1
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Roy M, Horovitz A. Distinguishing between concerted, sequential and barrierless conformational changes: Folding versus allostery. Curr Opin Struct Biol 2023; 83:102721. [PMID: 37922762 DOI: 10.1016/j.sbi.2023.102721] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/26/2023] [Indexed: 11/07/2023]
Abstract
Characterization of transition and intermediate states of reactions provides insights into their mechanisms and is often achieved through analysis of linear free energy relationships. Such an approach has been used extensively in protein folding studies but less so for analyzing allosteric transitions. Here, we point out analogies in ways to characterize pathways and intermediates in folding and allosteric transitions. Achieving an understanding of the mechanisms by which proteins undergo allosteric switching is important in many cases for obtaining insights into how they function.
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Affiliation(s)
- Mousam Roy
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Amnon Horovitz
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel.
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2
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Lavania A, Carpenter WB, Oltrogge LM, Perez D, Turnšek JB, Savage DF, Moerner WE. Exploring Masses and Internal Mass Distributions of Single Carboxysomes in Free Solution Using Fluorescence and Interferometric Scattering in an Anti-Brownian Trap. J Phys Chem B 2022; 126:8747-8759. [PMID: 36282790 PMCID: PMC9639131 DOI: 10.1021/acs.jpcb.2c05939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Carboxysomes are self-assembled bacterial microcompartments that facilitate carbon assimilation by colocalizing the enzymes of CO2 fixation within a protein shell. These microcompartments can be highly heterogeneous in their composition and filling, so measuring the mass and loading of an individual carboxysome would allow for better characterization of its assembly and function. To enable detailed and extended characterizations of single nanoparticles in solution, we recently demonstrated an improved interferometric scattering anti-Brownian electrokinetic (ISABEL) trap, which tracks the position of a single nanoparticle via its scattering of a near-infrared beam and applies feedback to counteract its Brownian motion. Importantly, the scattering signal can be related to the mass of nanoscale proteinaceous objects, whose refractive indices are well-characterized. We calibrate single-particle scattering cross-section measurements in the ISABEL trap and determine individual carboxysome masses in the 50-400 MDa range by analyzing their scattering cross sections with a core-shell model. We further investigate carboxysome loading by combining mass measurements with simultaneous fluorescence reporting from labeled internal components. This method may be extended to other biological objects, such as viruses or extracellular vesicles, and can be combined with orthogonal fluorescence reporters to achieve precise physical and chemical characterization of individual nanoscale biological objects.
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Affiliation(s)
- Abhijit
A. Lavania
- Department
of Chemistry, Stanford University, Stanford, California94305, United States,Department
of Applied Physics, Stanford University, Stanford, California94305, United States
| | - William B. Carpenter
- Department
of Chemistry, Stanford University, Stanford, California94305, United States
| | - Luke M. Oltrogge
- Department
of Molecular and Cell Biology, University
of California Berkeley, Berkeley, California94720, United States
| | - Davis Perez
- Department
of Chemistry, Stanford University, Stanford, California94305, United States
| | - Julia B. Turnšek
- Department
of Molecular and Cell Biology, University
of California Berkeley, Berkeley, California94720, United States
| | - David F. Savage
- Department
of Molecular and Cell Biology, University
of California Berkeley, Berkeley, California94720, United States
| | - W. E. Moerner
- Department
of Chemistry, Stanford University, Stanford, California94305, United States,Department
of Applied Physics, Stanford University, Stanford, California94305, United States,
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3
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Smith TM, Willardson BM. Mechanistic insights into protein folding by the eukaryotic chaperonin complex CCT. Biochem Soc Trans 2022; 50:1403-1414. [PMID: 36196890 PMCID: PMC9704529 DOI: 10.1042/bst20220591] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 11/17/2022]
Abstract
The cytosolic chaperonin CCT is indispensable to eukaryotic life, folding the cytoskeletal proteins actin and tubulin along with an estimated 10% of the remaining proteome. However, it also participates in human diseases such as cancer and viral infections, rendering it valuable as a potential therapeutic target. CCT consists of two stacked rings, each comprised of eight homologous but distinct subunits, that assists the folding of a remarkable substrate clientele that exhibits both broad diversity and specificity. Much of the work in recent years has been aimed at understanding the mechanisms of CCT substrate recognition and folding. These studies have revealed new binding sites and mechanisms by which CCT uses its distinctive subunit arrangement to fold structurally unrelated substrates. Here, we review recent structural insights into CCT-substrate interactions and place them into the broader context of CCT function and its implications for human health.
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Affiliation(s)
- Theresa M. Smith
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, U.S.A
| | - Barry M. Willardson
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, U.S.A
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4
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van Heerden B, Kruger T. Theoretical comparison of real-time feedback-driven single-particle tracking techniques. J Chem Phys 2022; 157:084111. [DOI: 10.1063/5.0096729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Real-time feedback-driven single-particle tracking is a technique that uses feedbackcontrol to enable single-molecule spectroscopy of freely diffusing particles in nativeor near-native environments. A number of different RT-FD-SPT approaches exist,and comparisons between methods based on experimental results are of limited usedue to differences in samples and setups. In this study, we used statistical calcu-lations and dynamical simulations to directly compare the performance of differentmethods. The methods considered were the orbital method, the Knight's Tour (gridscan) method and MINFLUX, and we considered both fluorescence-based and inter-ferometric scattering (iSCAT) approaches. There is a fundamental trade-off betweenprecision and speed, with the Knight's Tour method being able to track the fastestdiffusion but with low precision, and MINFLUX being the most precise but onlytracking slow diffusion. To compare iSCAT and fluorescence, different biologicalsamples were considered, including labeled and intrinsically fluorescent samples. Thesuccess of iSCAT as compared to fluorescence is strongly dependent on the particlesize and the density and photophysical properties of the fluorescent particles. Usinga wavelength for iSCAT that is negligibly absorbed by the tracked particle allowsan increased illumination intensity, which results in iSCAT providing better trackingfor most samples. This work highlights the fundamental aspects of performance inRT-FD-SPT and should assist with the selection of an appropriate method for a par-ticular application. The approach used can easily be extended to other RT-FD-SPTmethods.
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5
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van Heerden B, Vickers NA, Krüger TPJ, Andersson SB. Real-Time Feedback-Driven Single-Particle Tracking: A Survey and Perspective. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2107024. [PMID: 35758534 PMCID: PMC9308725 DOI: 10.1002/smll.202107024] [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: 11/14/2021] [Revised: 04/07/2022] [Indexed: 05/14/2023]
Abstract
Real-time feedback-driven single-particle tracking (RT-FD-SPT) is a class of techniques in the field of single-particle tracking that uses feedback control to keep a particle of interest in a detection volume. These methods provide high spatiotemporal resolution on particle dynamics and allow for concurrent spectroscopic measurements. This review article begins with a survey of existing techniques and of applications where RT-FD-SPT has played an important role. Each of the core components of RT-FD-SPT are systematically discussed in order to develop an understanding of the trade-offs that must be made in algorithm design and to create a clear picture of the important differences, advantages, and drawbacks of existing approaches. These components are feedback tracking and control, ranging from simple proportional-integral-derivative control to advanced nonlinear techniques, estimation to determine particle location from the measured data, including both online and offline algorithms, and techniques for calibrating and characterizing different RT-FD-SPT methods. Then a collection of metrics for RT-FD-SPT is introduced to help guide experimentalists in selecting a method for their particular application and to help reveal where there are gaps in the techniques that represent opportunities for further development. Finally, this review is concluded with a discussion on future perspectives in the field.
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Affiliation(s)
- Bertus van Heerden
- Department of Physics, University of Pretoria, Pretoria, 0002, South Africa
- Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa
| | - Nicholas A Vickers
- Department of Mechanical Engineering, Boston University, Boston, MA, 02215, USA
| | - Tjaart P J Krüger
- Department of Physics, University of Pretoria, Pretoria, 0002, South Africa
- Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa
| | - Sean B Andersson
- Department of Mechanical Engineering, Boston University, Boston, MA, 02215, USA
- Division of Systems Engineering, Boston University, Boston, MA, 02215, USA
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6
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Kelly JJ, Tranter D, Pardon E, Chi G, Kramer H, Happonen L, Knee KM, Janz JM, Steyaert J, Bulawa C, Paavilainen VO, Huiskonen JT, Yue WW. Snapshots of actin and tubulin folding inside the TRiC chaperonin. Nat Struct Mol Biol 2022; 29:420-429. [PMID: 35449234 PMCID: PMC9113939 DOI: 10.1038/s41594-022-00755-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 03/01/2022] [Indexed: 01/16/2023]
Abstract
The integrity of a cell's proteome depends on correct folding of polypeptides by chaperonins. The chaperonin TCP-1 ring complex (TRiC) acts as obligate folder for >10% of cytosolic proteins, including he cytoskeletal proteins actin and tubulin. Although its architecture and how it recognizes folding substrates are emerging from structural studies, the subsequent fate of substrates inside the TRiC chamber is not defined. We trapped endogenous human TRiC with substrates (actin, tubulin) and cochaperone (PhLP2A) at different folding stages, for structure determination by cryo-EM. The already-folded regions of client proteins are anchored at the chamber wall, positioning unstructured regions toward the central space to achieve their native fold. Substrates engage with different sections of the chamber during the folding cycle, coupled to TRiC open-and-close transitions. Further, the cochaperone PhLP2A modulates folding, acting as a molecular strut between substrate and TRiC chamber. Our structural snapshots piece together an emerging model of client protein folding within TRiC.
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Affiliation(s)
- John J Kelly
- Centre for Medicines Discovery, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Dale Tranter
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, Helsinki, Finland
| | - Els Pardon
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
| | - Gamma Chi
- Centre for Medicines Discovery, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Holger Kramer
- Biological Mass Spectrometry and Proteomics Facility, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Lotta Happonen
- Division of Infection Medicine, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Kelly M Knee
- Pfizer Rare Disease Research Unit, Worldwide Research and Development, Pfizer Inc., Cambridge, MA, USA
| | - Jay M Janz
- Pfizer Rare Disease Research Unit, Worldwide Research and Development, Pfizer Inc., Cambridge, MA, USA
| | - Jan Steyaert
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
| | - Christine Bulawa
- Pfizer Rare Disease Research Unit, Worldwide Research and Development, Pfizer Inc., Cambridge, MA, USA
| | - Ville O Paavilainen
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, Helsinki, Finland
| | - Juha T Huiskonen
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, Helsinki, Finland.
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.
- Division of Structural Biology, Wellcome Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford, UK.
| | - Wyatt W Yue
- Centre for Medicines Discovery, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
- Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, UK.
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7
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Sielaff H, Dienerowitz F, Dienerowitz M. Single-molecule FRET combined with electrokinetic trapping reveals real-time enzyme kinetics of individual F-ATP synthases. NANOSCALE 2022; 14:2327-2336. [PMID: 35084006 DOI: 10.1039/d1nr05754e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Single-molecule Förster resonance energy transfer (smFRET) is a key technique to observe conformational changes in molecular motors and to access the details of single-molecule static and dynamic disorder during catalytic processes. However, studying freely diffusing molecules in solution is limited to a few tens of milliseconds, while surface attachment often bears the risk to restrict their natural motion. In this paper we combine smFRET and electrokinetic trapping (ABEL trap) to non-invasively hold single FOF1-ATP synthases for up to 3 s within the detection volume, thereby extending the observation time by a factor of 10 as compared to Brownian diffusion without surface attachment. In addition, we are able to monitor complete reaction cycles and to selectively trap active molecules based on their smFRET signal, thus speeding up the data acquisition process. We demonstrate the capability of our method to study the dynamics of single molecules by recording the ATP-hydrolysis driven rotation of individual FOF1-ATP synthase molecules over numerous reaction cycles and extract their kinetic rates. We argue that our method is not limited to motor proteins. Instead, it can be applied to monitor conformational changes with millisecond time resolution for a wide range of enzymes, thereby making it a versatile tool for studying protein dynamics.
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Affiliation(s)
- Hendrik Sielaff
- Department of Chemistry, Centre for BioImaging Sciences, National University of Singapore, 14 Science Drive 4, 117557 Singapore, Singapore
| | - Frank Dienerowitz
- Ernst-Abbe-Hochschule Jena, University of Applied Sciences, Carl-Zeiss-Promenade 2, 07745 Jena, Germany
| | - Maria Dienerowitz
- Single-Molecule Microscopy Group, Universitätsklinikum Jena, Nonnenplan 2-4, 07743 Jena, Germany.
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8
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Wilson H, Wang Q. Joint Detection of Change Points in Multichannel Single-Molecule Measurements. J Phys Chem B 2021; 125:13425-13435. [PMID: 34870418 DOI: 10.1021/acs.jpcb.1c08869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Recent developments in single-molecule measurement technology have expanded the capability to measure multiple parameters. These emergent modalities provide more holistic observations of complex biomolecular processes and call for new analysis methods to detect state changes in multichannel data. Here we develop an algorithm called MULLR (MUlti-channel Log-Likelihood Ratio test) to jointly identify change points in multichannel single-molecule measurements. MULLR is an extension of the popular single-channel implementation for change point detection based on a binary segmentation and log-likelihood ratio test framework. We validate the algorithm on simulated data and characterize the power of detection and false positive rate. We show that MULLR can identify change points in experimental multichannel data and naturally works with different noise statistics and time resolutions across channels. Further, we quantify the benefit of MULLR compared to single-channel analysis. We envision that the MULLR algorithm will be useful to a range of multiparameter single-molecule measurements.
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Affiliation(s)
- Hugh Wilson
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08540, United States
| | - Quan Wang
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08540, United States
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9
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CryoEM reveals the stochastic nature of individual ATP binding events in a group II chaperonin. Nat Commun 2021; 12:4754. [PMID: 34362932 PMCID: PMC8346469 DOI: 10.1038/s41467-021-25099-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/21/2021] [Indexed: 12/05/2022] Open
Abstract
Chaperonins are homo- or hetero-oligomeric complexes that use ATP binding and hydrolysis to facilitate protein folding. ATP hydrolysis exhibits both positive and negative cooperativity. The mechanism by which chaperonins coordinate ATP utilization in their multiple subunits remains unclear. Here we use cryoEM to study ATP binding in the homo-oligomeric archaeal chaperonin from Methanococcus maripaludis (MmCpn), consisting of two stacked rings composed of eight identical subunits each. Using a series of image classification steps, we obtained different structural snapshots of individual chaperonins undergoing the nucleotide binding process. We identified nucleotide-bound and free states of individual subunits in each chaperonin, allowing us to determine the ATP occupancy state of each MmCpn particle. We observe distinctive tertiary and quaternary structures reflecting variations in nucleotide occupancy and subunit conformations in each chaperonin complex. Detailed analysis of the nucleotide distribution in each MmCpn complex indicates that individual ATP binding events occur in a statistically random manner for MmCpn, both within and across the rings. Our findings illustrate the power of cryoEM to characterize a biochemical property of multi-subunit ligand binding cooperativity at the individual particle level. The mechanism by which chaperonins coordinate ATP utilization in their multiple subunits remains unclear. Here, the authors employ an approach that uses cryo-EM single particle analysis to track the number and distribution of nucleotides bound to each subunit in the homo-oligomeric MmCpn archaeal chaperonin complex and observe that ATP binds in a statistically random manner to MmCpn both within a ring and across the rings, which shows that there is no cooperativity in ATP binding to archaeal group II chaperonins under the conditions used in this study.
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10
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White DS, Chowdhury S, Idikuda V, Zhang R, Retterer ST, Goldsmith RH, Chanda B. cAMP binding to closed pacemaker ion channels is non-cooperative. Nature 2021; 595:606-610. [PMID: 34194042 PMCID: PMC8513821 DOI: 10.1038/s41586-021-03686-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 06/02/2021] [Indexed: 12/17/2022]
Abstract
Electrical activity in the brain and heart depends on rhythmic generation of action potentials by pacemaker ion channels (HCN) whose activity is regulated by cAMP binding1. Previous work has uncovered evidence for both positive and negative cooperativity in cAMP binding2,3, but such bulk measurements suffer from limited parameter resolution. Efforts to eliminate this ambiguity using single-molecule techniques have been hampered by the inability to directly monitor binding of individual ligand molecules to membrane receptors at physiological concentrations. Here we overcome these challenges using nanophotonic zero-mode waveguides4 to directly resolve binding dynamics of individual ligands to multimeric HCN1 and HCN2 ion channels. We show that cAMP binds independently to all four subunits when the pore is closed, despite a subsequent conformational isomerization to a flip state at each site. The different dynamics in binding and isomerization are likely to underlie physiologically distinct responses of each isoform to cAMP5 and provide direct validation of the ligand-induced flip-state model6-9. This approach for observing stepwise binding in multimeric proteins at physiologically relevant concentrations can directly probe binding allostery at single-molecule resolution in other intact membrane proteins and receptors.
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Affiliation(s)
- David S White
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Sandipan Chowdhury
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Vinay Idikuda
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA
- Center for Investigation of Membrane Excitability Diseases, Department of Anesthesiology, Washington University School of Medicine, St Louis, MO, USA
| | - Ruohan Zhang
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Scott T Retterer
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | | | - Baron Chanda
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA.
- Center for Investigation of Membrane Excitability Diseases, Department of Anesthesiology, Washington University School of Medicine, St Louis, MO, USA.
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11
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Dienerowitz M, Howard JAL, Quinn SD, Dienerowitz F, Leake MC. Single-molecule FRET dynamics of molecular motors in an ABEL trap. Methods 2021; 193:96-106. [PMID: 33571667 DOI: 10.1016/j.ymeth.2021.01.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/22/2021] [Accepted: 01/29/2021] [Indexed: 02/07/2023] Open
Abstract
Single-molecule Förster resonance energy transfer (smFRET) of molecular motors provides transformative insights into their dynamics and conformational changes both at high temporal and spatial resolution simultaneously. However, a key challenge of such FRET investigations is to observe a molecule in action for long enough without restricting its natural function. The Anti-Brownian ELectrokinetic Trap (ABEL trap) sets out to combine smFRET with molecular confinement to enable observation times of up to several seconds while removing any requirement of tethered surface attachment of the molecule in question. In addition, the ABEL trap's inherent ability to selectively capture FRET active molecules accelerates the data acquisition process. In this work we exemplify the capabilities of the ABEL trap in performing extended timescale smFRET measurements on the molecular motor Rep, which is crucial for removing protein blocks ahead of the advancing DNA replication machinery and for restarting stalled DNA replication. We are able to monitor single Rep molecules up to 6 seconds with sub-millisecond time resolution capturing multiple conformational switching events during the observation time. Here we provide a step-by-step guide for the rational design, construction and implementation of the ABEL trap for smFRET detection of Rep in vitro. We include details of how to model the electric potential at the trap site and use Hidden Markov analysis of the smFRET trajectories.
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Affiliation(s)
- Maria Dienerowitz
- Single-Molecule Microscopy Group, Universitätsklinikum Jena, Nonnenplan 2 - 4, 07743 Jena, Germany.
| | - Jamieson A L Howard
- Department of Physics, University of York, Heslington, York YO10 5DD, UK; Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Steven D Quinn
- Department of Physics, University of York, Heslington, York YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK
| | - Frank Dienerowitz
- Ernst-Abbe-Hochschule Jena, University of Applied Sciences, Carl-Zeiss-Promenade 2, 07745 Jena, Germany
| | - Mark C Leake
- Department of Physics, University of York, Heslington, York YO10 5DD, UK; Department of Biology, University of York, Heslington, York YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK
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12
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Proteotoxicity: A Fatal Consequence of Environmental Pollutants-Induced Impairments in Protein Clearance Machinery. J Pers Med 2021; 11:jpm11020069. [PMID: 33503824 PMCID: PMC7912547 DOI: 10.3390/jpm11020069] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/20/2021] [Accepted: 01/22/2021] [Indexed: 02/08/2023] Open
Abstract
A tightly regulated protein quality control (PQC) system maintains a healthy balance between correctly folded and misfolded protein species. This PQC system work with the help of a complex network comprised of molecular chaperones and proteostasis. Any intruder, especially environmental pollutants, disrupt the PQC network and lead to PQCs disruption, thus generating damaged and infectious protein. These misfolded/unfolded proteins are linked to several diseases such as Parkinson's disease, Alzheimer's disease, Huntington's disease, and cataracts. Numerous studies on proteins misfolding and disruption of PQCs by environmental pollutants highlight the necessity of detailed knowledge. This review represents the PQCs network and environmental pollutants' impact on the PQC network, especially through the protein clearance system.
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13
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Wang H, Song S, Cheng H, Tan YW. State-of-the-Art Technologies for Understanding Brassinosteroid Signaling Networks. Int J Mol Sci 2020; 21:E8179. [PMID: 33142942 PMCID: PMC7662629 DOI: 10.3390/ijms21218179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 01/02/2023] Open
Abstract
Brassinosteroids, the steroid hormones of plants, control physiological and developmental processes through its signaling pathway. The major brassinosteroid signaling network components, from the receptor to transcription factors, have been identified in the past two decades. The development of biotechnologies has driven the identification of novel brassinosteroid signaling components, even revealing several crosstalks between brassinosteroid and other plant signaling pathways. Herein, we would like to summarize the identification and improvement of several representative brassinosteroid signaling components through the development of new technologies, including brassinosteroid-insensitive 1 (BRI1), BRI1-associated kinase 1 (BAK1), BR-insensitive 2 (BIN2), BRI1 kinase inhibitor 1 (BKI1), BRI1-suppressor 1 (BSU1), BR signaling kinases (BSKs), BRI1 ethyl methanesulfonate suppressor 1 (BES1), and brassinazole resistant 1 (BZR1). Furthermore, improvement of BR signaling knowledge, such as the function of BKI1, BES1 and its homologous through clustered regularly interspaced short palindromic repeats (CRISPR), the regulation of BIN2 through single-molecule methods, and the new in vivo interactors of BIN2 identified by proximity labeling are described. Among these technologies, recent advanced methods proximity labeling and single-molecule methods will be reviewed in detail to provide insights to brassinosteroid and other phytohormone signaling pathway studies.
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Affiliation(s)
- Haijiao Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475001, China;
| | - Song Song
- Department of Basic Courses, Zhejiang University of Water Resources and Electric Power, Hangzhou 310018, China;
| | - Huaqiang Cheng
- State Key Laboratory of Surface Physics, Multiscale Research Institute of Complex Systems, Department of Physics, Fudan University, Shanghai 200433, China;
| | - Yan-Wen Tan
- State Key Laboratory of Surface Physics, Multiscale Research Institute of Complex Systems, Department of Physics, Fudan University, Shanghai 200433, China;
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14
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Squires A, Lavania AA, Dahlberg PD, Moerner WE. Interferometric Scattering Enables Fluorescence-Free Electrokinetic Trapping of Single Nanoparticles in Free Solution. NANO LETTERS 2019; 19:4112-4117. [PMID: 31117762 PMCID: PMC6604838 DOI: 10.1021/acs.nanolett.9b01514] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/13/2019] [Indexed: 05/05/2023]
Abstract
Anti-Brownian traps confine single particles in free solution by closed-loop feedback forces that directly counteract Brownian motion. Extended-duration measurements on trapped objects allow detailed characterization of photophysical and transport properties as well as observation of infrequent or rare dynamics. However, this approach has been generally limited to particles that can be tracked by fluorescence emission. Here we present the Interferometric Scattering Anti-Brownian ELectrokinetic (ISABEL) trap, which uses interferometric scattering rather than fluorescence to monitor particle position. By decoupling the ability to track (and therefore trap) a particle from collection of its spectroscopic data, the ISABEL trap enables confinement and extended study of single particles that do not fluoresce, only weakly fluoresce, or exhibit intermittent fluorescence or photobleaching. This new technique significantly expands the range of nanoscale objects that may be investigated at the single-particle level in free solution.
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Affiliation(s)
- Allison
H. Squires
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Abhijit A. Lavania
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
- Department
of Applied Physics, Stanford University, Stanford, California 94305, United States
| | - Peter D. Dahlberg
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - W. E. Moerner
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
- Department
of Applied Physics, Stanford University, Stanford, California 94305, United States
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15
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Gruber R, Horovitz A. Unpicking allosteric mechanisms of homo-oligomeric proteins by determining their successive ligand binding constants. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0176. [PMID: 29735730 DOI: 10.1098/rstb.2017.0176] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2018] [Indexed: 11/12/2022] Open
Abstract
Advances in native mass spectrometry and single-molecule techniques have made it possible in recent years to determine the values of successive ligand binding constants for large multi-subunit proteins. Given these values, it is possible to distinguish between different allosteric mechanisms and, thus, obtain insights into how various bio-molecular machines work. Here, we describe for ring-shaped homo-oligomers, in particular, how the relationship between the values of successive ligand binding constants is diagnostic for concerted, sequential and probabilistic allosteric mechanisms.This article is part of a discussion meeting issue 'Allostery and molecular machines'.
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Affiliation(s)
- Ranit Gruber
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Amnon Horovitz
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
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16
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Gestaut D, Limatola A, Joachimiak L, Frydman J. The ATP-powered gymnastics of TRiC/CCT: an asymmetric protein folding machine with a symmetric origin story. Curr Opin Struct Biol 2019; 55:50-58. [PMID: 30978594 DOI: 10.1016/j.sbi.2019.03.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 03/04/2019] [Indexed: 10/27/2022]
Abstract
The eukaryotic chaperonin TRiC/CCT is a large hetero-oligomeric complex that plays an essential role assisting cellular protein folding and suppressing protein aggregation. It consists of two rings, and each composed of eight different subunits; non-native polypeptides bind and fold in an ATP-dependent manner within their central chamber. Here, we review recent advances in our understanding of TRiC structure and mechanism enabled by application of hybrid structural methods including the integration of cryo-electron microscopy with distance constraints from crosslinking mass spectrometry. These new insights are revealing how the different TRiC/CCT subunits create asymmetry in its ATP-driven conformational cycle and its interaction with non-native polypeptides, which ultimately underlie its unique ability to fold proteins that cannot be folded by other chaperones.
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Affiliation(s)
- Daniel Gestaut
- Department of Biology and Genetics, Stanford University, Stanford, CA 94305-5430, USA
| | - Antonio Limatola
- Department of Biology and Genetics, Stanford University, Stanford, CA 94305-5430, USA
| | - Lukasz Joachimiak
- Department of Biology and Genetics, Stanford University, Stanford, CA 94305-5430, USA
| | - Judith Frydman
- Department of Biology and Genetics, Stanford University, Stanford, CA 94305-5430, USA.
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17
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Croop B, Zhang C, Lim Y, Gelfand RM, Han KY. Recent advancement of light-based single-molecule approaches for studying biomolecules. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2019; 11:e1445. [PMID: 30724484 DOI: 10.1002/wsbm.1445] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 12/01/2018] [Accepted: 01/08/2019] [Indexed: 12/27/2022]
Abstract
Recent advances in single-molecule techniques have led to new discoveries in analytical chemistry, biophysics, and medicine. Understanding the structure and behavior of single biomolecules provides a wealth of information compared to studying large ensembles. However, developing single-molecule techniques is challenging and requires advances in optics, engineering, biology, and chemistry. In this paper, we will review the state of the art in single-molecule applications with a focus over the last few years of development. The advancements covered will mainly include light-based in vitro methods, and we will discuss the fundamentals of each with a focus on the platforms themselves. We will also summarize their limitations and current and future applications to the wider biological and chemical fields. This article is categorized under: Laboratory Methods and Technologies > Imaging Laboratory Methods and Technologies > Macromolecular Interactions, Methods Analytical and Computational Methods > Analytical Methods.
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Affiliation(s)
- Benjamin Croop
- CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida
| | - Chenyi Zhang
- CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida
| | - Youngbin Lim
- Department of Bioengineering, Stanford University, Stanford, California
| | - Ryan M Gelfand
- CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida
| | - Kyu Young Han
- CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida
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18
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Foote AK, Manger LH, Holden MR, Margittai M, Goldsmith RH. Time-resolved multirotational dynamics of single solution-phase tau proteins reveals details of conformational variation. Phys Chem Chem Phys 2019; 21:1863-1871. [PMID: 30632561 PMCID: PMC6449148 DOI: 10.1039/c8cp06971a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Intrinsically disordered proteins (IDPs) are crucial to many cellular processes and have been linked to neurodegenerative diseases. Single molecules of tau, an IDP associated with Alzheimer's disease, are trapped in solution using a microfluidic device, and a time-resolved fluorescence anisotropy decay is recorded for each molecule. Multiple rotational components are resolved and a novel k-means algorithm is used to sort the molecules into two families of conformations. Differences in rotational dynamics suggest a change in the rigidity and steric hindrance surrounding a sequence (306VQIVYK311) which is central to paired helical filament formation. This single-molecule approach can be applied to other IDPs to resolve heterogeneous populations and underlying differences in conformational dynamics.
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Affiliation(s)
- Alexander K Foote
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, WI 53706, USA.
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19
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Abstract
The eukaryotic group II chaperonin TRiC/CCT assists the folding of 10% of cytosolic proteins including many key structural and regulatory proteins. TRiC plays an essential role in maintaining protein homeostasis, and dysfunction of TRiC is closely related to human diseases including cancer and neurodegenerative diseases. TRiC consists of eight paralogous subunits, each of which plays a specific role in the assembly, allosteric cooperativity, and substrate recognition and folding of this complex macromolecular machine. TRiC-mediated substrate folding is regulated through its ATP-driven conformational changes. In recent years, progresses have been made on the structure, subunit arrangement, conformational cycle, and substrate folding of TRiC. Additionally, accumulating evidences also demonstrate the linkage between TRiC oligomer or monomer and diseases. In this review, we focus on the TRiC structure itself, TRiC assisted substrate folding, TRiC and disease, and the potential therapeutic application of TRiC in various diseases.
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Affiliation(s)
- Mingliang Jin
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Caixuan Liu
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Wenyu Han
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Yao Cong
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China.
- Shanghai Science Research Center, Chinese Academy of Sciences, Shanghai, China.
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20
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Yang HY, Moerner WE. Resolving Mixtures in Solution by Single-Molecule Rotational Diffusivity. NANO LETTERS 2018; 18:5279-5287. [PMID: 30001492 DOI: 10.1021/acs.nanolett.8b02280] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Sensing the size of individual molecules in an ensemble has proven to be a powerful tool to investigate biomolecular interactions and association-dissociation processes. In biologically relevant solution environments, molecular size is often sensed by translational or rotational diffusivity. The rotational diffusivity is more sensitive to the size and conformation of the molecules as it is inversely proportional to the cube of the hydrodynamic radius, as opposed to the inverse linear dependence of the translational diffusion coefficient. Single-molecule rotational diffusivity has been measured with time-resolved fluorescence anisotropy decay, but the ability to sense different sizes has been restricted by the limited number of photons available or has required surface attachment to observe each molecule longer, and the attachment may be perturbative. To address these limitations, we show how to measure and monitor single-molecule rotational diffusivity by combining the solution-phase Anti-Brownian ELectrokinetic (ABEL) trap and maximum likelihood analysis of time-resolved fluorescence anisotropy based on the information inherent in each detected photon. We demonstrate this approach by resolving a mixture of single- and double-stranded fluorescently labeled DNA molecules at equilibrium, freely rotating in a native solution environment. The rotational diffusivity, fluorescence brightness and lifetime, and initial and steady-state anisotropy are simultaneously determined for each trapped single DNA molecule. The time resolution and precision of this method are analyzed using statistical signal analysis and simulations. We present key parameters that define the usefulness of a particular fluorescent label for extracting molecular size information from single-molecule rotational diffusivity measurements.
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Affiliation(s)
- Hsiang-Yu Yang
- Department of Chemistry , Stanford University , Stanford , California 94305-4401 , United States
| | - W E Moerner
- Department of Chemistry , Stanford University , Stanford , California 94305-4401 , United States
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21
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Wang Q, Serban AJ, Wachter RM, Moerner WE. Single-molecule diffusometry reveals the nucleotide-dependent oligomerization pathways of Nicotiana tabacum Rubisco activase. J Chem Phys 2018. [PMID: 29604852 DOI: 10.1101/191742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023] Open
Abstract
Oligomerization plays an important role in the function of many proteins, but a quantitative picture of the oligomer distribution has been difficult to obtain using existing techniques. Here we describe a method that combines sub-stoichiometric labeling and recently developed single-molecule diffusometry to measure the size distribution of oligomers under equilibrium conditions in solution, one molecule at a time. We use this technique to characterize the oligomerization behavior of Nicotiana tabacum (Nt) Rubisco activase (Nt-Rca), a chaperone-like AAA-plus ATPase essential in regulating carbon fixation during photosynthesis. We directly observed monomers, dimers, and a tetramer/hexamer mixture and extracted their fractional abundance as a function of protein concentration. We show that the oligomerization pathway of Nt-Rca is nucleotide dependent: ATPγS binding strongly promotes tetramer/hexamer formation from dimers and results in a preferred tetramer/hexamer population for concentrations in the 1-10 μM range. Furthermore, we directly observed dynamic assembly and disassembly processes of single complexes in real time and from there estimated the rate of subunit exchange to be ∼0.1 s-1 with ATPγS. On the other hand, ADP binding destabilizes Rca complexes by enhancing the rate of subunit exchange by >2 fold. These observations provide a quantitative starting point to elucidate the structure-function relations of Nt-Rca complexes. We envision the method to fill a critical gap in defining and quantifying protein assembly pathways in the small-oligomer regime.
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Affiliation(s)
- Quan Wang
- Department of Chemistry, Stanford University, Stanford, California 94035, USA
| | - Andrew J Serban
- School of Molecular Sciences and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85281, USA
| | - Rebekka M Wachter
- School of Molecular Sciences and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85281, USA
| | - W E Moerner
- Department of Chemistry, Stanford University, Stanford, California 94035, USA
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22
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Wang Q, Serban AJ, Wachter RM, Moerner WE. Single-molecule diffusometry reveals the nucleotide-dependent oligomerization pathways of Nicotiana tabacum Rubisco activase. J Chem Phys 2018; 148:123319. [PMID: 29604852 DOI: 10.1063/1.5005930] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Oligomerization plays an important role in the function of many proteins, but a quantitative picture of the oligomer distribution has been difficult to obtain using existing techniques. Here we describe a method that combines sub-stoichiometric labeling and recently developed single-molecule diffusometry to measure the size distribution of oligomers under equilibrium conditions in solution, one molecule at a time. We use this technique to characterize the oligomerization behavior of Nicotiana tabacum (Nt) Rubisco activase (Nt-Rca), a chaperone-like AAA-plus ATPase essential in regulating carbon fixation during photosynthesis. We directly observed monomers, dimers, and a tetramer/hexamer mixture and extracted their fractional abundance as a function of protein concentration. We show that the oligomerization pathway of Nt-Rca is nucleotide dependent: ATPγS binding strongly promotes tetramer/hexamer formation from dimers and results in a preferred tetramer/hexamer population for concentrations in the 1-10 μM range. Furthermore, we directly observed dynamic assembly and disassembly processes of single complexes in real time and from there estimated the rate of subunit exchange to be ∼0.1 s-1 with ATPγS. On the other hand, ADP binding destabilizes Rca complexes by enhancing the rate of subunit exchange by >2 fold. These observations provide a quantitative starting point to elucidate the structure-function relations of Nt-Rca complexes. We envision the method to fill a critical gap in defining and quantifying protein assembly pathways in the small-oligomer regime.
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Affiliation(s)
- Quan Wang
- Department of Chemistry, Stanford University, Stanford, California 94035, USA
| | - Andrew J Serban
- School of Molecular Sciences and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85281, USA
| | - Rebekka M Wachter
- School of Molecular Sciences and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85281, USA
| | - W E Moerner
- Department of Chemistry, Stanford University, Stanford, California 94035, USA
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23
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Chang CC, Edwald E, Veatch S, Steel DG, Gafni A. Interactions of amyloid-β peptides on lipid bilayer studied by single molecule imaging and tracking. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1616-1624. [PMID: 29580771 DOI: 10.1016/j.bbamem.2018.03.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/16/2018] [Accepted: 03/17/2018] [Indexed: 12/17/2022]
Abstract
The amyloid-β peptides (Aβ40 and Aβ42) feature prominently in the synaptic dysfunction and neuronal loss associated with Alzheimer's disease (AD). This has been proposed to be due either to interactions between Aβ and cell surface receptors affecting cell signaling, or to the formation of calcium-permeable channels in the membrane that disrupt calcium homeostasis. In both mechanisms the cell membrane is the primary cellular structure with which Aβ interacts. Aβ concentrations in human bodily fluids are very low (pM-nM) rendering studies of the size, composition, cellular binding sites and mechanism of action of the oligomers formed in vivo very challenging. Most studies, therefore, have utilized Aβ oligomers prepared at micromolar peptide concentrations, where Aβ forms oligomeric species which possess easily observable cell toxicity. Such toxicity has not been observed when nM concentrations of peptide are used in the experiment highlighting the importance of employing physiologically relevant peptide concentrations for the results to be of biological significance. In this paper single-molecule microscopy was used to monitor Aβ oligomer formation and diffusion on a supported lipid bilayer at nanomolar peptide concentrations. Aβ monomers, the dominant species in solution, tightly associate with the membrane and are highly mobile whereas trimers and higher-order oligomers are largely immobile. Aβ dimers exist in a mixture of mobile and immobile states. Oligomer growth on the membrane is more rapid for Aβ40 than for the more amyloidogenic Aβ42 but is largely inhibited for a 1:1 Aβ40:Aβ42 mixture. The mechanism underlying these Aβ40-Aβ42 interactions may feature in Alzheimer's pathology.
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Affiliation(s)
- Chun-Chieh Chang
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Elin Edwald
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sarah Veatch
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Duncan G Steel
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA; Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA; Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ari Gafni
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
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24
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Shoemark DK, Sessions RB, Brancaccio A, Bigotti MG. Intraring allostery controls the function and assembly of a hetero-oligomeric class II chaperonin. FASEB J 2018; 32:2223-2234. [PMID: 29233859 PMCID: PMC5983026 DOI: 10.1096/fj.201701061r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Class II chaperonins are essential multisubunit complexes that aid the folding of nonnative proteins in the cytosol of archaea and eukarya. They use energy derived from ATP to drive a series of structural rearrangements that enable polypeptides to fold within their central cavity. These events are regulated by an elaborate allosteric mechanism in need of elucidation. We employed mutagenesis and experimental analysis in concert with in silico molecular dynamics simulations and interface-binding energy calculations to investigate the class II chaperonin from Thermoplasma acidophilum. Here we describe the effects on the asymmetric allosteric mechanism and on hetero-oligomeric complex formation in a panel of mutants in the ATP-binding pocket of the α and β subunits. Our observations reveal a potential model for a nonconcerted folding mechanism optimized for protecting and refolding a range of nonnative substrates under different environmental conditions, starting to unravel the role of subunit heterogeneity in this folding machine and establishing important links with the behavior of the most complex eukaryotic chaperonins.—Shoemark, D. K., Sessions, R. B., Brancaccio, A., Bigotti, M. G. Intraring allostery controls the function and assembly of a hetero-oligomeric class II chaperonin.
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Affiliation(s)
| | | | - Andrea Brancaccio
- School of Biochemistry, University of Bristol, Bristol, United Kingdom.,Istituto di Chimica del Riconoscimento Molecolare-Consiglio Nazionale delle Ricerche (CNR), Università Cattolica del Sacro Cuore, Rome, Italy
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25
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Roh SH, Hryc CF, Jeong HH, Fei X, Jakana J, Lorimer GH, Chiu W. Subunit conformational variation within individual GroEL oligomers resolved by Cryo-EM. Proc Natl Acad Sci U S A 2017; 114:8259-8264. [PMID: 28710336 PMCID: PMC5547627 DOI: 10.1073/pnas.1704725114] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Single-particle electron cryo-microscopy (cryo-EM) is an emerging tool for resolving structures of conformationally heterogeneous particles; however, each structure is derived from an average of many particles with presumed identical conformations. We used a 3.5-Å cryo-EM reconstruction with imposed D7 symmetry to further analyze structural heterogeneity among chemically identical subunits in each GroEL oligomer. Focused classification of the 14 subunits in each oligomer revealed three dominant classes of subunit conformations. Each class resembled a distinct GroEL crystal structure in the Protein Data Bank. The conformational differences stem from the orientations of the apical domain. We mapped each conformation class to its subunit locations within each GroEL oligomer in our dataset. The spatial distributions of each conformation class differed among oligomers, and most oligomers contained 10-12 subunits of the three dominant conformation classes. Adjacent subunits were found to more likely assume the same conformation class, suggesting correlation among subunits in the oligomer. This study demonstrates the utility of cryo-EM in revealing structure dynamics within a single protein oligomer.
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Affiliation(s)
- Soung-Hun Roh
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
| | - Corey F Hryc
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
- Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030
| | - Hyun-Hwan Jeong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030
| | - Xue Fei
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742
| | - Joanita Jakana
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
| | - George H Lorimer
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742
| | - Wah Chiu
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030;
- Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030
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26
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Koldewey P, Horowitz S, Bardwell JCA. Chaperone-client interactions: Non-specificity engenders multifunctionality. J Biol Chem 2017; 292:12010-12017. [PMID: 28620048 DOI: 10.1074/jbc.r117.796862] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Here, we provide an overview of the different mechanisms whereby three different chaperones, Spy, Hsp70, and Hsp60, interact with folding proteins, and we discuss how these chaperones may guide the folding process. Available evidence suggests that even a single chaperone can use many mechanisms to aid in protein folding, most likely due to the need for most chaperones to bind clients promiscuously. Chaperone mechanism may be better understood by always considering it in the context of the client's folding pathway and biological function.
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Affiliation(s)
- Philipp Koldewey
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Scott Horowitz
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - James C A Bardwell
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109; Howard Hughes Medical Institute, University of Michigan, Ann Arbor, Michigan 48109.
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27
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Sequential allosteric mechanism of ATP hydrolysis by the CCT/TRiC chaperone is revealed through Arrhenius analysis. Proc Natl Acad Sci U S A 2017; 114:5189-5194. [PMID: 28461478 DOI: 10.1073/pnas.1617746114] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Knowing the mechanism of allosteric switching is important for understanding how molecular machines work. The CCT/TRiC chaperonin nanomachine undergoes ATP-driven conformational changes that are crucial for its folding function. Here, we demonstrate that insight into its allosteric mechanism of ATP hydrolysis can be achieved by Arrhenius analysis. Our results show that ATP hydrolysis triggers sequential ‟conformational waves." They also suggest that these waves start from subunits CCT6 and CCT8 (or CCT3 and CCT6) and proceed clockwise and counterclockwise, respectively.
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28
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Song S, Chang J, Ma C, Tan YW. Single-Molecule Fluorescence Methods to Study Plant Hormone Signal Transduction Pathways. FRONTIERS IN PLANT SCIENCE 2017; 8:1888. [PMID: 29163610 PMCID: PMC5673658 DOI: 10.3389/fpls.2017.01888] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/18/2017] [Indexed: 05/15/2023]
Abstract
Plant-hormone-initiated signaling pathways are extremely vital for plant growth, differentiation, development, and adaptation to environmental stresses. Hormonal perception by receptors induces downstream signal transduction mechanisms that lead to plant responses. However, conventional techniques-such as genetics, biochemistry, and physiology methods-that are applied to elucidate these signaling pathways can only provide qualitative or ensemble-averaged quantitative results, and the intrinsic molecular mechanisms remain unclear. The present study developed novel methodologies based on in vitro single-molecule fluorescence assays to elucidate the complete and detailed mechanisms of plant hormone signal transduction pathways. The proposed methods are based on multicolor total internal reflection fluorescence microscopy and a flow cell model for gas environment control. The methods validate the effectiveness of single-molecule approaches for the extraction of abundant information, including oligomerization, specific gas dependence, and the interaction kinetics of different components.
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29
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Zang Y, Jin M, Wang H, Cui Z, Kong L, Liu C, Cong Y. Staggered ATP binding mechanism of eukaryotic chaperonin TRiC (CCT) revealed through high-resolution cryo-EM. Nat Struct Mol Biol 2016; 23:1083-1091. [PMID: 27775711 DOI: 10.1038/nsmb.3309] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 09/20/2016] [Indexed: 01/04/2023]
Abstract
The eukaryotic chaperonin TRiC (or CCT) assists in the folding of 10% of cytosolic proteins. Here we present two cryo-EM structures of Saccharomyces cerevisiae TRiC in a newly identified nucleotide partially preloaded (NPP) state and in the ATP-bound state, at 4.7-Å and 4.6-Å resolution, respectively. Through inner-subunit eGFP tagging, we identified the subunit locations in open-state TRiC and found that the CCT2 subunit pair forms an unexpected Z shape. ATP binding induces a dramatic conformational change on the CCT2 side, thereby suggesting that CCT2 plays an essential role in TRiC allosteric cooperativity. Our structural and biochemical data reveal a staggered ATP binding mechanism of TRiC with preloaded nucleotide on the CCT6 side of NPP-TRiC and demonstrate that TRiC has evolved into a complex that is structurally divided into two sides. This work offers insight into how the TRiC nucleotide cycle coordinates with its mechanical cycle in preparing folding intermediates for further productive folding.
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Affiliation(s)
- Yunxiang Zang
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Mingliang Jin
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Huping Wang
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhicheng Cui
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Liangliang Kong
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,Shanghai Science Research Center, Chinese Academy of Sciences, Shanghai, China
| | - Caixuan Liu
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yao Cong
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,Shanghai Science Research Center, Chinese Academy of Sciences, Shanghai, China
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30
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Tian H, Fürstenberg A, Huber T. Labeling and Single-Molecule Methods To Monitor G Protein-Coupled Receptor Dynamics. Chem Rev 2016; 117:186-245. [DOI: 10.1021/acs.chemrev.6b00084] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- He Tian
- Laboratory of Chemical Biology
and Signal Transduction, The Rockefeller University, 1230 York
Avenue, New York, New York 10065, United States
| | - Alexandre Fürstenberg
- Laboratory of Chemical Biology
and Signal Transduction, The Rockefeller University, 1230 York
Avenue, New York, New York 10065, United States
| | - Thomas Huber
- Laboratory of Chemical Biology
and Signal Transduction, The Rockefeller University, 1230 York
Avenue, New York, New York 10065, United States
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31
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Sydor AM, Czymmek KJ, Puchner EM, Mennella V. Super-Resolution Microscopy: From Single Molecules to Supramolecular Assemblies. Trends Cell Biol 2015; 25:730-748. [DOI: 10.1016/j.tcb.2015.10.004] [Citation(s) in RCA: 185] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 10/03/2015] [Accepted: 10/05/2015] [Indexed: 11/25/2022]
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32
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Abstract
As of 2015, it has been 26 years since the first optical detection and spectroscopy of single molecules in condensed matter. This area of science has expanded far beyond the early low temperature studies in crystals to include single molecules in cells, polymers, and in solution. The early steps relied upon high-resolution spectroscopy of inhomogeneously broadened optical absorption profiles of molecular impurities in solids at low temperatures. Spectral fine structure arising directly from the position-dependent fluctuations of the number of molecules in resonance led to the attainment of the single-molecule limit in 1989 using frequency-modulation laser spectroscopy. In the early 1990s, a variety of fascinating physical effects were observed for individual molecules, including imaging of the light from single molecules as well as observations of spectral diffusion, optical switching and the ability to select different single molecules in the same focal volume simply by tuning the pumping laser frequency. In the room temperature regime, researchers showed that bursts of light from single molecules could be detected in solution, leading to imaging and microscopy by a variety of methods. Studies of single copies of the green fluorescent protein also uncovered surprises, especially the blinking and photoinduced recovery of emitters, which stimulated further development of photoswitchable fluorescent protein labels. All of these early steps provided important fundamentals underpinning the development of super-resolution microscopy based on single-molecule localization and active control of emitting concentration. Current thrust areas include extensions to three-dimensional imaging with high precision, orientational analysis of single molecules, and direct measurements of photodynamics and transport properties for single molecules trapped in solution by suppression of Brownian motion. Without question, a huge variety of studies of single molecules performed by many talented scientists all over the world have extended our knowledge of the nanoscale and many microscopic mechanisms previously hidden by ensemble averaging.
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Affiliation(s)
- W E Moerner
- Department of Chemistry, Stanford University, Stanford, California 94305, USA.
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33
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Kumbhar S, Jana S, Anoop A, Waller MP. Cooperativity in bimetallic glutathione complexes. J Mol Graph Model 2015; 62:1-10. [DOI: 10.1016/j.jmgm.2015.05.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 04/30/2015] [Accepted: 05/05/2015] [Indexed: 01/03/2023]
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34
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Sharon M, Horovitz A. Probing allosteric mechanisms using native mass spectrometry. Curr Opin Struct Biol 2015; 34:7-16. [PMID: 26005781 DOI: 10.1016/j.sbi.2015.05.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 05/01/2015] [Accepted: 05/04/2015] [Indexed: 11/16/2022]
Abstract
Native mass spectrometry (MS) and ion mobility MS provide a way to discriminate between various allosteric mechanisms that cannot be distinguished using ensemble measurements of ligand binding in bulk protein solutions. Native MS, which yields mass measurements of intact assemblies, can be used to determine the values of ligand binding constants of multimeric allosteric proteins, thereby providing a way to distinguish, for example, between concerted and sequential allosteric models. Native MS can also be employed to study cooperativity owing to ligand-modulated protein oligomerization. The rotationally averaged cross-section areas of complexes obtained by ion mobility MS can be used to distinguish between induced fit and conformational selection. Native MS and its allied techniques are, therefore, becoming increasingly powerful tools for dissecting allosteric mechanisms.
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Affiliation(s)
- Michal Sharon
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Amnon Horovitz
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel.
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35
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The Mechanism and Function of Group II Chaperonins. J Mol Biol 2015; 427:2919-30. [PMID: 25936650 DOI: 10.1016/j.jmb.2015.04.013] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 04/22/2015] [Accepted: 04/23/2015] [Indexed: 12/19/2022]
Abstract
Protein folding in the cell requires the assistance of enzymes collectively called chaperones. Among these, the chaperonins are 1-MDa ring-shaped oligomeric complexes that bind unfolded polypeptides and promote their folding within an isolated chamber in an ATP-dependent manner. Group II chaperonins, found in archaea and eukaryotes, contain a built-in lid that opens and closes over the central chamber. In eukaryotes, the chaperonin TRiC/CCT is hetero-oligomeric, consisting of two stacked rings of eight paralogous subunits each. TRiC facilitates folding of approximately 10% of the eukaryotic proteome, including many cytoskeletal components and cell cycle regulators. Folding of many cellular substrates of TRiC cannot be assisted by any other chaperone. A complete structural and mechanistic understanding of this highly conserved and essential chaperonin remains elusive. However, recent work is beginning to shed light on key aspects of chaperonin function and how their unique properties underlie their contribution to maintaining cellular proteostasis.
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36
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Molecular mechanism of G-quadruplex unwinding helicase: sequential and repetitive unfolding of G-quadruplex by Pif1 helicase. Biochem J 2015; 466:189-99. [PMID: 25471447 DOI: 10.1042/bj20140997] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent advances in G-quadruplex (G4) studies have confirmed that G4 structures exist in living cells and may have detrimental effects on various DNA transactions. How helicases resolve G4, however, has just begun to be studied and remains largely unknown. In the present paper, we use single-molecule fluorescence assays to probe Pif1-catalysed unfolding of G4 in a DNA construct resembling an ongoing synthesis of lagging strand stalled by G4. Strikingly, Pif1 unfolds and then halts at the ss/dsDNA junction, followed by rapid reformation of G4 and 'acrobatic' re-initiation of unfolding by the same monomer. Thus, Pif1 unfolds single G4 structures repetitively. Furthermore, it is found that Pif1 unfolds G4 sequentially in two large steps. Our study has revealed that, as a stable intermediate, G-triplex (G3) plays an essential role in this process. The repetitive unfolding activity may facilitate Pif1 disrupting the continuously reforming obstructive G4 structures to rescue a stalled replication fork. The proposed mechanism for step-wise unfolding of G4 is probably applicable to other helicases that resolve G4 structures for maintaining genome stability.
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37
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Quantifying nucleoporin stoichiometry inside single nuclear pore complexes in vivo. Sci Rep 2015; 5:9372. [PMID: 25797490 PMCID: PMC4894440 DOI: 10.1038/srep09372] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 03/02/2015] [Indexed: 11/25/2022] Open
Abstract
The nuclear pore complex (NPC) is one of the largest supramolecular structures in eukaryotic cells. Its octagonal ring-scaffold perforates the nuclear envelope and features a unique molecular machinery that regulates nucleocytoplasmic transport. NPCs are composed of ~30 different nucleoporins (Nups), averaged at 8, 16 or 32 copies per NPC. This estimate has not been confirmed for individual NPCs in living cells due to the inherent difficulty of counting proteins inside single supramolecular complexes. Here we used single-molecule SPEED microscopy to directly count the copy-number of twenty-four different Nups within individual NPCs of live yeast, and found agreement as well as significant deviation from previous estimates. As expected, we counted 8 copies of four peripheral Nups and 16 copies of fourteen scaffold Nups. Unexpectedly, we counted a maximum of 16 copies of Nsp1 and Nic96, rather than 32 as previously estimated; and found only 10–15 copies of six other Nups, rather than 8 or 16 copies as expected. This in situ molecular-counting technology can test structure-function models of NPCs and other supramolecular structures in cells.
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38
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Fricke F, Dietz MS, Heilemann M. Single-Molecule Methods to Study Membrane Receptor Oligomerization. Chemphyschem 2014; 16:713-21. [DOI: 10.1002/cphc.201402765] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Indexed: 11/06/2022]
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39
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Bustamante CJ, Kaiser CM, Maillard RA, Goldman DH, Wilson CAM. Mechanisms of cellular proteostasis: insights from single-molecule approaches. Annu Rev Biophys 2014; 43:119-40. [PMID: 24895851 DOI: 10.1146/annurev-biophys-051013-022811] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cells employ a variety of strategies to maintain proteome homeostasis. Beginning during protein biogenesis, the translation machinery and a number of molecular chaperones promote correct de novo folding of nascent proteins even before synthesis is complete. Another set of molecular chaperones helps to maintain proteins in their functional, native state. Polypeptides that are no longer needed or pose a threat to the cell, such as misfolded proteins and aggregates, are removed in an efficient and timely fashion by ATP-dependent proteases. In this review, we describe how applications of single-molecule manipulation methods, in particular optical tweezers, are shedding new light on the molecular mechanisms of quality control during the life cycles of proteins.
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40
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Arant RJ, Ulbrich MH. Deciphering the subunit composition of multimeric proteins by counting photobleaching steps. Chemphyschem 2014; 15:600-5. [PMID: 24481650 DOI: 10.1002/cphc.201301092] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Indexed: 12/28/2022]
Abstract
The limit of subdiffraction imaging with fluorescent proteins currently lies at 20 nm, and therefore most protein complexes are too small (2-5 nm) to spatially resolve their individual subunits by optical means. However, the number and stoichiometry of subunits within an immobilized protein complex can be resolved by the observation of photobleaching steps of individual fluorophores or co-localization of single-molecule fluorescence emission in multiple colors. We give an overview of the proteins that have been investigated by this approach and the different techniques that can be used to immobilize and label the proteins. This minireview should serve as a guideline for scientists who want to employ single-molecule subunit counting for their research.
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Affiliation(s)
- Ryan J Arant
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720 (USA)
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41
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Zhang H, Guo P. Single molecule photobleaching (SMPB) technology for counting of RNA, DNA, protein and other molecules in nanoparticles and biological complexes by TIRF instrumentation. Methods 2014; 67:169-76. [PMID: 24440482 DOI: 10.1016/j.ymeth.2014.01.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 12/28/2013] [Accepted: 01/08/2014] [Indexed: 11/25/2022] Open
Abstract
Direct counting of biomolecules within biological complexes or nanomachines is demanding. Single molecule counting using optical microscopy is challenging due to the diffraction limit. The single molecule photobleaching (SMPB) technology for direct counting developed by our team (Shu et al., 2007 [18]; Zhang et al., 2007 [19]) offers a simple and straightforward method to determine the stoichiometry of molecules or subunits within biocomplexes or nanomachines at nanometer scales. Stoichiometry is determined by real-time observation of the number of descending steps resulted from the photobleaching of individual fluorophore. This technology has now been used extensively for single molecule counting of protein, RNA, and other macromolecules in a variety of complexes or nanostructures. Here, we elucidate the SMPB technology, using the counting of RNA molecules within a bacteriophage phi29 DNA-packaging biomotor as an example. The method described here can be applied to the single molecule counting of other molecules in other systems. The construction of a concise, simple and economical single molecule total internal reflection fluorescence (TIRF) microscope combining prism-type and objective-type TIRF is described. The imaging system contains a deep-cooled sensitive EMCCD camera with single fluorophore detection sensitivity, a laser combiner for simultaneous dual-color excitation, and a Dual-View™ imager to split the multiple outcome signals to different detector channels based on their wavelengths. Methodology of the single molecule photobleaching assay used to elucidate the stoichiometry of RNA on phi29 DNA packaging motor and the mechanism of protein/RNA interaction are described. Different methods for single fluorophore labeling of RNA molecules are reviewed. The process of statistical modeling to reveal the true copy number of the biomolecules based on binomial distribution is also described.
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Affiliation(s)
- Hui Zhang
- Nanobiotechnology Center, Markey Cancer Center, and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA.
| | - Peixuan Guo
- Nanobiotechnology Center, Markey Cancer Center, and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA.
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42
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Grima R. Anomalous fluctuation scaling laws in stochastic enzyme kinetics: increase of noise strength with the mean concentration. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:012710. [PMID: 24580260 DOI: 10.1103/physreve.89.012710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Indexed: 06/03/2023]
Abstract
It is commonly thought that if a rate constant is perturbed such that the intracellular concentration of a certain species increases, then the fluctuations in the concentration will correspondingly decrease in strength. We here test whether this conventional wisdom generally holds true. We study the dependence of the noise strength (the coefficient of variation) in protein concentrations as a function of the mean protein concentration for a system in which protein is transported in and out of an intracellular compartment and it is catalyzed into a product by a multisubunit enzyme inside the compartment. The mean protein concentration is varied through perturbation of one of the rate constants. For low protein concentrations, the noise strength scales as [P]-1/2, where [P] is the mean concentration; this is the conventional fluctuation scaling law. However, we show that over a wide range of physiological concentrations, there are manifest anomalous fluctuation scaling laws proportional to [P]0 and [P](N-1)/2, where N is the number of binding sites of the multisubunit enzyme. These laws are particularly conspicuous when the rate of protein import into the compartment is much larger than its export rate out of the compartment and when the enzyme exhibits positive cooperativity. The results imply that over a certain range of physiological concentrations, noise strength remains the same or increases with the mean protein concentration. This contradicts the popularly held notion that noise strength decreases with increasing concentration and suggests that noise can be important even when the number of molecules is large.
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Affiliation(s)
- Ramon Grima
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
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43
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Hoersch D, Roh SH, Chiu W, Kortemme T. Reprogramming an ATP-driven protein machine into a light-gated nanocage. NATURE NANOTECHNOLOGY 2013; 8:928-32. [PMID: 24270642 PMCID: PMC3859876 DOI: 10.1038/nnano.2013.242] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Accepted: 10/16/2013] [Indexed: 05/06/2023]
Abstract
Natural protein assemblies have many sophisticated architectures and functions, creating nanoscale storage containers, motors and pumps. Inspired by these systems, protein monomers have been engineered to self-assemble into supramolecular architectures including symmetrical, metal-templated and cage-like structures. The complexity of protein machines, however, has made it difficult to create assemblies with both defined structures and controllable functions. Here we report protein assemblies that have been engineered to function as light-controlled nanocontainers. We show that an adenosine-5'-triphosphate-driven group II chaperonin, which resembles a barrel with a built-in lid, can be reprogrammed to open and close on illumination with different wavelengths of light. By engineering photoswitchable azobenzene-based molecules into the structure, light-triggered changes in interatomic distances in the azobenzene moiety are able to drive large-scale conformational changes of the protein assembly. The different states of the assembly can be visualized with single-particle cryo-electron microscopy, and the nanocages can be used to capture and release non-native cargos. Similar strategies that switch atomic distances with light could be used to build other controllable nanoscale machines.
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Affiliation(s)
- Daniel Hoersch
- Department of Bioengineering and Therapeutic Sciences and California Institute for Quantitative Biomedical Research, University of California, San Francisco, San Francisco, CA 94158
| | - Soung-Hun Roh
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Wah Chiu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Tanja Kortemme
- Department of Bioengineering and Therapeutic Sciences and California Institute for Quantitative Biomedical Research, University of California, San Francisco, San Francisco, CA 94158
- Correspondence to: Tanja Kortemme, University of California, San Francisco, 1700 4 Street, Byers Hall 308E, San Francisco, CA 94158, Phone: (415)514-1368, Fax: (415)514-4797,
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44
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Mashaghi A, Kramer G, Lamb DC, Mayer MP, Tans SJ. Chaperone Action at the Single-Molecule Level. Chem Rev 2013; 114:660-76. [DOI: 10.1021/cr400326k] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Alireza Mashaghi
- AMOLF Institute, Science Park
104, 1098 XG Amsterdam, The Netherlands
| | - Günter Kramer
- Zentrum
für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Don C. Lamb
- Physical
Chemistry, Department of Chemistry, Munich Center for Integrated Protein
Science (CiPSM) and Center for Nanoscience, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Gerhard-Ertl-Building, 81377 Munich, Germany
| | - Matthias P. Mayer
- Zentrum
für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Sander J. Tans
- AMOLF Institute, Science Park
104, 1098 XG Amsterdam, The Netherlands
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45
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Zhao Y, Chen D, Yue H, French JB, Rufo J, Benkovic SJ, Huang TJ. Lab-on-a-chip technologies for single-molecule studies. LAB ON A CHIP 2013; 13:2183-98. [PMID: 23670195 PMCID: PMC3955889 DOI: 10.1039/c3lc90042h] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Recent developments on various lab-on-a-chip techniques allow miniaturized and integrated devices to perform on-chip single-molecule studies. Fluidic-based platforms that utilize unique microscale fluidic behavior are capable of conducting single-molecule experiments with high sensitivities and throughputs, while biomolecular systems can be studied on-chip using techniques such as DNA curtains, magnetic tweezers, and solid-state nanopores. The advances of these on-chip single-molecule techniques lead to next-generation lab-on-a-chip devices, such as DNA transistors, and single-molecule real-time (SMRT) technology for rapid and low-cost whole genome DNA sequencing. In this Focus article, we will discuss some recent successes in the development of lab-on-a-chip techniques for single-molecule studies and expound our thoughts on the near future of on-chip single-molecule studies.
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Affiliation(s)
- Yanhui Zhao
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802 USA
| | - Danqi Chen
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 USA
| | - Hongjun Yue
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 USA
| | - Jarrod B. French
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 USA
| | - Joey Rufo
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802 USA
| | - Stephen J. Benkovic
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 USA
| | - Tony Jun Huang
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802 USA
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46
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Sprödefeld A, Kiel A, Herten DP, Krämer R. Monitoring Cu2+-Binding to a DNA-Clip-phen Conjugate and Metal-centered Redox Processes by a Fluorescent Reporter Group. Z Anorg Allg Chem 2013. [DOI: 10.1002/zaac.201300077] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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47
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Rybina A, Lang C, Wirtz M, Grußmayer K, Kurz A, Maier F, Schmitt A, Trapp O, Jung G, Herten DP. Direkte Beobachtung alternativer Reaktionswege an einzelnen Molekülen. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201300100] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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48
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Rybina A, Lang C, Wirtz M, Grußmayer K, Kurz A, Maier F, Schmitt A, Trapp O, Jung G, Herten DP. Distinguishing Alternative Reaction Pathways by Single-Molecule Fluorescence Spectroscopy. Angew Chem Int Ed Engl 2013; 52:6322-5. [DOI: 10.1002/anie.201300100] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Revised: 02/25/2013] [Indexed: 11/07/2022]
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49
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Kalisman N, Schröder GF, Levitt M. The crystal structures of the eukaryotic chaperonin CCT reveal its functional partitioning. Structure 2013; 21:540-9. [PMID: 23478063 DOI: 10.1016/j.str.2013.01.017] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/20/2013] [Accepted: 01/28/2013] [Indexed: 12/22/2022]
Abstract
In eukaryotes, CCT is essential for the correct and efficient folding of many cytosolic proteins, most notably actin and tubulin. Structural studies of CCT have been hindered by the failure of standard crystallographic analysis to resolve its eight different subunit types at low resolutions. Here, we exhaustively assess the R value fit of all possible CCT models to available crystallographic data of the closed and open forms with resolutions of 3.8 Å and 5.5 Å, respectively. This unbiased analysis finds the native subunit arrangements with overwhelming significance. The resulting structures provide independent crystallographic proof of the subunit arrangement of CCT and map major asymmetrical features of the particle onto specific subunits. The actin and tubulin substrates both bind around subunit CCT6, which shows other structural anomalies. CCT is thus clearly partitioned, both functionally and evolutionary, into a substrate-binding side that is opposite to the ATP-hydrolyzing side.
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Affiliation(s)
- Nir Kalisman
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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50
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Yin Y, Yuan R, Zhao XS. Amplitude of Relaxations in Fluorescence Correlation Spectroscopy for Fluorophores That Diffuse Together. J Phys Chem Lett 2013; 4:304-309. [PMID: 26283439 DOI: 10.1021/jz301871f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The amplitude of chemical relaxations in fluorescence correlation spectroscopy (FCS) is an important parameter that directly relates to not only the equilibrium constant of the relaxations but also the number of individual fluorophores that diffuse together. In this Letter we answer the question how exactly the amplitude of the relaxations in FCS changes with respect to the number of identical fluorophores on one cargo. We anchored tetramethylrhodamine molecules onto each arm of a DNA Holliday junction molecule so that the codiffusing dyes were capable of performing independent fluorescent fluctuations. We found that the amplitudes of the relaxations were inversely proportional to the number of the dyes on each cargo molecule, well agreeing with the theoretical prediction derived in this Letter. The result provides a guideline for the FCS data analysis and points out a simple way to determine the number of molecules that a cargo carries.
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Affiliation(s)
- Yandong Yin
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Department of Chemical Biology, College of Chemistry and Molecular Engineering, and Biodynamic Optical Imaging Center (BIOPIC), Peking University, Beijing, 100871, China
| | - Rongfeng Yuan
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Department of Chemical Biology, College of Chemistry and Molecular Engineering, and Biodynamic Optical Imaging Center (BIOPIC), Peking University, Beijing, 100871, China
| | - Xin Sheng Zhao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Department of Chemical Biology, College of Chemistry and Molecular Engineering, and Biodynamic Optical Imaging Center (BIOPIC), Peking University, Beijing, 100871, China
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