements in cell-SLB contacts have provided novel information on how ligands interact with receptors in vivo the number of these measurements is still limited. This is influenced by the complexity of the system as well as the required experimental time. Moreover, the outcome can vary significantly between studies, highlighting the necessity for continued development of methods to study 2D binding kinetics with higher precision and ease.
Collapse
Affiliation(s)
- Tommy Dam
- Department of Chemistry, Lund University, Lund, Sweden
| | | | - Victoria Junghans
- Nuffield Department of Medicine, CAMS Oxford Institute, University of Oxford, Oxford, United Kingdom
| | - Peter Jönsson
- Department of Chemistry, Lund University, Lund, Sweden
- *Correspondence: Peter Jönsson,
| |
Collapse
|
8
|
Zhang L, Isselstein M, Köhler J, Eleftheriadis N, Huisjes N, Guirao M, Narducci A, Smit J, Stoffels J, Harz H, Leonhardt H, Herrmann A, Cordes T. Linker Molecules Convert Commercial Fluorophores into Tailored Functional Probes during Bio‐labeling. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202112959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Lei Zhang
- LMU München: Ludwig-Maximilians-Universitat Munchen Biocenter GERMANY
| | | | - Jens Köhler
- DWI-Leibniz-Institut für Interaktive Materialien: DWI-Leibniz-Institut fur Interaktive Materialien Chemie GERMANY
| | | | - Nadia Huisjes
- RUG: Rijksuniversiteit Groningen Zernike NETHERLANDS
| | - Miguel Guirao
- LMU München: Ludwig-Maximilians-Universitat Munchen Biocenter GERMANY
| | | | - Jochem Smit
- RUG: Rijksuniversiteit Groningen Zernike NETHERLANDS
| | - Janko Stoffels
- DWI-Leibniz-Institut für Interaktive Materialien: DWI-Leibniz-Institut fur Interaktive Materialien Chemistry GERMANY
| | - Hartmann Harz
- LMU München: Ludwig-Maximilians-Universitat Munchen Biocenter GERMANY
| | | | - Andreas Herrmann
- DWI-Leibniz-Institut für Interaktive Materialien: DWI-Leibniz-Institut fur Interaktive Materialien Chemistry GERMANY
| | - Thorben Cordes
- Ludwig-Maximilians-Universitat Munchen Faculty of Biology Großhadernerstr. 2-4 82152 Planegg-Martiensried GERMANY
| |
Collapse
|
9
|
Steffen FD, Sigel RKO, Börner R. FRETraj: Integrating single-molecule spectroscopy with molecular dynamics. Bioinformatics 2021; 37:3953-3955. [PMID: 34478493 DOI: 10.1093/bioinformatics/btab615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 07/17/2021] [Accepted: 09/01/2021] [Indexed: 11/14/2022] Open
Abstract
SUMMARY Quantitative interpretation of single-molecule FRET experiments requires a model of the dye dynamics to link experimental energy transfer efficiencies to distances between atom positions. We have developed FRETraj, a Python module to predict FRET distributions based on accessible-contact volumes (ACV) and simulated photon statistics. FRETraj helps to identify optimal fluorophore positions on a biomolecule of interest by rapidly evaluating donor-acceptor distances. FRETraj is scalable and fully integrated into PyMOL and the Jupyter ecosystem. Here we describe the conformational dynamics of a DNA hairpin by computing multiple ACVs along a molecular dynamics trajectory and compare the predicted FRET distribution with single-molecule experiments. FRET-assisted modeling will accelerate the analysis of structural ensembles in particular dynamic, non-coding RNAs and transient protein-nucleic acid complexes. AVAILABILITY FRETraj is implemented as a cross-platform Python package available under the GPL-3.0 on Github (https://github.com/RNA-FRETools/fretraj) and is documented at https://RNA-FRETools.github.io/fretraj. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
Collapse
Affiliation(s)
| | | | - Richard Börner
- Department of Chemistry, University of Zurich, Switzerland
| |
Collapse
|
10
|
Bartels K, Lasitza‐Male T, Hofmann H, Löw C. Single-Molecule FRET of Membrane Transport Proteins. Chembiochem 2021; 22:2657-2671. [PMID: 33945656 PMCID: PMC8453700 DOI: 10.1002/cbic.202100106] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/03/2021] [Indexed: 12/31/2022]
Abstract
Uncovering the structure and function of biomolecules is a fundamental goal in structural biology. Membrane-embedded transport proteins are ubiquitous in all kingdoms of life. Despite structural flexibility, their mechanisms are typically studied by ensemble biochemical methods or by static high-resolution structures, which complicate a detailed understanding of their dynamics. Here, we review the recent progress of single molecule Förster Resonance Energy Transfer (smFRET) in determining mechanisms and timescales of substrate transport across membranes. These studies do not only demonstrate the versatility and suitability of state-of-the-art smFRET tools for studying membrane transport proteins but they also highlight the importance of membrane mimicking environments in preserving the function of these proteins. The current achievements advance our understanding of transport mechanisms and have the potential to facilitate future progress in drug design.
Collapse
Affiliation(s)
- Kim Bartels
- Centre for Structural Systems Biology (CSSB)DESY and European Molecular Biology Laboratory HamburgNotkestrasse 8522607HamburgGermany
| | - Tanya Lasitza‐Male
- Department of Structural BiologyWeizmann Institute of ScienceHerzl St. 2347610001RehovotIsrael
| | - Hagen Hofmann
- Department of Structural BiologyWeizmann Institute of ScienceHerzl St. 2347610001RehovotIsrael
| | - Christian Löw
- Centre for Structural Systems Biology (CSSB)DESY and European Molecular Biology Laboratory HamburgNotkestrasse 8522607HamburgGermany
| |
Collapse
|
11
|
Lerner E, Barth A, Hendrix J, Ambrose B, Birkedal V, Blanchard SC, Börner R, Sung Chung H, Cordes T, Craggs TD, Deniz AA, Diao J, Fei J, Gonzalez RL, Gopich IV, Ha T, Hanke CA, Haran G, Hatzakis NS, Hohng S, Hong SC, Hugel T, Ingargiola A, Joo C, Kapanidis AN, Kim HD, Laurence T, Lee NK, Lee TH, Lemke EA, Margeat E, Michaelis J, Michalet X, Myong S, Nettels D, Peulen TO, Ploetz E, Razvag Y, Robb NC, Schuler B, Soleimaninejad H, Tang C, Vafabakhsh R, Lamb DC, Seidel CAM, Weiss S. FRET-based dynamic structural biology: Challenges, perspectives and an appeal for open-science practices. eLife 2021; 10:e60416. [PMID: 33779550 PMCID: PMC8007216 DOI: 10.7554/elife.60416] [Citation(s) in RCA: 125] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 02/09/2021] [Indexed: 12/18/2022] Open
Abstract
Single-molecule FRET (smFRET) has become a mainstream technique for studying biomolecular structural dynamics. The rapid and wide adoption of smFRET experiments by an ever-increasing number of groups has generated significant progress in sample preparation, measurement procedures, data analysis, algorithms and documentation. Several labs that employ smFRET approaches have joined forces to inform the smFRET community about streamlining how to perform experiments and analyze results for obtaining quantitative information on biomolecular structure and dynamics. The recent efforts include blind tests to assess the accuracy and the precision of smFRET experiments among different labs using various procedures. These multi-lab studies have led to the development of smFRET procedures and documentation, which are important when submitting entries into the archiving system for integrative structure models, PDB-Dev. This position paper describes the current 'state of the art' from different perspectives, points to unresolved methodological issues for quantitative structural studies, provides a set of 'soft recommendations' about which an emerging consensus exists, and lists openly available resources for newcomers and seasoned practitioners. To make further progress, we strongly encourage 'open science' practices.
Collapse
Affiliation(s)
- Eitan Lerner
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, and The Center for Nanoscience and Nanotechnology, Faculty of Mathematics & Science, The Edmond J. Safra Campus, The Hebrew University of JerusalemJerusalemIsrael
| | - Anders Barth
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-UniversitätDüsseldorfGermany
| | - Jelle Hendrix
- Dynamic Bioimaging Lab, Advanced Optical Microscopy Centre and Biomedical Research Institute (BIOMED), Hasselt UniversityDiepenbeekBelgium
| | - Benjamin Ambrose
- Department of Chemistry, University of SheffieldSheffieldUnited Kingdom
| | - Victoria Birkedal
- Department of Chemistry and iNANO center, Aarhus UniversityAarhusDenmark
| | - Scott C Blanchard
- Department of Structural Biology, St. Jude Children's Research HospitalMemphisUnited States
| | - Richard Börner
- Laserinstitut HS Mittweida, University of Applied Science MittweidaMittweidaGermany
| | - Hoi Sung Chung
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaUnited States
| | - Thorben Cordes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität MünchenPlanegg-MartinsriedGermany
| | - Timothy D Craggs
- Department of Chemistry, University of SheffieldSheffieldUnited Kingdom
| | - Ashok A Deniz
- Department of Integrative Structural and Computational Biology, The Scripps Research InstituteLa JollaUnited States
| | - Jiajie Diao
- Department of Cancer Biology, University of Cincinnati School of MedicineCincinnatiUnited States
| | - Jingyi Fei
- Department of Biochemistry and Molecular Biology and The Institute for Biophysical Dynamics, University of ChicagoChicagoUnited States
| | - Ruben L Gonzalez
- Department of Chemistry, Columbia UniversityNew YorkUnited States
| | - Irina V Gopich
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaUnited States
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Howard Hughes Medical InstituteBaltimoreUnited States
| | - Christian A Hanke
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-UniversitätDüsseldorfGermany
| | - Gilad Haran
- Department of Chemical and Biological Physics, Weizmann Institute of ScienceRehovotIsrael
| | - Nikos S Hatzakis
- Department of Chemistry & Nanoscience Centre, University of CopenhagenCopenhagenDenmark
- Denmark Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of CopenhagenCopenhagenDenmark
| | - Sungchul Hohng
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National UniversitySeoulRepublic of Korea
| | - Seok-Cheol Hong
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science and Department of Physics, Korea UniversitySeoulRepublic of Korea
| | - Thorsten Hugel
- Institute of Physical Chemistry and Signalling Research Centres BIOSS and CIBSS, University of FreiburgFreiburgGermany
| | - Antonino Ingargiola
- Department of Chemistry and Biochemistry, and Department of Physiology, University of California, Los AngelesLos AngelesUnited States
| | - Chirlmin Joo
- Department of BioNanoScience, Kavli Institute of Nanoscience, Delft University of TechnologyDelftNetherlands
| | - Achillefs N Kapanidis
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of OxfordOxfordUnited Kingdom
| | - Harold D Kim
- School of Physics, Georgia Institute of TechnologyAtlantaUnited States
| | - Ted Laurence
- Physical and Life Sciences Directorate, Lawrence Livermore National LaboratoryLivermoreUnited States
| | - Nam Ki Lee
- School of Chemistry, Seoul National UniversitySeoulRepublic of Korea
| | - Tae-Hee Lee
- Department of Chemistry, Pennsylvania State UniversityUniversity ParkUnited States
| | - Edward A Lemke
- Departments of Biology and Chemistry, Johannes Gutenberg UniversityMainzGermany
- Institute of Molecular Biology (IMB)MainzGermany
| | - Emmanuel Margeat
- Centre de Biologie Structurale (CBS), CNRS, INSERM, Universitié de MontpellierMontpellierFrance
| | | | - Xavier Michalet
- Department of Chemistry and Biochemistry, and Department of Physiology, University of California, Los AngelesLos AngelesUnited States
| | - Sua Myong
- Department of Biophysics, Johns Hopkins UniversityBaltimoreUnited States
| | - Daniel Nettels
- Department of Biochemistry and Department of Physics, University of ZurichZurichSwitzerland
| | - Thomas-Otavio Peulen
- Department of Bioengineering and Therapeutic Sciences, University of California, San FranciscoSan FranciscoUnited States
| | - Evelyn Ploetz
- Physical Chemistry, Department of Chemistry, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-UniversitätMünchenGermany
| | - Yair Razvag
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, and The Center for Nanoscience and Nanotechnology, Faculty of Mathematics & Science, The Edmond J. Safra Campus, The Hebrew University of JerusalemJerusalemIsrael
| | - Nicole C Robb
- Warwick Medical School, University of WarwickCoventryUnited Kingdom
| | - Benjamin Schuler
- Department of Biochemistry and Department of Physics, University of ZurichZurichSwitzerland
| | - Hamid Soleimaninejad
- Biological Optical Microscopy Platform (BOMP), University of MelbourneParkvilleAustralia
| | - Chun Tang
- College of Chemistry and Molecular Engineering, PKU-Tsinghua Center for Life Sciences, Beijing National Laboratory for Molecular Sciences, Peking UniversityBeijingChina
| | - Reza Vafabakhsh
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
| | - Don C Lamb
- Physical Chemistry, Department of Chemistry, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-UniversitätMünchenGermany
| | - Claus AM Seidel
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-UniversitätDüsseldorfGermany
| | - Shimon Weiss
- Department of Chemistry and Biochemistry, and Department of Physiology, University of California, Los AngelesLos AngelesUnited States
- Department of Physiology, CaliforniaNanoSystems Institute, University of California, Los AngelesLos AngelesUnited States
| |
Collapse
|
12
|
Lewinson O, Orelle C, Seeger MA. Structures of ABC transporters: handle with care. FEBS Lett 2020; 594:3799-3814. [PMID: 33098660 PMCID: PMC7756565 DOI: 10.1002/1873-3468.13966] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/22/2020] [Accepted: 10/15/2020] [Indexed: 12/11/2022]
Abstract
In the past two decades, the ATP‐binding cassette (ABC) transporters' field has undergone a structural revolution. The importance of structural biology to the development of the field of ABC transporters cannot be overstated, as the ensemble of structures not only revealed the architecture of ABC transporters but also shaped our mechanistic view of these remarkable molecular machines. Nevertheless, we advocate that the mechanistic interpretation of the structures is not trivial and should be carried out with prudence. Herein, we bring several examples of structures of ABC transporters that merit re‐interpretation via careful comparison to experimental data. We propose that it is of the upmost importance to place new structures within the context of the available experimental data.
Collapse
Affiliation(s)
- Oded Lewinson
- Department of Molecular Microbiology and the Rappaport Institute for Medical Sciences, Faculty of Medicine, The Technion-Israel Institute of Technology, Haifa, Israel
| | - Cédric Orelle
- CNRS, Molecular Microbiology and Structural Biochemistry (MMSB, UMR 5086), University of Lyon, Lyon, France
| | - Markus A Seeger
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| |
Collapse
|
13
|
Bisballe N, Laursen BW. What is Best Strategy for Water Soluble Fluorescence Dyes?-A Case Study Using Long Fluorescence Lifetime DAOTA Dyes*. Chemistry 2020; 26:15969-15976. [PMID: 32639046 DOI: 10.1002/chem.202002457] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/01/2020] [Indexed: 12/14/2022]
Abstract
The lipophilic nature of organic dyes complicates their effectiveness in aqueous solutions. In this work we investigate three different strategies for achieving water-solubility of the diazaoxatriangulenium (DAOTA+ ) chromophore: hydrophilic counter ions, aromatic sulfonation of the chromophore, and attachment of charged side chains. The long fluorescence lifetime (FLT, τf =20 ns) of DAOTA+ makes it a sensitive probe to analyze solvation and aggregation effects. Direct sulfonation of the chromophore was found to increase solubility drastically, but at the cost of greatly reduced quantum yields (QYs) due to enhanced non-radiative deactivation processes. The introduction of either cationic (4) or zwitterionic side chains (5), however, brings the FLT (τf =18 ns) and QY (ϕf =0.56) of the dye to the same level as the parent chromophore in acetonitrile. Time-resolved fluorescence spectroscopy also reveals a high resistance to aggregation and non-specific binding in a high loading of bovine serum albumin (BSA). The results clearly show that addition of charged flexible side chains is preferable to direct sulfonation of the chromophore core.
Collapse
Affiliation(s)
- Niels Bisballe
- Nano-Science Center, Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark
| | - Bo W Laursen
- Nano-Science Center, Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark
| |
Collapse
|
14
|
Gomes GNW, Krzeminski M, Namini A, Martin EW, Mittag T, Head-Gordon T, Forman-Kay JD, Gradinaru CC. Conformational Ensembles of an Intrinsically Disordered Protein Consistent with NMR, SAXS, and Single-Molecule FRET. J Am Chem Soc 2020; 142:15697-15710. [PMID: 32840111 PMCID: PMC9987321 DOI: 10.1021/jacs.0c02088] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Intrinsically disordered proteins (IDPs) have fluctuating heterogeneous conformations, which makes their structural characterization challenging. Although challenging, characterization of the conformational ensembles of IDPs is of great interest, since their conformational ensembles are the link between their sequences and functions. An accurate description of IDP conformational ensembles depends crucially on the amount and quality of the experimental data, how it is integrated, and if it supports a consistent structural picture. We used integrative modeling and validation to apply conformational restraints and assess agreement with the most common structural techniques for IDPs: Nuclear Magnetic Resonance (NMR) spectroscopy, Small-angle X-ray Scattering (SAXS), and single-molecule Förster Resonance Energy Transfer (smFRET). Agreement with such a diverse set of experimental data suggests that details of the generated ensembles can now be examined with a high degree of confidence. Using the disordered N-terminal region of the Sic1 protein as a test case, we examined relationships between average global polymeric descriptions and higher-moments of their distributions. To resolve apparent discrepancies between smFRET and SAXS inferences, we integrated SAXS data with NMR data and reserved the smFRET data for independent validation. Consistency with smFRET, which was not guaranteed a priori, indicates that, globally, the perturbative effects of NMR or smFRET labels on the Sic1 ensemble are minimal. Analysis of the ensembles revealed distinguishing features of Sic1, such as overall compactness and large end-to-end distance fluctuations, which are consistent with biophysical models of Sic1's ultrasensitive binding to its partner Cdc4. Our results underscore the importance of integrative modeling and validation in generating and drawing conclusions from IDP conformational ensembles.
Collapse
Affiliation(s)
- Gregory-Neal W Gomes
- Department of Physics, University of Toronto, Toronto, Ontario M5G 1X8, Canada.,Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | - Mickaël Krzeminski
- Molecular Medicine Program, Hospital for Sick Children, Toronto, Ontario M5S 1A8, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1X8, Canada
| | - Ashley Namini
- Department of Physics, University of Toronto, Toronto, Ontario M5G 1X8, Canada.,Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | - Erik W Martin
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, United States
| | - Tanja Mittag
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, United States
| | - Teresa Head-Gordon
- Departments of Chemistry, Bioengineering, Chemical and Biomolecular Engineering University of California, Berkeley, California 94720, United States
| | - Julie D Forman-Kay
- Molecular Medicine Program, Hospital for Sick Children, Toronto, Ontario M5S 1A8, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1X8, Canada
| | - Claudiu C Gradinaru
- Department of Physics, University of Toronto, Toronto, Ontario M5G 1X8, Canada.,Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| |
Collapse
|
15
|
Cavaco M, Pérez-Peinado C, Valle J, Silva RDM, Correia JDG, Andreu D, Castanho MARB, Neves V. To What Extent Do Fluorophores Bias the Biological Activity of Peptides? A Practical Approach Using Membrane-Active Peptides as Models. Front Bioeng Biotechnol 2020; 8:552035. [PMID: 33015016 PMCID: PMC7509492 DOI: 10.3389/fbioe.2020.552035] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 08/18/2020] [Indexed: 12/25/2022] Open
Abstract
The characterization of biologically active peptides relies heavily on the study of their efficacy, toxicity, mechanism of action, cellular uptake, or intracellular location, using both in vitro and in vivo studies. These studies frequently depend on the use of fluorescence-based techniques. Since most peptides are not intrinsically fluorescent, they are conjugated to a fluorophore. The conjugation may interfere with peptide properties, thus biasing the results. The selection of the most suitable fluorophore is highly relevant. Here, a comprehensive study with blood-brain barrier (BBB) peptide shuttles (PepH3 and PepNeg) and antimicrobial peptides (AMPs) (vCPP2319 and Ctn[15-34]), tested as anticancer peptides (ACPs), having different fluorophores, namely 5(6)-carboxyfluorescein (CF), rhodamine B (RhB), quasar 570 (Q570), or tide fluor 3 (TF3) attached is presented. The goal is the evaluation of the impact of the selected fluorophores on peptide performance, applying routinely used techniques to assess cytotoxicity/toxicity, secondary structure, BBB translocation, and cellular internalization. Our results show that some fluorophores significantly modulate peptide activity when compared with unlabeled peptides, being more noticeable in hydrophobic and charged fluorophores. This study highlights the need for a careful experimental design for fluorescently labeled molecules, such as peptides.
Collapse
Affiliation(s)
- Marco Cavaco
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Proteomics and Protein Chemistry Unit, Department of Experimental and Health Sciences, Pompeu Fabra University, Barcelona, Spain
| | - Clara Pérez-Peinado
- Proteomics and Protein Chemistry Unit, Department of Experimental and Health Sciences, Pompeu Fabra University, Barcelona, Spain
| | - Javier Valle
- Proteomics and Protein Chemistry Unit, Department of Experimental and Health Sciences, Pompeu Fabra University, Barcelona, Spain
| | - Rúben D. M. Silva
- Centro de Ciências e Tecnologias Nucleares and Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - João D. G. Correia
- Centro de Ciências e Tecnologias Nucleares and Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - David Andreu
- Proteomics and Protein Chemistry Unit, Department of Experimental and Health Sciences, Pompeu Fabra University, Barcelona, Spain
| | - Miguel A. R. B. Castanho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Vera Neves
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| |
Collapse
|
16
|
Isselstein M, Zhang L, Glembockyte V, Brix O, Cosa G, Tinnefeld P, Cordes T. Self-Healing Dyes-Keeping the Promise? J Phys Chem Lett 2020; 11:4462-4480. [PMID: 32401520 DOI: 10.1021/acs.jpclett.9b03833] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Self-healing dyes have emerged as a new promising class of fluorescent labels. They consist of two units, a fluorescent dye and a photostabilizer. The latter heals whenever the fluorescent dye is in danger of taking a reaction pathway toward photobleaching. We describe the underlying concepts and summarize the developmental history and state-of-the-art, including latest applications in high-resolution microscopy, live-cell, and single-molecule imaging. We further discuss remaining limitations, which are (i) lower photostabilization of most self-healing dyes when compared to solution additives, (ii) limited mechanistic understanding on the influence of the biochemical environment and molecular oxygen on self-healing, and (iii) the lack of cheap and facile bioconjugation strategies. Finally, we provide ideas on how to further advance self-healing dyes, show new data on redox blinking caused by double-stranded DNA, and highlight forthcoming work on intramolecular photostabilization of fluorescent proteins.
Collapse
Affiliation(s)
- Michael Isselstein
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152 Planegg-Martinsried, Germany
| | - Lei Zhang
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152 Planegg-Martinsried, Germany
| | - Viktorija Glembockyte
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, Haus E 81377 München, Germany
- Department of Chemistry and Quebec Centre for Applied Materials (QCAM), McGill University, 801 Sherbrooke Street W., H3A 0B8 Montreal, Quebec, Canada
| | - Oliver Brix
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152 Planegg-Martinsried, Germany
| | - Gonzalo Cosa
- Department of Chemistry and Quebec Centre for Applied Materials (QCAM), McGill University, 801 Sherbrooke Street W., H3A 0B8 Montreal, Quebec, Canada
| | - Philip Tinnefeld
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, Haus E 81377 München, Germany
| | - Thorben Cordes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152 Planegg-Martinsried, Germany
| |
Collapse
|
17
|
Bachman JL, Pavlich CI, Boley AJ, Marcotte EM, Anslyn EV. Synthesis of Carboxy ATTO 647N Using Redox Cycling for Xanthone Access. Org Lett 2020; 22:381-385. [PMID: 31825225 DOI: 10.1021/acs.orglett.9b03981] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A synthesis of the carbopyronine dye Carboxy ATTO 647N from simple materials is reported. This route proceeds in 11 forward steps from 3-bromoaniline with the key xanthone intermediate formed using a new oxidation methodology. The step utilizes an oxidation cycle with base, water, iodine, and more than doubles the yield of the standard permanganate oxidation methodology, accessing gram-scale quantities of this late-stage product. From this, Carboxy ATTO 647N was prepared in only four additional steps. This facile route to a complex fluorophore is expected to enable further studies in fluorescence imaging.
Collapse
Affiliation(s)
- James L Bachman
- Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Cyprian I Pavlich
- Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Alexander J Boley
- Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Edward M Marcotte
- Department of Molecular Biosciences , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Eric V Anslyn
- Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712 , United States
| |
Collapse
|
18
|
Dietz MS, Wehrheim SS, Harwardt MLIE, Niemann HH, Heilemann M. Competitive Binding Study Revealing the Influence of Fluorophore Labels on Biomolecular Interactions. NANO LETTERS 2019; 19:8245-8249. [PMID: 31621335 DOI: 10.1021/acs.nanolett.9b03736] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Fluorescence methods are important tools in modern biology. Direct labeling of biomolecules with a fluorophore might, however, change interaction surfaces. Here, we introduce a competitive binding assay in combination with fluorescence correlation spectroscopy that reports binding affinities of both labeled and unlabeled biomolecules to their binding target. We investigated how fluorophore labels at different positions of a DNA oligonucleotide affect hybridization to a complementary oligonucleotide and found dissociation constants varying within 2 orders of magnitude. We next demonstrated that placing a fluorophore label at position Leu280 in the protein ligand internalin B does not alter the binding affinity to the MET receptor tyrosine kinase, compared to unlabeled internalin B. Our approach is simple to implement and can be applied to investigate the influence of fluorophore labels in a large variety of biomolecular interactions.
Collapse
Affiliation(s)
- Marina S Dietz
- Single-Molecule Biophysics, Institute of Physical and Theoretical Chemistry , Goethe-University Frankfurt , Max-von-Laue-Straße 7 , 60438 Frankfurt/Main , Germany
| | - S Sophia Wehrheim
- Single-Molecule Biophysics, Institute of Physical and Theoretical Chemistry , Goethe-University Frankfurt , Max-von-Laue-Straße 7 , 60438 Frankfurt/Main , Germany
| | - Marie-Lena I E Harwardt
- Single-Molecule Biophysics, Institute of Physical and Theoretical Chemistry , Goethe-University Frankfurt , Max-von-Laue-Straße 7 , 60438 Frankfurt/Main , Germany
| | - Hartmut H Niemann
- Structural Biochemistry, Department of Chemistry , Bielefeld University , Universitätsstraße 25 , 33615 Bielefeld , Germany
| | - Mike Heilemann
- Single-Molecule Biophysics, Institute of Physical and Theoretical Chemistry , Goethe-University Frankfurt , Max-von-Laue-Straße 7 , 60438 Frankfurt/Main , Germany
| |
Collapse
|
19
|
Effect of substitution on the excited state photophysical and spectral properties of boron difluoride curcumin complex dye and their derivatives: A time dependent-DFT study. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2019; 199:111595. [PMID: 31470269 DOI: 10.1016/j.jphotobiol.2019.111595] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/30/2019] [Accepted: 08/14/2019] [Indexed: 12/30/2022]
Abstract
The optical, charge transport and electronic properties of boron difluoride curcumin (BFC) complex have been explored using the DFT (Density Functional Theory) method and B3LYP functional with the combination of 6-31 + G(d,p) as a basis set. The influence of substitution with various electron releasing and withdrawing groups on the above properties is analyzed and discussed in this work. The results reveal that the BFC complex on additional electron releasing substitution experiences redshifts in the optical transitions, and this is correlated with the dipole moment, NBO charges, HOMO-LUMO energy gap. Further, the absorption (λabs) and emission (λems) spectra of substituted and unsubstituted BFCs are calculated using Time-Dependent Density Functional Theory (TD-DFT). The results show that the electron releasing groups strongly influence the absorption and emission spectra of BFC. Electron releasing groups in BFC derivatives generate the wavelength shift (Bathochromic), but the electron-withdrawing groups in BFC don't affect the λabs and λems when compare to its original (parent) compound. The output of the research work strongly recommends that the amino, phenyl and N, N'-dimethylamino derivatives are potential candidates to act as fluorescent materials due to enhance the emission behavior of BFC and also can be used as an electron/charge transport material for organic light-emitting diodes (OLEDs).
Collapse
|
20
|
Abstract
AbstractThe dynamics of proteins in solution includes a variety of processes, such as backbone and side-chain fluctuations, interdomain motions, as well as global rotational and translational (i.e. center of mass) diffusion. Since protein dynamics is related to protein function and essential transport processes, a detailed mechanistic understanding and monitoring of protein dynamics in solution is highly desirable. The hierarchical character of protein dynamics requires experimental tools addressing a broad range of time- and length scales. We discuss how different techniques contribute to a comprehensive picture of protein dynamics, and focus in particular on results from neutron spectroscopy. We outline the underlying principles and review available instrumentation as well as related analysis frameworks.
Collapse
|
21
|
Elected to the Deutsche Akademie der Naturforscher Leopoldina: M. Sattler / Australian Museum Eureka Prizes: T. Maschmeyer and E. J. New / Alfred C. Egerton Gold Medal: K. Kohse-Höinghaus. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/anie.201810506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
22
|
Neues Mitglied der Deutschen Akademie der Naturforscher Leopoldina: Michael Sattler / Australian Museum Eureka Prizes: T. Maschmeyer und E. J. New / Alfred C. Egerton Gold Medal: K. Kohse-Höinghaus. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201810506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
23
|
Dutta B, Bhattacharjee B, Chowdhury J. Physics behind the Barrier to Internal Rotation of an Acetyl Chloride Molecule: A Combined Approach from Density Functional Theory, Car-Parrinello Molecular Dynamics, and Time-Resolved Wavelet Transform Theory. ACS OMEGA 2018; 3:6794-6803. [PMID: 31458850 PMCID: PMC6644580 DOI: 10.1021/acsomega.8b00316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/18/2018] [Indexed: 06/10/2023]
Abstract
The physics behind the barriers to internal rotation of acetyl chloride (AC) molecule has been reported. The AC molecule closely resembles the molecular structure of acetaldehyde; the only subtle difference is the presence of a heavy chlorine atom in place of the hydrogen atom of the aldehyde group for the latter. This paper aims to study the effect of substitution of the heavy chlorine atom on the barrier energetics of the AC molecule. The reason behind the barrier for the AC molecule has been estimated for the first time from the unified approach using barrier energetics, natural bond orbital, nuclear virial, and relaxation analyses using density functional theory, Car-Parrinello molecular dynamics, and wavelet transform theory. Complete analyses reveal the concomitant relaxations of both the in-plane Cmethyl-C1 and Cmethyl-H4 bonds toward understanding the origin of the barrier due to internal rotation for the AC molecule. The large negative value of "V 6" further suggests that both the abovementioned degrees of freedom are coupled with the -CH3 torsional vibration of the molecule. The coupling matrix (H 12) element has also been estimated. Time-resolved band stretching frequencies of Cmethyl-C1 and C1-Cl3 bonds of the AC molecule, as obtained from wavelet transformation analysis, primarily preclude the possibility of coupling between the C1-Cl3 bond and the torsional motion associated with the methyl group of the molecule.
Collapse
Affiliation(s)
- Bipan Dutta
- Department
of Physics, Sammilani Mahavidyalaya, E. M. Bypass, Baghajatin Station, Kolkata 700094, India
| | - Biplab Bhattacharjee
- Department of Chemistry and Department of Physics, Jadavpur University, 88, Raja S. C. Mallick Road, Kolkata 700032, India
| | - Joydeep Chowdhury
- Department of Chemistry and Department of Physics, Jadavpur University, 88, Raja S. C. Mallick Road, Kolkata 700032, India
| |
Collapse
|
24
|
Capturing dynamic conformational shifts in protein–ligand recognition using integrative structural biology in solution. Emerg Top Life Sci 2018; 2:107-119. [DOI: 10.1042/etls20170090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 03/18/2018] [Accepted: 03/20/2018] [Indexed: 11/17/2022]
Abstract
In recent years, a dynamic view of the structure and function of biological macromolecules is emerging, highlighting an essential role of dynamic conformational equilibria to understand molecular mechanisms of biological functions. The structure of a biomolecule, i.e. protein or nucleic acid in solution, is often best described as a dynamic ensemble of conformations, rather than a single structural state. Strikingly, the molecular interactions and functions of the biological macromolecule can then involve a shift between conformations that pre-exist in such an ensemble. Upon external cues, such population shifts of pre-existing conformations allow gradually relaying the signal to the downstream biological events. An inherent feature of this principle is conformational dynamics, where intrinsically disordered regions often play important roles to modulate the conformational ensemble. Unequivocally, solution-state NMR spectroscopy is a powerful technique to study the structure and dynamics of such biomolecules in solution. NMR is increasingly combined with complementary techniques, including fluorescence spectroscopy and small angle scattering. The combination of these techniques provides complementary information about the conformation and dynamics in solution and thus affords a comprehensive description of biomolecular functions and regulations. Here, we illustrate how an integrated approach combining complementary techniques can assess the structure and dynamics of proteins and protein complexes in solution.
Collapse
|
25
|
Vandenberk N, Barth A, Borrenberghs D, Hofkens J, Hendrix J. Evaluation of Blue and Far-Red Dye Pairs in Single-Molecule Förster Resonance Energy Transfer Experiments. J Phys Chem B 2018. [DOI: 10.1021/acs.jpcb.8b00108] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Niels Vandenberk
- Laboratory for Photochemistry and Spectroscopy, Division for Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Anders Barth
- Physical Chemistry, Department of Chemistry, Munich Center for Integrated Protein Science, Nanosystems Initiative Munich and Centre for Nanoscience, Ludwig-Maximilians-Universität München, 80539 Munich, Germany
| | - Doortje Borrenberghs
- Laboratory for Photochemistry and Spectroscopy, Division for Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Johan Hofkens
- Laboratory for Photochemistry and Spectroscopy, Division for Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Jelle Hendrix
- Laboratory for Photochemistry and Spectroscopy, Division for Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
- Dynamic Bioimaging Lab, Advanced Optical Microscopy Centre and Biomedical Research Institute, Hasselt University, Agoralaan C (BIOMED), Diepenbeek, B-3590, Belgium
| |
Collapse
|
26
|
Götz M, Wortmann P, Schmid S, Hugel T. Using Three-color Single-molecule FRET to Study the Correlation of Protein Interactions. J Vis Exp 2018. [PMID: 29443086 DOI: 10.3791/56896] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Single-molecule Förster resonance energy transfer (smFRET) has become a widely used biophysical technique to study the dynamics of biomolecules. For many molecular machines in a cell proteins have to act together with interaction partners in a functional cycle to fulfill their task. The extension of two-color to multi-color smFRET makes it possible to simultaneously probe more than one interaction or conformational change. This not only adds a new dimension to smFRET experiments but it also offers the unique possibility to directly study the sequence of events and to detect correlated interactions when using an immobilized sample and a total internal reflection fluorescence microscope (TIRFM). Therefore, multi-color smFRET is a versatile tool for studying biomolecular complexes in a quantitative manner and in a previously unachievable detail. Here, we demonstrate how to overcome the special challenges of multi-color smFRET experiments on proteins. We present detailed protocols for obtaining the data and for extracting kinetic information. This includes trace selection criteria, state separation, and the recovery of state trajectories from the noisy data using a 3D ensemble Hidden Markov Model (HMM). Compared to other methods, the kinetic information is not recovered from dwell time histograms but directly from the HMM. The maximum likelihood framework allows us to critically evaluate the kinetic model and to provide meaningful uncertainties for the rates. By applying our method to the heat shock protein 90 (Hsp90), we are able to disentangle the nucleotide binding and the global conformational changes of the protein. This allows us to directly observe the cooperativity between the two nucleotide binding pockets of the Hsp90 dimer.
Collapse
Affiliation(s)
- Markus Götz
- Institute of Physical Chemistry, University of Freiburg
| | | | - Sonja Schmid
- Institute of Physical Chemistry, University of Freiburg; Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology
| | - Thorsten Hugel
- Institute of Physical Chemistry, University of Freiburg;
| |
Collapse
|
27
|
Voith von Voithenberg L, Lamb DC. Single Pair Förster Resonance Energy Transfer: A Versatile Tool To Investigate Protein Conformational Dynamics. Bioessays 2018; 40. [DOI: 10.1002/bies.201700078] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 12/05/2017] [Indexed: 01/23/2023]
Affiliation(s)
- Lena Voith von Voithenberg
- Department Chemie; Center for Nanoscience (CeNS); Center for Integrated Protein Science Munich (CIPSM); Nanosystem Initiative Munich (NIM); Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 München Germany
- BIOSS Centre for Signalling Studies; Schänzlestr. 18 79104 Freiburg Germany
| | - Don C. Lamb
- Department Chemie; Center for Nanoscience (CeNS); Center for Integrated Protein Science Munich (CIPSM); Nanosystem Initiative Munich (NIM); Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 München Germany
| |
Collapse
|
28
|
Bap (Sil1) regulates the molecular chaperone BiP by coupling release of nucleotide and substrate. Nat Struct Mol Biol 2018; 25:90-100. [PMID: 29323281 DOI: 10.1038/s41594-017-0012-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 11/16/2017] [Indexed: 12/25/2022]
Abstract
BiP is the endoplasmic member of the Hsp70 family. BiP is regulated by several co-chaperones including the nucleotide-exchange factor (NEF) Bap (Sil1 in yeast). Bap is a two-domain protein. The interaction of the Bap C-terminal domain with the BiP ATPase domain is sufficient for its weak NEF activity. However, stimulation of the BiP ATPase activity requires full-length Bap, suggesting a complex interplay of these two factors. Here, single-molecule FRET experiments with mammalian proteins reveal that Bap affects the conformation of both BiP domains, including the lid subdomain, which is important for substrate binding. The largely unstructured Bap N-terminal domain promotes the substrate release from BiP. Thus, Bap is a conformational regulator affecting both nucleotide and substrate interactions. The preferential interaction with BiP in its ADP state places Bap at a late stage of the chaperone cycle, in which it coordinates release of substrate and ADP, thereby resetting BiP for ATP and substrate binding.
Collapse
|