1
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Saha R, Choi JA, Chen IA. Protocell Effects on RNA Folding, Function, and Evolution. Acc Chem Res 2024; 57:2058-2066. [PMID: 39005057 PMCID: PMC11308369 DOI: 10.1021/acs.accounts.4c00174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 06/03/2024] [Accepted: 07/03/2024] [Indexed: 07/16/2024]
Abstract
ConspectusCreating a living system from nonliving matter is a great challenge in chemistry and biophysics. The early history of life can provide inspiration from the idea of the prebiotic "RNA World" established by ribozymes, in which all genetic and catalytic activities were executed by RNA. Such a system could be much simpler than the interdependent central dogma characterizing life today. At the same time, cooperative systems require a mechanism such as cellular compartmentalization in order to survive and evolve. Minimal cells might therefore consist of simple vesicles enclosing a prebiotic RNA metabolism.The internal volume of a vesicle is a distinctive environment due to its closed boundary, which alters diffusion and available volume for macromolecules and changes effective molecular concentrations, among other considerations. These physical effects are mechanistically distinct from chemical interactions, such as electrostatic repulsion, that might also occur between the membrane boundary and encapsulated contents. Both indirect and direct interactions between the membrane and RNA can give rise to nonintuitive, "emergent" behaviors in the model protocell system. We have been examining how encapsulation inside membrane vesicles would affect the folding and activity of entrapped RNA.Using biophysical techniques such as FRET, we characterized ribozyme folding and activity inside vesicles. Encapsulation inside model protocells generally promoted RNA folding, consistent with an excluded volume effect, independently of chemical interactions. This energetic stabilization translated into increased ribozyme activity in two different systems that were studied (hairpin ribozyme and self-aminoacylating RNAs). A particularly intriguing finding was that encapsulation could rescue the activity of mutant ribozymes, suggesting that encapsulation could affect not only folding and activity but also evolution. To study this further, we developed a high-throughput sequencing assay to measure the aminoacylation kinetics of many thousands of ribozyme variants in parallel. The results revealed an unexpected tendency for encapsulation to improve the better ribozyme variants more than worse variants. During evolution, this effect would create a tilted playing field, so to speak, that would give additional fitness gains to already-high-activity variants. According to Fisher's Fundamental Theorem of Natural Selection, the increased variance in fitness should manifest as faster evolutionary adaptation. This prediction was borne out experimentally during in vitro evolution, where we observed that the initially diverse ribozyme population converged more quickly to the most active sequences when they were encapsulated inside vesicles.The studies in this Account have expanded our understanding of emergent protocell behavior, by showing how simply entrapping an RNA inside a vesicle, which could occur spontaneously during vesicle formation, might profoundly affect the evolutionary landscape of the RNA. Because of the exponential dynamics of replication and selection, even small changes to activity and function could lead to major evolutionary consequences. By closely studying the details of minimal yet surprisingly complex protocells, we might one day trace a pathway from encapsulated RNA to a living system.
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Affiliation(s)
- Ranajay Saha
- Department of Chemical and Biomolecular
Engineering, Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095-1592, United States
| | - Jongseok A. Choi
- Department of Chemical and Biomolecular
Engineering, Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095-1592, United States
| | - Irene A. Chen
- Department of Chemical and Biomolecular
Engineering, Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095-1592, United States
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2
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Dore MD, Rafique MG, Yang TP, Zorman M, Platnich CM, Xu P, Trinh T, Rizzuto FJ, Cosa G, Li J, Guarné A, Sleiman HF. Heat-activated growth of metastable and length-defined DNA fibers expands traditional polymer assembly. Nat Commun 2024; 15:4384. [PMID: 38782917 PMCID: PMC11116425 DOI: 10.1038/s41467-024-48722-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 05/13/2024] [Indexed: 05/25/2024] Open
Abstract
Biopolymers such as nucleic acids and proteins exhibit dynamic backbone folding, wherein site-specific intramolecular interactions determine overall structure. Proteins then hierarchically assemble into supramolecular polymers such as microtubules, that are robust yet dynamic, constantly growing or shortening to adjust to cellular needs. The combination of dynamic, energy-driven folding and growth with structural stiffness and length control is difficult to achieve in synthetic polymer self-assembly. Here we show that highly charged, monodisperse DNA-oligomers assemble via seeded growth into length-controlled supramolecular fibers during heating; when the temperature is lowered, these metastable fibers slowly disassemble. Furthermore, the specific molecular structures of oligomers that promote fiber formation contradict the typical theory of block copolymer self-assembly. Efficient curling and packing of the oligomers - or 'curlamers' - determine morphology, rather than hydrophobic to hydrophilic ratio. Addition of a small molecule stabilises the DNA fibers, enabling temporal control of polymer lifetime and underscoring their potential use in nucleic-acid delivery, stimuli-responsive biomaterials, and soft robotics.
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Affiliation(s)
- Michael D Dore
- Department of Chemistry, McGill University, 801 Sherbrooke St W, Montréal, QC, H3A 08B, Canada
| | | | - Tianxiao Peter Yang
- Department of Biochemistry and Centre de Recherche en Biologie Structurale, McGill University, Montréal, QC, Canada
| | - Marlo Zorman
- Department of Chemistry, University of Vermont, Burlington, VT, 05405, USA
| | - Casey M Platnich
- Department of Chemistry, McGill University, 801 Sherbrooke St W, Montréal, QC, H3A 08B, Canada
| | - Pengfei Xu
- Department of Chemistry, McGill University, 801 Sherbrooke St W, Montréal, QC, H3A 08B, Canada
| | - Tuan Trinh
- Department of Chemistry, McGill University, 801 Sherbrooke St W, Montréal, QC, H3A 08B, Canada
| | - Felix J Rizzuto
- School of Chemistry, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Gonzalo Cosa
- Department of Chemistry, McGill University, 801 Sherbrooke St W, Montréal, QC, H3A 08B, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montréal, QC, Canada
| | - Jianing Li
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, 47906, USA
| | - Alba Guarné
- Department of Biochemistry and Centre de Recherche en Biologie Structurale, McGill University, Montréal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montréal, QC, Canada
| | - Hanadi F Sleiman
- Department of Chemistry, McGill University, 801 Sherbrooke St W, Montréal, QC, H3A 08B, Canada.
- Centre de Recherche en Biologie Structurale, McGill University, Montréal, QC, Canada.
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3
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Kundu P, Saha S, Gangopadhyay G. A minimal kinetic model for the interpretation of complex catalysis in single enzyme molecules. Phys Chem Chem Phys 2023; 26:463-476. [PMID: 38078459 DOI: 10.1039/d3cp01720f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Multi-exponential waiting-time distribution and randomness parameter greater than unity ascribe dynamic disorder in single-enzyme catalysis corroborated to the interplay of transforming conformers [English et al., Nat. Chem. Biol., 2006, 2, 87]. The associated multi-state model of enzymatic turnovers with statically heterogeneous catalytic rates misdescribes the non-linear uprising of the randomness parameter from unity in relation to the attributes of the fall-offs of the waiting-time distribution at different substrate concentrations. To resolve this crucial issue, we first employ a comprehensive stochastic reaction scenario and further rationalize and work out the minimal indispensable dynamic-disorder model that ensures the foregoing relationship upon comparison with the data. We elucidate that specific disregard for the transition rate coefficients in the multi-state model on account of the especially slow conformational transitions is the underlying reason for not achieving interrelation between the observables.
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Affiliation(s)
- Prasanta Kundu
- S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India
| | - Soma Saha
- Department of Chemistry, Presidency University, 86/1 College Street, Kolkata 700073, India.
| | - Gautam Gangopadhyay
- S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India
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4
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Gulzar A, Noetzel J, Forbert H, Marx D. Elucidating the Self-cleavage Dynamics of Hairpin Ribozyme by Mode-decomposed Infrared Spectroscopy. J Phys Chem Lett 2023; 14:7940-7945. [PMID: 37646493 DOI: 10.1021/acs.jpclett.3c01724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
While catalytic reactions of biomolecular processes play an indispensable role in life, extracting the underlying molecular picture often remains challenging. Based on ab initio simulations of the self-cleavage reaction of hairpin ribozyme, mode-decomposed infrared spectra, and cosine similarity analysis to correlate the product with reactant IR spectra, we demonstrate a strategy to extract molecular details from characteristic spectral changes. Our results are in almost quantitative agreement with the experimental IR band library of nucleic acids and suggest that the spectral range of 800-1200 cm-1 is particularly valuable to monitor self-cleavage. Importantly, the cosine similarities also disclose that IR peaks subject to slight shifts due to self-cleavage might be unrelated, while strongly shifting resonances can correspond to the same structural dynamics. This framework of correlating complex IR spectra at the molecular level along biocatalytic reaction pathways is broadly applicable.
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Affiliation(s)
- Adnan Gulzar
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Jan Noetzel
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Harald Forbert
- Center for Solvation Science ZEMOS, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
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5
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Suddala KC, Yoo J, Fan L, Zuo X, Wang YX, Chung HS, Zhang J. Direct observation of tRNA-chaperoned folding of a dynamic mRNA ensemble. Nat Commun 2023; 14:5438. [PMID: 37673863 PMCID: PMC10482949 DOI: 10.1038/s41467-023-41155-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 08/24/2023] [Indexed: 09/08/2023] Open
Abstract
T-box riboswitches are multi-domain noncoding RNAs that surveil individual amino acid availabilities in most Gram-positive bacteria. T-boxes directly bind specific tRNAs, query their aminoacylation status to detect starvation, and feedback control the transcription or translation of downstream amino-acid metabolic genes. Most T-boxes rapidly recruit their cognate tRNA ligands through an intricate three-way stem I-stem II-tRNA interaction, whose establishment is not understood. Using single-molecule FRET, SAXS, and time-resolved fluorescence, we find that the free T-box RNA assumes a broad distribution of open, semi-open, and closed conformations that only slowly interconvert. tRNA directly binds all three conformers with distinct kinetics, triggers nearly instantaneous collapses of the open conformations, and returns the T-box RNA to their pre-binding conformations upon dissociation. This scissors-like dynamic behavior is enabled by a hinge-like pseudoknot domain which poises the T-box for rapid tRNA-induced domain closure. This study reveals tRNA-chaperoned folding of flexible, multi-domain mRNAs through a Venus flytrap-like mechanism.
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Affiliation(s)
- Krishna C Suddala
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA
| | - Janghyun Yoo
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA
| | - Lixin Fan
- Basic Science Program, Frederick National Laboratory for Cancer Research, Small-Angle X-Ray Scattering Core Facility of National Cancer Institute, Frederick, MD, 21702, USA
| | - Xiaobing Zuo
- X-ray Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Yun-Xing Wang
- Basic Science Program, Frederick National Laboratory for Cancer Research, Small-Angle X-Ray Scattering Core Facility of National Cancer Institute, Frederick, MD, 21702, USA
- Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Hoi Sung Chung
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA.
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA.
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6
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Ghoneim M, Musselman CA. Single-Molecule Characterization of Cy3.5 -Cy5.5 Dye Pair for FRET Studies of Nucleic Acids and Nucleosomes. J Fluoresc 2023; 33:413-421. [PMID: 36435903 PMCID: PMC9957830 DOI: 10.1007/s10895-022-03093-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 11/17/2022] [Indexed: 11/27/2022]
Abstract
Single molecule FRET (Forster resonance energy transfer) is very powerful method for studying biomolecular binding dynamics and conformational transitions. Only a few donor - acceptor dye pairs have been characterized for use in single-molecule FRET (smFRET) studies. Hence, introducing and characterizing additional FRET dye pairs is important in order to widen the scope of applications of single-molecule FRET in biomolecular studies. Here we characterize the properties of the Cy3.5 and Cy5.5 dye pair under FRET at the single-molecule level using naked double-stranded DNA (dsDNA) and the nucleosome. We show that this pair of dyes is photostable for ~ 5 min under continuous illumination. We also report Cy3.5-Cy5.5 FRET proximity dependence and stability in the presence of several biochemical buffers and photoprotective reagents in the context of double-stranded DNA. Finally, we demonstrate compatibility of the Cy3.5-Cy5.5 pair for smFRET in vitro studies of nucleosomes.
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Affiliation(s)
- Mohamed Ghoneim
- Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, 80045, Aurora, CO, USA.
| | - Catherine A. Musselman
- grid.430503.10000 0001 0703 675XBiochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, 80045 Aurora, CO USA
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7
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Singh D, Punia B, Chaudhury S. Theoretical Tools to Quantify Stochastic Fluctuations in Single-Molecule Catalysis by Enzymes and Nanoparticles. ACS OMEGA 2022; 7:47587-47600. [PMID: 36591158 PMCID: PMC9798497 DOI: 10.1021/acsomega.2c06316] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 12/02/2022] [Indexed: 06/11/2023]
Abstract
Single-molecule microscopic techniques allow the counting of successive turnover events and the study of the time-dependent fluctuations of the catalytic activities of individual enzymes and different sites on a single heterogeneous nanocatalyst. It is important to establish theoretical methods to obtain the statistical measurements of such stochastic fluctuations that provide insight into the catalytic mechanism. In this review, we discuss a few theoretical frameworks for evaluating the first passage time distribution functions using a self-consistent pathway approach and chemical master equations, to establish a connection with experimental observables. The measurable probability distribution functions and their moments depend on the molecular details of the reaction and provide a way to quantify the molecular mechanisms of the reaction process. The statistical measurements of these fluctuations should provide insight into the enzymatic mechanism.
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Affiliation(s)
- Divya Singh
- School
of Chemistry, Tel Aviv University, Tel Aviv6997801, Israel
| | - Bhawakshi Punia
- Department
of Chemistry, Indian Institute of Science
Education and Research, Dr. Homi Bhabha Road, Pune411008, Maharashtra, India
| | - Srabanti Chaudhury
- Department
of Chemistry, Indian Institute of Science
Education and Research, Dr. Homi Bhabha Road, Pune411008, Maharashtra, India
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8
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Vermeer B, Schmid S. Can DyeCycling break the photobleaching limit in single-molecule FRET? NANO RESEARCH 2022; 15:9818-9830. [PMID: 35582137 PMCID: PMC9101981 DOI: 10.1007/s12274-022-4420-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 05/03/2023]
Abstract
Biomolecular systems, such as proteins, crucially rely on dynamic processes at the nanoscale. Detecting biomolecular nanodynamics is therefore key to obtaining a mechanistic understanding of the energies and molecular driving forces that control biomolecular systems. Single-molecule fluorescence resonance energy transfer (smFRET) is a powerful technique to observe in real-time how a single biomolecule proceeds through its functional cycle involving a sequence of distinct structural states. Currently, this technique is fundamentally limited by irreversible photobleaching, causing the untimely end of the experiment and thus, a narrow temporal bandwidth of ≤ 3 orders of magnitude. Here, we introduce "DyeCycling", a measurement scheme with which we aim to break the photobleaching limit in smFRET. We introduce the concept of spontaneous dye replacement by simulations, and as an experimental proof-of-concept, we demonstrate the intermittent observation of a single biomolecule for one hour with a time resolution of milliseconds. Theoretically, DyeCycling can provide > 100-fold more information per single molecule than conventional smFRET. We discuss the experimental implementation of DyeCycling, its current and fundamental limitations, and specific biological use cases. Given its general simplicity and versatility, DyeCycling has the potential to revolutionize the field of time-resolved smFRET, where it may serve to unravel a wealth of biomolecular dynamics by bridging from milliseconds to the hour range. Electronic Supplementary Material Supplementary material is available for this article at 10.1007/s12274-022-4420-5 and is accessible for authorized users.
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Affiliation(s)
- Benjamin Vermeer
- NanoDynamicsLab, Laboratory of Biophysics, Wageningen University, Stippeneng 4, 6708WE Wageningen, The Netherlands
| | - Sonja Schmid
- NanoDynamicsLab, Laboratory of Biophysics, Wageningen University, Stippeneng 4, 6708WE Wageningen, The Netherlands
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9
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Peng H, Lelievre A, Landenfeld K, Müller S, Chen IA. Vesicle encapsulation stabilizes intermolecular association and structure formation of functional RNA and DNA. Curr Biol 2022; 32:86-96.e6. [PMID: 34762821 PMCID: PMC8752491 DOI: 10.1016/j.cub.2021.10.047] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/02/2021] [Accepted: 10/21/2021] [Indexed: 01/12/2023]
Abstract
During the origin of life, encapsulation of RNA inside vesicles is believed to have been a defining feature of the earliest cells (protocells). The confined biophysical environment provided by membrane encapsulation differs from that of bulk solution and has been shown to increase activity as well as evolutionary rate for functional RNA. However, the structural basis of the effect on RNA has not been clear. Here, we studied how encapsulation of the hairpin ribozyme inside model protocells affects ribozyme kinetics, ribozyme folding into the active conformation, and cleavage and ligation activities. We further examined the effect of encapsulation on the folding of a stem-loop RNA structure and on the formation of a triplex structure in a pH-sensitive DNA switch. The results indicate that encapsulation promotes RNA-RNA association, both intermolecular and intramolecular, and also stabilizes tertiary folding, including the docked conformation characteristic of the active hairpin ribozyme and the triplex structure. The effects of encapsulation were sufficient to rescue the activity of folding-deficient mutants of the hairpin ribozyme. Stabilization of multiple modes of nucleic acid folding and interaction thus enhanced the activity of encapsulated nucleic acids. Increased association between RNA molecules may facilitate the formation of more complex structures and cooperative interactions. These effects could promote the emergence of biological functions in an "RNA world" and may have utility in the construction of minimal synthetic cells.
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Affiliation(s)
- Huan Peng
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA
| | - Amandine Lelievre
- Institute of Biochemistry, University of Greifswald, 17487 Greifswald, Germany
| | | | - Sabine Müller
- Institute of Biochemistry, University of Greifswald, 17487 Greifswald, Germany
| | - Irene A. Chen
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA,Lead Contact:
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10
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Ciftci D, Martens C, Ghani VG, Blanchard SC, Politis A, Huysmans GHM, Boudker O. Linking function to global and local dynamics in an elevator-type transporter. Proc Natl Acad Sci U S A 2021; 118:e2025520118. [PMID: 34873050 PMCID: PMC8670510 DOI: 10.1073/pnas.2025520118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2021] [Indexed: 11/24/2022] Open
Abstract
Transporters cycle through large structural changes to translocate molecules across biological membranes. The temporal relationships between these changes and function, and the molecular properties setting their rates, determine transport efficiency-yet remain mostly unknown. Using single-molecule fluorescence microscopy, we compare the timing of conformational transitions and substrate uptake in the elevator-type transporter GltPh We show that the elevator-like movements of the substrate-loaded transport domain across membranes and substrate release are kinetically heterogeneous, with rates varying by orders of magnitude between individual molecules. Mutations increasing the frequency of elevator transitions and reducing substrate affinity diminish transport rate heterogeneities and boost transport efficiency. Hydrogen deuterium exchange coupled to mass spectrometry reveals destabilization of secondary structure around the substrate-binding site, suggesting that increased local dynamics leads to faster rates of global conformational changes and confers gain-of-function properties that set transport rates.
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Affiliation(s)
- Didar Ciftci
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065
- Tri-Institutional Training Program in Chemical Biology, New York, NY 10065
| | - Chloe Martens
- Department of Chemistry, King's College London, London SE1 1DB, United Kingdom
| | - Vishnu G Ghani
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065
| | - Scott C Blanchard
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Argyris Politis
- Department of Chemistry, King's College London, London SE1 1DB, United Kingdom
| | - Gerard H M Huysmans
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065;
| | - Olga Boudker
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065;
- Tri-Institutional Training Program in Chemical Biology, New York, NY 10065
- Howard Hughes Medical Institute, Weill Cornell Medicine, New York, NY 10065
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11
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Largy E, König A, Ghosh A, Ghosh D, Benabou S, Rosu F, Gabelica V. Mass Spectrometry of Nucleic Acid Noncovalent Complexes. Chem Rev 2021; 122:7720-7839. [PMID: 34587741 DOI: 10.1021/acs.chemrev.1c00386] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nucleic acids have been among the first targets for antitumor drugs and antibiotics. With the unveiling of new biological roles in regulation of gene expression, specific DNA and RNA structures have become very attractive targets, especially when the corresponding proteins are undruggable. Biophysical assays to assess target structure as well as ligand binding stoichiometry, affinity, specificity, and binding modes are part of the drug development process. Mass spectrometry offers unique advantages as a biophysical method owing to its ability to distinguish each stoichiometry present in a mixture. In addition, advanced mass spectrometry approaches (reactive probing, fragmentation techniques, ion mobility spectrometry, ion spectroscopy) provide more detailed information on the complexes. Here, we review the fundamentals of mass spectrometry and all its particularities when studying noncovalent nucleic acid structures, and then review what has been learned thanks to mass spectrometry on nucleic acid structures, self-assemblies (e.g., duplexes or G-quadruplexes), and their complexes with ligands.
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Affiliation(s)
- Eric Largy
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Alexander König
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Anirban Ghosh
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Debasmita Ghosh
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Sanae Benabou
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Frédéric Rosu
- Univ. Bordeaux, CNRS, INSERM, IECB, UMS 3033, F-33600 Pessac, France
| | - Valérie Gabelica
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
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12
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Kundu P, Saha S, Gangopadhyay G. A Revisit to Turnover Kinetics of Individual Escherichia coli β-Galactosidase Molecules. J Phys Chem B 2021; 125:8010-8020. [PMID: 34270240 DOI: 10.1021/acs.jpcb.1c04299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Single-molecule experiments on β-galactosidase from Escherichia coli that catalyzes the hydrolysis of resorufin-β-d-galactopyranoside revealed important observations like fluctuating catalytic rate, memory effects arising from temporal correlations between the enzymatic turnovers and nonexponential waiting time distributions. The root cause of the observed results is intrinsic fluctuations among the different conformers of the active species, during the course of the reaction, thereby imparting dynamic disorder in the system under investigation. Originally, a multistate stochastic kinetic theory was employed that, despite satisfying the measured waiting time distributions and the mean waiting times at different substrate concentrations, yields a constant estimate of the randomness parameter. Inevitably, this manifests a strong disagreement with the substrate-concentration-dependent time variations of the said distribution, which at the same time misinterprets the measured magnitudes of the randomness parameter at lower concentrations. Here, we suggest a dual approach to the single-enzyme reaction, independently, making important improvements over the parent study and the recently suggested two-state stochastic analyses followed by quantitative rationalization of the experimental data. In the first case, an off-pathway mechanism satisfied the Michaelis-Menten equation under the circumstance of prevailing disorder while tested against the single-molecule data. However, recovery of randomness data in the lower-concentration regime, albeit primarily marks a significant refinement, a qualitative agreement at the growing concentrations seems to be reasoned by an account of switching among the limited numbers of discrete conformers. Consequently, in the second case, we circumvented the conventional way of approaching the enzyme catalysis and mapped the dynamics of structural transitions of the biocatalyst with the temporal fluctuations of the spatial distance between the different locations along a coarse-grained polymer chain. Exploiting a general mechanism for dynamic disorder, a reaction-diffusion formalism yielded an analytical expression for the waiting time distribution of the enzymatic turnovers, from which the mean waiting time and the randomness parameter were readily determined. Application of our results to the findings of the experiment on single β-galactosidase shows a quantitative agreement in each case. This soundly validates the usefulness of accounting for a more rigorous microscopic description pertinent to the conformational multiplicity in rationalizing the real-time data over the routine state-based sketch of the reaction system.
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Affiliation(s)
- Prasanta Kundu
- S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India
| | - Soma Saha
- Department of Chemistry, Presidency University, 86/1 College Street, Kolkata 700073, India
| | - Gautam Gangopadhyay
- S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India
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13
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Wilson H, Wang Q. ABEL-FRET: tether-free single-molecule FRET with hydrodynamic profiling. Nat Methods 2021; 18:816-820. [PMID: 34127856 DOI: 10.1038/s41592-021-01173-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 05/04/2021] [Indexed: 02/03/2023]
Abstract
Single-molecule Förster resonance energy transfer (smFRET) has become a versatile and widespread method to probe nanoscale conformation and dynamics. However, current experimental modalities often resort to molecule immobilization for long observation times and do not always approach the resolution limit of FRET-based nanoscale metrology. Here we present ABEL-FRET, an immobilization-free platform for smFRET measurements with ultrahigh resolving power in FRET efficiency. Importantly, single-molecule diffusivity is used to provide additional size and shape information for hydrodynamic profiling of individual molecules, which, together with the concurrently measured intramolecular conformation through FRET, enables a holistic and dynamic view of biomolecules and their complexes.
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Affiliation(s)
- Hugh Wilson
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Quan Wang
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.
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14
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Wang L, Zhang J, Han M, Zhang L, Chen C, Huang A, Xie R, Wang G, Zhu J, Wang Y, Liu X, Zhuang W, Li Y, Wang J. A Genetically Encoded Two‐Dimensional Infrared Probe for Enzyme Active‐Site Dynamics. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Li Wang
- School of Life Sciences University of Chinese Academy of Sciences Yuquan Road, Shijingshan District Beijing 100049 China
- Institute of Biophysics Chinese Academy of Sciences Datun Road, Chaoyang District Beijing 100101 China
| | - Jia Zhang
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China
- School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049 China
| | - Ming‐Jie Han
- Tianjin Institute of Industrial Biotechnology Chinese Academy of Sciences West 7th Avenue, Tianjin Airport Economic Area Tianjin 300308 China
- Shenzhen Institute of Transfusion Medicine Shenzhen Blood Center Futian District Shenzhen 518052 China
| | - Lu Zhang
- State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences Fuzhou 350002 China
| | - Chao Chen
- Tianjin Institute of Industrial Biotechnology Chinese Academy of Sciences West 7th Avenue, Tianjin Airport Economic Area Tianjin 300308 China
| | - Aiping Huang
- Tianjin Institute of Industrial Biotechnology Chinese Academy of Sciences West 7th Avenue, Tianjin Airport Economic Area Tianjin 300308 China
| | - Ruipei Xie
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China
- School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049 China
| | - Guosheng Wang
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China
| | - Jiangrui Zhu
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China
- School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049 China
| | - Yuchuan Wang
- Shenzhen Institute of Transfusion Medicine Shenzhen Blood Center Futian District Shenzhen 518052 China
| | - Xiaohong Liu
- Institute of Biophysics Chinese Academy of Sciences Datun Road, Chaoyang District Beijing 100101 China
| | - Wei Zhuang
- State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences Fuzhou 350002 China
- Institute of urban environment Chinese Academy of Sciences Xiamen Fujian 361021 China
| | - Yunliang Li
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China
- School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049 China
- Songshan Lake Materials Laboratory Dongguan Guangdong 523808 China
| | - Jiangyun Wang
- Institute of Biophysics Chinese Academy of Sciences Datun Road, Chaoyang District Beijing 100101 China
- Shenzhen Institute of Transfusion Medicine Shenzhen Blood Center Futian District Shenzhen 518052 China
- School of Life Sciences University of Chinese Academy of Sciences Yuquan Road, Shijingshan District Beijing 100049 China
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15
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Wang L, Zhang J, Han MJ, Zhang L, Chen C, Huang A, Xie R, Wang G, Zhu J, Wang Y, Liu X, Zhuang W, Li Y, Wang J. A Genetically Encoded Two-Dimensional Infrared Probe for Enzyme Active-Site Dynamics. Angew Chem Int Ed Engl 2021; 60:11143-11147. [PMID: 33644946 DOI: 10.1002/anie.202016880] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 02/10/2021] [Indexed: 11/08/2022]
Abstract
While two-dimensional infrared (2D-IR) spectroscopy is uniquely suitable for monitoring femtosecond (fs) to picosecond (ps) water dynamics around static protein structures, its utility for probing enzyme active-site dynamics is limited due to the lack of site-specific 2D-IR probes. We demonstrate the genetic incorporation of a novel 2D-IR probe, m-azido-L-tyrosine (N3Y) in the active-site of DddK, an iron-dependent enzyme that catalyzes the conversion of dimethylsulfoniopropionate to dimethylsulphide. Our results show that both the oxidation of active-site iron to FeIII , and the addition of denaturation reagents, result in significant decrease in enzyme activity and active-site water motion confinement. As tyrosine residues play important roles, including as general acids and bases, and electron transfer agents in many key enzymes, the genetically encoded 2D-IR probe N3Y should be broadly applicable to investigate how the enzyme active-site motions at the fs-ps time scale direct reaction pathways to facilitating specific chemical reactions.
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Affiliation(s)
- Li Wang
- School of Life Sciences, University of Chinese Academy of Sciences, Yuquan Road, Shijingshan District, Beijing, 100049, China.,Institute of Biophysics, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing, 100101, China
| | - Jia Zhang
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ming-Jie Han
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, China.,Shenzhen Institute of Transfusion Medicine, Shenzhen Blood Center, Futian District, Shenzhen, 518052, China
| | - Lu Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China
| | - Chao Chen
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, China
| | - Aiping Huang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, China
| | - Ruipei Xie
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guosheng Wang
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Jiangrui Zhu
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuchuan Wang
- Shenzhen Institute of Transfusion Medicine, Shenzhen Blood Center, Futian District, Shenzhen, 518052, China
| | - Xiaohong Liu
- Institute of Biophysics, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing, 100101, China
| | - Wei Zhuang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China.,Institute of urban environment, Chinese Academy of Sciences, Xiamen, Fujian, 361021, China
| | - Yunliang Li
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.,Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Jiangyun Wang
- Institute of Biophysics, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing, 100101, China.,Shenzhen Institute of Transfusion Medicine, Shenzhen Blood Center, Futian District, Shenzhen, 518052, China.,School of Life Sciences, University of Chinese Academy of Sciences, Yuquan Road, Shijingshan District, Beijing, 100049, China
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16
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Ganser LR, Chu CC, Bogerd HP, Kelly ML, Cullen BR, Al-Hashimi HM. Probing RNA Conformational Equilibria within the Functional Cellular Context. Cell Rep 2021; 30:2472-2480.e4. [PMID: 32101729 DOI: 10.1016/j.celrep.2020.02.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 12/24/2019] [Accepted: 01/31/2020] [Indexed: 12/17/2022] Open
Abstract
Low-abundance short-lived non-native conformations referred to as excited states (ESs) are increasingly observed in vitro and implicated in the folding and biological activities of regulatory RNAs. We developed an approach for assessing the relative abundance of RNA ESs within the functional cellular context. Nuclear magnetic resonance (NMR) spectroscopy was used to estimate the degree to which substitution mutations bias conformational equilibria toward the inactive ES in vitro. The cellular activity of the ES-stabilizing mutants was used as an indirect measure of the conformational equilibria within the functional cellular context. Compensatory mutations that restore the ground-state conformation were used to control for changes in sequence. Using this approach, we show that the ESs of two regulatory RNAs from HIV-1, the transactivation response element (TAR) and the Rev response element (RRE), likely form in cells with abundances comparable to those measured in vitro, and their targeted stabilization may provide an avenue for developing anti-HIV therapeutics.
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Affiliation(s)
- Laura R Ganser
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Chia-Chieh Chu
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Hal P Bogerd
- Department of Molecular Genetics and Microbiology, Center for Virology, Duke University Medical Center, Durham, NC 27710, USA
| | - Megan L Kelly
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Bryan R Cullen
- Department of Molecular Genetics and Microbiology, Center for Virology, Duke University Medical Center, Durham, NC 27710, USA.
| | - Hashim M Al-Hashimi
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
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17
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Huysmans GHM, Ciftci D, Wang X, Blanchard SC, Boudker O. The high-energy transition state of the glutamate transporter homologue GltPh. EMBO J 2021; 40:e105415. [PMID: 33185289 PMCID: PMC7780239 DOI: 10.15252/embj.2020105415] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 09/16/2020] [Accepted: 09/18/2020] [Indexed: 01/03/2023] Open
Abstract
Membrane transporters mediate cellular uptake of nutrients, signaling molecules, and drugs. Their overall mechanisms are often well understood, but the structural features setting their rates are mostly unknown. Earlier single-molecule fluorescence imaging of the archaeal model glutamate transporter homologue GltPh from Pyrococcus horikoshii suggested that the slow conformational transition from the outward- to the inward-facing state, when the bound substrate is translocated from the extracellular to the cytoplasmic side of the membrane, is rate limiting to transport. Here, we provide insight into the structure of the high-energy transition state of GltPh that limits the rate of the substrate translocation process. Using bioinformatics, we identified GltPh gain-of-function mutations in the flexible helical hairpin domain HP2 and applied linear free energy relationship analysis to infer that the transition state structurally resembles the inward-facing conformation. Based on these analyses, we propose an approach to search for allosteric modulators for transporters.
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Affiliation(s)
- Gerard H M Huysmans
- Department of Physiology and BiophysicsWeill Cornell MedicineNew YorkNYUSA
- Mass Spectrometry for Biology Unit, USR 2000CNRSInstitut PasteurParisFrance
| | - Didar Ciftci
- Department of Physiology and BiophysicsWeill Cornell MedicineNew YorkNYUSA
- Tri‐Institutional Training Program in Chemical BiologyNew YorkNYUSA
| | - Xiaoyu Wang
- Department of Physiology and BiophysicsWeill Cornell MedicineNew YorkNYUSA
| | - Scott C Blanchard
- Department of Physiology and BiophysicsWeill Cornell MedicineNew YorkNYUSA
- Tri‐Institutional Training Program in Chemical BiologyNew YorkNYUSA
- St. Jude Children’s Research HospitalMemphisTNUSA
| | - Olga Boudker
- Department of Physiology and BiophysicsWeill Cornell MedicineNew YorkNYUSA
- Tri‐Institutional Training Program in Chemical BiologyNew YorkNYUSA
- Howard Hughes Medical InstituteChevy ChaseMDUSA
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18
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Kundu P, Saha S, Gangopadhyay G. Kinetics of Allosteric Inhibition of Single Enzyme by Product Molecules. J Phys Chem B 2020; 124:11793-11801. [DOI: 10.1021/acs.jpcb.0c08392] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Prasanta Kundu
- S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India
| | - Soma Saha
- Department of Chemistry, Presidency University, 86/1 College Street, Kolkata 700073, India
| | - Gautam Gangopadhyay
- S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India
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19
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Kumar N, Marx D. On the Adaptability of the Chemical Reaction of Hairpin Ribozyme to High Pressures. J Phys Chem Lett 2020; 11:9298-9303. [PMID: 33085887 DOI: 10.1021/acs.jpclett.0c02902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The discovery of RNA enzymes, ribozymes, provided strong support to the RNA world hypothesis suggesting that early life evolved from RNAs able to both store genetic information and catalyze biochemical reactions. Moreover, evidence is accumulating that primitive life might have emerged in deep-sea environments and, thus, at high hydrostatic pressures. If true, ribozymes should be able to function under those pressures. In this work, we ask if and possibly how ribozymes could function at high pressures. To this end, we specifically focus on the chemical reaction steps of the self-cleavage catalysis of hairpin ribozyme by employing extensive QM/MM metadynamics simulations. We find that the reaction scenario at high pressures is vastly different than that at ambient conditions, yet the rate-limiting reaction barrier and, thus, the reaction rate are only marginally affected. Therefore, the results indeed suggest that ribozymes would function at high pressures but by following a vastly different reaction scenario.
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Affiliation(s)
- Narendra Kumar
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
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20
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Kumar N, Marx D. Deciphering the Self-Cleavage Reaction Mechanism of Hairpin Ribozyme. J Phys Chem B 2020; 124:4906-4918. [PMID: 32453954 DOI: 10.1021/acs.jpcb.0c03768] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hairpin ribozyme catalyzes the reversible self-cleavage of phosphodiester bonds which plays prominent roles in key biological processes involving RNAs. Despite impressive advances on ribozymatic self-cleavage, critical aspects of its molecular reaction mechanism remain controversially debated. Here, we generate and analyze the multidimensional free energy landscape that underlies the reaction using extensive QM/MM metadynamics simulations to investigate in detail the full self-cleavage mechanism. This allows us to answer several pertinent yet controversial questions concerning activation of the 2'-OH group, the mechanistic role of water molecules present in the active site, and the full reaction pathway including the structures of transition states and intermediates. Importantly, we find that a sufficiently unrestricted reaction subspace must be mapped using accelerated sampling methods in order to compute the underlying free energy landscape. It is shown that lower-dimensional sampling where the bond formation and cleavage steps are coupled does not allow the system to sufficiently explore the landscape. On the basis of a three-dimensional free energy surface spanned by flexible generalized coordinates, we find that 2'-OH is indirectly activated by adjacent G8 nucleobase in conjunction with stabilizing H-bonding involving water. This allows the proton of the 2'-OH group to directly migrate toward the 5'-leaving group via a nonbridging oxygen of the phosphodiester link. At variance with similar enzymatic processes where water wires connected to protonable side chains of the protein matrix act as transient proton shuttles, no such de/reprotonation events of water molecules are found to be involved in this ribozymatic transesterification. Overall, our results support an acid-catalyzed reaction mechanism where A38 nucleobase directly acts as an acid whereas G8, in stark contrast, participates only indirectly via stabilizing the nascent nucleophile for subsequent attack. Moreover, we conclude that self-cleavage of hairpin ribozyme follows an AN + DN two-step associative pathway where the rate-determining step is the cleavage of the phosphodiester bond. These results provide a major advancement in our understanding of the unique catalytic mechanism of hairpin ribozyme which will fruitfully impact on the design of synthetic ribozymes.
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Affiliation(s)
- Narendra Kumar
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
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21
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Profile of Xiaowei Zhuang, winner of the 2020 Vilcek Prize in Biomedical Science. Proc Natl Acad Sci U S A 2020; 117:9660-9664. [DOI: 10.1073/pnas.2004997117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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22
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Ciftci D, Huysmans GHM, Wang X, He C, Terry D, Zhou Z, Fitzgerald G, Blanchard SC, Boudker O. Single-molecule transport kinetics of a glutamate transporter homolog shows static disorder. SCIENCE ADVANCES 2020; 6:eaaz1949. [PMID: 32523985 PMCID: PMC7259943 DOI: 10.1126/sciadv.aaz1949] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 03/26/2020] [Indexed: 06/11/2023]
Abstract
Kinetic properties of membrane transporters are typically poorly defined because high-resolution functional assays analogous to single-channel recordings are lacking. Here, we measure single-molecule transport kinetics of a glutamate transporter homolog from Pyrococcus horikoshii, GltPh, using fluorescently labeled periplasmic amino acid binding protein as a fluorescence resonance energy transfer-based sensor. We show that individual transporters can function at rates varying by at least two orders of magnitude that persist for multiple turnovers. A gain-of-function mutant shows increased population of the fast-acting transporters, leading to a 10-fold increase in the mean transport rate. These findings, which are broadly consistent with earlier single-molecule measurements of GltPh conformational dynamics, suggest that GltPh transport is defined by kinetically distinct populations that exhibit long-lasting "molecular memory."
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Affiliation(s)
- Didar Ciftci
- Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA
- Tri-Institutional Training Program in Chemical Biology, New York, NY 10065, USA
| | - Gerard H. M. Huysmans
- Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA
| | - Xiaoyu Wang
- Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA
| | - Changhao He
- Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA
| | - Daniel Terry
- Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA
| | - Zhou Zhou
- Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA
| | - Gabriel Fitzgerald
- Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA
| | - Scott C. Blanchard
- Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA
- Tri-Institutional Training Program in Chemical Biology, New York, NY 10065, USA
| | - Olga Boudker
- Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA
- Tri-Institutional Training Program in Chemical Biology, New York, NY 10065, USA
- Howard Hughes Medical Institute, Weill Cornell Medicine, New York, NY, 10065, USA
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23
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24
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Li Y, Zhao L, Yao Y, Guo X. Single-Molecule Nanotechnologies: An Evolution in Biological Dynamics Detection. ACS APPLIED BIO MATERIALS 2019; 3:68-85. [DOI: 10.1021/acsabm.9b00840] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yu Li
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Lihua Zhao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Yuan Yao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Xuefeng Guo
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
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25
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Mao X, Li Q, Zuo X, Fan C. Catalytic Nucleic Acids for Bioanalysis. ACS APPLIED BIO MATERIALS 2019; 3:2674-2685. [PMID: 35025402 DOI: 10.1021/acsabm.9b00928] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Xiuhai Mao
- Institute of Molecular Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Qian Li
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaolei Zuo
- Institute of Molecular Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Chunhai Fan
- Institute of Molecular Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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26
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Lee TH. Physical Chemistry of Epigenetics: Single-Molecule Investigations. J Phys Chem B 2019; 123:8351-8362. [PMID: 31404497 PMCID: PMC6790939 DOI: 10.1021/acs.jpcb.9b06214] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/03/2019] [Indexed: 02/06/2023]
Abstract
The nucleosome is the fundamental building block of the eukaryotic genome, composed of an ∼147 base-pair DNA fragment wrapping around an octameric histone protein core. DNA and histone proteins are targets of enzymatic chemical modifications that serve as signals for gene regulation. These modifications are often referred to as epigenetic modifications that govern gene activities without altering the DNA sequence. Although the term epigenetics initially required inheritability, it now frequently includes noninherited histone modifications associated with gene regulation. Important epigenetic modifications for healthy cell growth and proliferation include DNA methylation, histone acetylation, methylation, phosphorylation, ubiquitination, and SUMOylation (SUMO = Small Ubiquitin-like Modifier). Our research focuses on the biophysical roles of these modifications in altering the structure and structural dynamics of the nucleosome and their implications in gene regulation mechanisms. As the changes are subtle and complex, we employ various single-molecule fluorescence approaches for their investigations. Our investigations revealed that these modifications induce changes in the structure and structural dynamics of the nucleosome and their thermodynamic and kinetic stabilities. We also suggested the implications of these changes in gene regulation mechanisms that are the foci of our current and future research.
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Affiliation(s)
- Tae-Hee Lee
- Department of Chemistry, The
Pennsylvania State University, University Park 16803, Pennsylvania, United States
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27
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Wan W, Li ADQ. Discovery of a New Light-Molecule Interaction: Supracence Reveals What Is Missing in Fluorescence Imaging. Angew Chem Int Ed Engl 2019; 58:13739-13743. [PMID: 31269318 DOI: 10.1002/anie.201906499] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Indexed: 11/07/2022]
Abstract
The currently understood principles about light-molecule interactions are limited, and thus scientific scope beyond current theories is rarely harvested. Herein we demonstrate supracence phenomena, in which the emitted photons have more energy than the absorbed photons. The extra energy comes from couplings of the absorbed and emitted photon to molecular phonons, whose potentials are constantly exchanging with molecular quantum energy and the environment. Thus, supracence is a linear optical process rather than a nonlinear optical process, such as second harmonic generation. Because supracence results in cooled molecular phonons and thus cooled molecules, behavior opposite to that of hot fluorescing emitters is expected. This report reveals certain supracence principles while contrasting fluorescence with supracence in high-resolution imaging.
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Affiliation(s)
- Wei Wan
- Department of Chemistry, Washington State University, Pullman, WA, 99164, USA
| | - Alexander D Q Li
- Department of Chemistry, Washington State University, Pullman, WA, 99164, USA
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28
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Suddala KC, Price IR, Dandpat SS, Janeček M, Kührová P, Šponer J, Banáš P, Ke A, Walter NG. Local-to-global signal transduction at the core of a Mn 2+ sensing riboswitch. Nat Commun 2019; 10:4304. [PMID: 31541094 PMCID: PMC6754395 DOI: 10.1038/s41467-019-12230-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 08/28/2019] [Indexed: 01/01/2023] Open
Abstract
The widespread Mn2+-sensing yybP-ykoY riboswitch controls the expression of bacterial Mn2+ homeostasis genes. Here, we first determine the crystal structure of the ligand-bound yybP-ykoY riboswitch aptamer from Xanthomonas oryzae at 2.96 Å resolution, revealing two conformations with docked four-way junction (4WJ) and incompletely coordinated metal ions. In >100 µs of MD simulations, we observe that loss of divalents from the core triggers local structural perturbations in the adjacent docking interface, laying the foundation for signal transduction to the regulatory switch helix. Using single-molecule FRET, we unveil a previously unobserved extended 4WJ conformation that samples transient docked states in the presence of Mg2+. Only upon adding sub-millimolar Mn2+, however, can the 4WJ dock stably, a feature lost upon mutation of an adenosine contacting Mn2+ in the core. These observations illuminate how subtly differing ligand preferences of competing metal ions become amplified by the coupling of local with global RNA dynamics.
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Affiliation(s)
- Krishna C Suddala
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Ian R Price
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14850, USA
| | - Shiba S Dandpat
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Michal Janeček
- Institute of Biophysics of the Czech Academy of Sciences, Kralovopolská 135, Brno, 612 65, Czech Republic
- Department of Physical Chemistry, Faculty of Science, Palacký University, tř. 17 listopadu 12, Olomouc, 771 46, Czech Republic
| | - Petra Kührová
- Department of Physical Chemistry, Faculty of Science, Palacký University, tř. 17 listopadu 12, Olomouc, 771 46, Czech Republic
- Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University, tř. 17 listopadu 12, Olomouc, 771 46, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences, Kralovopolská 135, Brno, 612 65, Czech Republic
- Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University, tř. 17 listopadu 12, Olomouc, 771 46, Czech Republic
| | - Pavel Banáš
- Institute of Biophysics of the Czech Academy of Sciences, Kralovopolská 135, Brno, 612 65, Czech Republic
- Department of Physical Chemistry, Faculty of Science, Palacký University, tř. 17 listopadu 12, Olomouc, 771 46, Czech Republic
- Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University, tř. 17 listopadu 12, Olomouc, 771 46, Czech Republic
| | - Ailong Ke
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14850, USA.
| | - Nils G Walter
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA.
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29
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Jansson LI, Stone MD. Single-Molecule Analysis of Reverse Transcriptase Enzymes. Cold Spring Harb Perspect Biol 2019; 11:11/9/a032458. [PMID: 31481455 DOI: 10.1101/cshperspect.a032458] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The original discovery of enzymes that synthesize DNA using an RNA template appeared to contradict the central dogma of biology, in which information is transferred, in a unidirectional way, from DNA genes into RNA molecules. The paradigm-shifting discovery of RNA-dependent DNA polymerases, also called reverse transcriptases (RTs), reshaped existing views for how cells function; however, the scope of the impact RTs impose on biology had yet to be realized. In the decades of research since the early 1970s, the biomedical and biotechnological significance of retroviral RTs, as well as the evolutionarily related telomerase enzyme, has become exceedingly clear. One common theme that has emerged in the course of RT-related research is the central role of nucleic acid binding and dynamics during enzyme function. However, directly interrogating these dynamic properties is challenging because of the stochastic properties of biological macromolecules. In this review, we describe how the development of single-molecule biophysical techniques has opened new windows through which to observe the dynamic behavior of this remarkable class of enzymes. Specifically, we focus on how the powerful single-molecule Förster resonance energy transfer (FRET) method has been exploited to study the structure and function of the human immunodeficiency virus (HIV) RT and telomerase ribonucleoprotein (RNP) enzymes. These exciting studies have refined our understanding of RT catalysis, have revealed unforeseen structural rearrangements between RTs and their nucleic acid substrates, and have helped to characterize the mode of action of RT-inhibiting drugs. We conclude with a discussion of how the ongoing development of single-molecule technologies will continue to empower researchers to probe RT mechanisms in new and exciting ways.
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Affiliation(s)
- Linnea I Jansson
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, California 95064.,The Center for Molecular Biology of RNA, University of California, Santa Cruz, California 95064
| | - Michael D Stone
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064.,The Center for Molecular Biology of RNA, University of California, Santa Cruz, California 95064
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30
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Kumar N, Marx D. How do ribozymes accommodate additional water molecules upon hydrostatic compression deep into the kilobar pressure regime? Biophys Chem 2019; 252:106192. [DOI: 10.1016/j.bpc.2019.106192] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/23/2019] [Accepted: 05/23/2019] [Indexed: 12/19/2022]
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31
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Wan W, Li ADQ. Discovery of a New Light–Molecule Interaction: Supracence Reveals What Is Missing in Fluorescence Imaging. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201906499] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Wei Wan
- Department of Chemistry Washington State University Pullman WA 99164 USA
| | - Alexander D. Q. Li
- Department of Chemistry Washington State University Pullman WA 99164 USA
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32
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Kumar N, Marx D. Mechanistic role of nucleobases in self-cleavage catalysis of hairpin ribozyme at ambient versus high-pressure conditions. Phys Chem Chem Phys 2019; 20:20886-20898. [PMID: 30067263 DOI: 10.1039/c8cp03142h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Ribozymes catalyze the site-specific self-cleavage of intramolecular phosphodiester bonds. Initially thought to act as metalloenzymes, they are now known to be functional even in the absence of divalent metal ions and specific nucleobases directly participate in the self-cleavage reaction. Here, we use extensive replica exchange molecular dynamics simulations to probe the precise mechanistic role of nucleobases by simulating precatalytic reactant and active precursor states of a hairpin ribozyme along its reaction path at ambient as well as high-pressure conditions. The results provide novel key insights into the self-cleavage of ribozymes. We find that deprotonation of the hydroxyl group is crucial and might be the penultimate step to the self-cleavage. The G8 nucleobase is found to stabilize the activated precursor into inline arrangement for facile nucleophilic attack of the scissile phosphate only after deprotonation of the hydroxyl group. The protonated A38 nucleobase, in contrast, mainly acts a proton donor to the O5'-oxygen leaving group that eventually leads to the self-cleavage. Indeed, systematic high-pressure simulations of catalytically relevant states confirm these findings and, moreover, provide support to the role of ribozymes as piezophilic biocatalysts with regard to their relevance in early life under extreme conditions in the realm of RNA world hypothesis.
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Affiliation(s)
- Narendra Kumar
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany.
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33
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Qiu K, Fato TP, Yuan B, Long YT. Toward Precision Measurement and Manipulation of Single-Molecule Reactions by a Confined Space. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1805426. [PMID: 30924293 DOI: 10.1002/smll.201805426] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/28/2019] [Indexed: 06/09/2023]
Abstract
All chemical reactions can be divided into a series of single molecule reactions (SMRs), the elementary steps that involve only isomerization of, dissociation from, and addition to an individual molecule. Analyzing SMRs is of paramount importance to identify the intrinsic molecular mechanism of a complex chemical reaction, which is otherwise implausible to reveal in an ensemble fashion, owing to the significant static and dynamic heterogeneity of real-world chemical systems. The single-molecule measurement and manipulation methods developed recently are playing an increasingly irreplaceable role to detect and recognize short-lived intermediates, visualize their transient existence, and determinate the kinetics and dynamics of single bond breaking and formation. Notably, none of the above SMRs characterizations can be realized without the aid of a confined space. Therefore, this Review aims to highlight the recent progress in the development of confined space enabled single-molecule sensing, imaging, and tuning methods to study chemical reactions. Future prospects of SMRs research are also included, including a push toward the physical limit on transduction of information to signals and vice versa, transmission and recording of signals, computational modeling and simulation, and rational design of a confined space for precise SMRs.
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Affiliation(s)
- Kaipei Qiu
- School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Tano Patrice Fato
- School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Bo Yuan
- School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Yi-Tao Long
- School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
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Hieronymus R, Müller S. Engineering of hairpin ribozyme variants for RNA recombination and splicing. Ann N Y Acad Sci 2019; 1447:135-143. [PMID: 30941784 DOI: 10.1111/nyas.14052] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 02/13/2019] [Accepted: 02/20/2019] [Indexed: 11/28/2022]
Abstract
The hairpin ribozyme is a small, naturally occurring RNA that catalyzes the reversible cleavage of RNA substrates. Among the small endonucleolytic ribozymes, the hairpin ribozyme possesses the unique feature of the internal equilibrium between cleavage and ligation being shifted toward ligation. This allows control of the reaction outcome by structural design: fragments that are strongly bound to the ribozyme are preferentially ligated, whereas substrates that easily dissociate upon cleavage, such that they are not available for religation, are preferentially cleaved. We have made use of this characteristic feature in engineering a number of hairpin ribozyme variants by programmed conformational design that carry out cascades of cleavage and ligation reactions, and as a result mediate more complex RNA processing reactions. Here, we review our work on the engineering of hairpin ribozyme variants for RNA recombination and regular and back-splicing, and discuss the relevance of such activities in early life.
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Affiliation(s)
| | - Sabine Müller
- Institut für Biochemie, Universität Greifswald, Greifswald, Germany
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35
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Xu Y, Gao Y, Su Y, Sun L, Xing F, Fan C, Li D. Single-Molecule Studies of Allosteric Inhibition of Individual Enzyme on a DNA Origami Reactor. J Phys Chem Lett 2018; 9:6786-6794. [PMID: 30412409 DOI: 10.1021/acs.jpclett.8b02992] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Unraveling the conformational changes of enzymes together with inhibition kinetics during an enzymatic reaction has great potential in screening therapeutic candidates; however, it remains challenging due to the transient nature of each intermediate step. We report our study on the noncompetitive inhibition of horseradish peroxidase with single-turnover resolution using single-molecule fluorescence microscopy. By introducing DNA origami as an addressable nanoreactor, we observe the coexistence of nascent-formed fluorescent product on both catalytic and docking sites. We further propose a single-molecule kinetic model to reveal the interplay between product generation and noncompetitive inhibition and find three distinct inhibitor releasing pathways. Moreover, the kinetic isotope effect experiment indicates a strong correlation between catalytic and docking sites, suggesting an allosteric conformational change in noncompetitive inhibition. A memory effect is also observed. This work provides an in-depth understanding of the correlation between enzyme behavior and enzymatic conformational fluctuation, substrate conversion, and product releasing pathway and kinetics.
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Affiliation(s)
- Yan Xu
- School of Chemistry and Molecular Engineering , East China Normal University , Shanghai 200241 , China
- Division of Physical Biology & Bioimaging Center, Shanghai Synchrotron Radiation Facility, Key Laboratory of Interfacial Physics and Technology , Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800 , China
- National Engineering Research Center for Nanotechnology , Shanghai 200241 , China
| | - Yanjing Gao
- Division of Physical Biology & Bioimaging Center, Shanghai Synchrotron Radiation Facility, Key Laboratory of Interfacial Physics and Technology , Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Yingying Su
- School of Chemistry and Molecular Engineering , East China Normal University , Shanghai 200241 , China
- Department of Chemistry, College of Science , Shanghai University , Shanghai 200444 , China
| | - Lele Sun
- Division of Physical Biology & Bioimaging Center, Shanghai Synchrotron Radiation Facility, Key Laboratory of Interfacial Physics and Technology , Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Feifei Xing
- Department of Chemistry, College of Science , Shanghai University , Shanghai 200444 , China
| | - Chunhai Fan
- Division of Physical Biology & Bioimaging Center, Shanghai Synchrotron Radiation Facility, Key Laboratory of Interfacial Physics and Technology , Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800 , China
| | - Di Li
- School of Chemistry and Molecular Engineering , East China Normal University , Shanghai 200241 , China
- Division of Physical Biology & Bioimaging Center, Shanghai Synchrotron Radiation Facility, Key Laboratory of Interfacial Physics and Technology , Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800 , China
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36
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Ray S, Chauvier A, Walter NG. Kinetics coming into focus: single-molecule microscopy of riboswitch dynamics. RNA Biol 2018; 16:1077-1085. [PMID: 30328748 DOI: 10.1080/15476286.2018.1536594] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Riboswitches are dynamic RNA motifs that are mostly embedded in the 5'-untranslated regions of bacterial mRNAs, where they regulate gene expression transcriptionally or translationally by undergoing conformational changes upon binding of a small metabolite or ion. Due to the small size of typical ligands, relatively little free energy is available from ligand binding to overcome the often high energetic barrier of reshaping RNA structure. Instead, most riboswitches appear to take advantage of the directional and hierarchical folding of RNA by employing the ligand as a structural 'linchpin' to adjust the kinetic partitioning between alternate folds. In this model, even small, local structural and kinetic effects of ligand binding can cascade into global RNA conformational changes affecting gene expression. Single-molecule (SM) microscopy tools are uniquely suited to study such kinetically controlled RNA folding since they avoid the ensemble averaging of bulk techniques that loses sight of unsynchronized, transient, and/or multi-state kinetic behavior. This review summarizes how SM methods have begun to unravel riboswitch-mediated gene regulation.
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Affiliation(s)
- Sujay Ray
- a Single Molecule Analysis Group, Department of Chemistry, University of Michigan , Ann Arbor , MI , USA
| | - Adrien Chauvier
- a Single Molecule Analysis Group, Department of Chemistry, University of Michigan , Ann Arbor , MI , USA
| | - Nils G Walter
- a Single Molecule Analysis Group, Department of Chemistry, University of Michigan , Ann Arbor , MI , USA
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37
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Multi-step fluorescence resonance energy transfer between the fluorophores via cosolubilization in cationic, anionic and non-ionic micelles. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2018.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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38
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Kienle DF, Falatach RM, Kaar JL, Schwartz DK. Correlating Structural and Functional Heterogeneity of Immobilized Enzymes. ACS NANO 2018; 12:8091-8103. [PMID: 30067333 DOI: 10.1021/acsnano.8b02956] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Many nanobiotechnology applications rely on stable and efficient integration of functional biomacromolecules with synthetic nanomaterials. Unfortunately, the reasons for the ubiquitous loss of activity of immobilized enzymes remain poorly understood due to the difficulty in distinguishing between distinct molecular-level mechanisms. Here, we employ complementary single-molecule fluorescence methods that independently measure the impact of immobilization on the structure and function ( i. e., substrate binding kinetics) of nitroreductase (NfsB). Stochastic statistical modeling methods were used to unambiguously quantify the effects of immobilized NfsB structural dynamics on function, allowing us to explicitly separate effects due to conformation and accessibility. Interestingly, we found that nonspecifically tethered NfsB exhibited enhanced stability compared to site-specifically tethered NfsB; however, the folded state of site-specifically tethered NfsB had faster substrate binding rates, suggesting improved active site accessibility. This demonstrated an unexpected intrinsic trade-off associated with competing bioconjugation methods, suggesting that it may be necessary to balance conformational stability versus active site accessibility. This nuanced view of the impact of immobilization will facilitate a rational approach to the integration of enzymes with synthetic nanomaterials.
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Affiliation(s)
- Daniel F Kienle
- Department of Chemical and Biological Engineering , University of Colorado , Boulder , Colorado 80309 , United States
| | - Rebecca M Falatach
- Department of Chemical and Biological Engineering , University of Colorado , Boulder , Colorado 80309 , United States
| | - Joel L Kaar
- Department of Chemical and Biological Engineering , University of Colorado , Boulder , Colorado 80309 , United States
| | - Daniel K Schwartz
- Department of Chemical and Biological Engineering , University of Colorado , Boulder , Colorado 80309 , United States
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39
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Hadzic MCAS, Börner R, König SLB, Kowerko D, Sigel RKO. Reliable State Identification and State Transition Detection in Fluorescence Intensity-Based Single-Molecule Förster Resonance Energy-Transfer Data. J Phys Chem B 2018; 122:6134-6147. [PMID: 29737844 DOI: 10.1021/acs.jpcb.7b12483] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Single-molecule Förster resonance energy transfer (smFRET) is a powerful technique to probe biomolecular structure and dynamics. A popular implementation of smFRET consists of recording fluorescence intensity time traces of surface-immobilized, chromophore-tagged molecules. This approach generates large and complex data sets, the analysis of which is to date not standardized. Here, we address a key challenge in smFRET data analysis: the generation of thermodynamic and kinetic models that describe with statistical rigor the behavior of FRET trajectories recorded from surface-tethered biomolecules in terms of the number of FRET states, the corresponding mean FRET values, and the kinetic rates at which they interconvert. For this purpose, we first perform Monte Carlo simulations to generate smFRET trajectories, in which a relevant space of experimental parameters is explored. Then, we provide an account on current strategies to achieve such model selection, as well as a quantitative assessment of their performances. Specifically, we evaluate the performance of each algorithm (change-point analysis, STaSI, HaMMy, vbFRET, and ebFRET) with respect to accuracy, reproducibility, and computing time, which yields a range of algorithm-specific referential benchmarks for various data qualities. Data simulation and analysis were performed with our MATLAB-based multifunctional analysis software for handling smFRET data (MASH-FRET).
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Affiliation(s)
| | | | | | - Danny Kowerko
- Department of Computer Science , Chemnitz University of Technology , 09111 Chemnitz , Germany
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40
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SUN LL, SU YY, GAO YJ, Li W, LYU H, LI B, LI D. Progresses of Single Molecular Fluorescence Resonance Energy Transfer in Studying Biomacromolecule Dynamic Process. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2018. [DOI: 10.1016/s1872-2040(18)61088-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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41
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Hierarchical mechanism of amino acid sensing by the T-box riboswitch. Nat Commun 2018; 9:1896. [PMID: 29760498 PMCID: PMC5951919 DOI: 10.1038/s41467-018-04305-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 04/16/2018] [Indexed: 11/08/2022] Open
Abstract
In Gram-positive bacteria, T-box riboswitches control gene expression to maintain the cellular pools of aminoacylated tRNAs essential for protein biosynthesis. Co-transcriptional binding of an uncharged tRNA to the riboswitch stabilizes an antiterminator, allowing transcription read-through, whereas an aminoacylated tRNA does not. Recent structural studies have resolved two contact points between tRNA and Stem-I in the 5' half of the T-box riboswitch, but little is known about the mechanism empowering transcriptional control by a small, distal aminoacyl modification. Using single-molecule fluorescence microscopy, we have probed the kinetic and structural underpinnings of tRNA binding to a glycyl T-box riboswitch. We observe a two-step mechanism where fast, dynamic recruitment of tRNA by Stem-I is followed by ultra-stable anchoring by the downstream antiterminator, but only without aminoacylation. Our results support a hierarchical sensing mechanism wherein dynamic global binding of the tRNA body is followed by localized readout of its aminoacylation status by snap-lock-based trapping.
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42
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Šponer J, Bussi G, Krepl M, Banáš P, Bottaro S, Cunha RA, Gil-Ley A, Pinamonti G, Poblete S, Jurečka P, Walter NG, Otyepka M. RNA Structural Dynamics As Captured by Molecular Simulations: A Comprehensive Overview. Chem Rev 2018; 118:4177-4338. [PMID: 29297679 PMCID: PMC5920944 DOI: 10.1021/acs.chemrev.7b00427] [Citation(s) in RCA: 336] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Indexed: 12/14/2022]
Abstract
With both catalytic and genetic functions, ribonucleic acid (RNA) is perhaps the most pluripotent chemical species in molecular biology, and its functions are intimately linked to its structure and dynamics. Computer simulations, and in particular atomistic molecular dynamics (MD), allow structural dynamics of biomolecular systems to be investigated with unprecedented temporal and spatial resolution. We here provide a comprehensive overview of the fast-developing field of MD simulations of RNA molecules. We begin with an in-depth, evaluatory coverage of the most fundamental methodological challenges that set the basis for the future development of the field, in particular, the current developments and inherent physical limitations of the atomistic force fields and the recent advances in a broad spectrum of enhanced sampling methods. We also survey the closely related field of coarse-grained modeling of RNA systems. After dealing with the methodological aspects, we provide an exhaustive overview of the available RNA simulation literature, ranging from studies of the smallest RNA oligonucleotides to investigations of the entire ribosome. Our review encompasses tetranucleotides, tetraloops, a number of small RNA motifs, A-helix RNA, kissing-loop complexes, the TAR RNA element, the decoding center and other important regions of the ribosome, as well as assorted others systems. Extended sections are devoted to RNA-ion interactions, ribozymes, riboswitches, and protein/RNA complexes. Our overview is written for as broad of an audience as possible, aiming to provide a much-needed interdisciplinary bridge between computation and experiment, together with a perspective on the future of the field.
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Affiliation(s)
- Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences , Kralovopolska 135 , Brno 612 65 , Czech Republic
| | - Giovanni Bussi
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Miroslav Krepl
- Institute of Biophysics of the Czech Academy of Sciences , Kralovopolska 135 , Brno 612 65 , Czech Republic
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Pavel Banáš
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Sandro Bottaro
- Structural Biology and NMR Laboratory, Department of Biology , University of Copenhagen , Copenhagen 2200 , Denmark
| | - Richard A Cunha
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Alejandro Gil-Ley
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Giovanni Pinamonti
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Simón Poblete
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Petr Jurečka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Nils G Walter
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
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Ray S, Widom JR, Walter NG. Life under the Microscope: Single-Molecule Fluorescence Highlights the RNA World. Chem Rev 2018; 118:4120-4155. [PMID: 29363314 PMCID: PMC5918467 DOI: 10.1021/acs.chemrev.7b00519] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The emergence of single-molecule (SM) fluorescence techniques has opened up a vast new toolbox for exploring the molecular basis of life. The ability to monitor individual biomolecules in real time enables complex, dynamic folding pathways to be interrogated without the averaging effect of ensemble measurements. In parallel, modern biology has been revolutionized by our emerging understanding of the many functions of RNA. In this comprehensive review, we survey SM fluorescence approaches and discuss how the application of these tools to RNA and RNA-containing macromolecular complexes in vitro has yielded significant insights into the underlying biology. Topics covered include the three-dimensional folding landscapes of a plethora of isolated RNA molecules, their assembly and interactions in RNA-protein complexes, and the relation of these properties to their biological functions. In all of these examples, the use of SM fluorescence methods has revealed critical information beyond the reach of ensemble averages.
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Affiliation(s)
| | | | - Nils G. Walter
- Department of Chemistry, Single Molecule Analysis Group, University of Michigan, Ann Arbor, MI 48109, USA
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44
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Daher M, Widom JR, Tay W, Walter NG. Soft Interactions with Model Crowders and Non-canonical Interactions with Cellular Proteins Stabilize RNA Folding. J Mol Biol 2017; 430:509-523. [PMID: 29128594 DOI: 10.1016/j.jmb.2017.10.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 10/22/2017] [Accepted: 10/30/2017] [Indexed: 12/18/2022]
Abstract
Living cells contain diverse biopolymers, creating a heterogeneous crowding environment, the impact of which on RNA folding is poorly understood. Here, we have used single-molecule fluorescence resonance energy transfer to monitor tertiary structure formation of the hairpin ribozyme as a model to probe the effects of polyethylene glycol and yeast cell extract as crowding agents. As expected, polyethylene glycol stabilizes the docked, catalytically active state of the ribozyme, in part through excluded volume effects; unexpectedly, we found evidence that it additionally displays soft, non-specific interactions with the ribozyme. Yeast extract has a profound effect on folding at protein concentrations 1000-fold lower than found intracellularly, suggesting the dominance of specific interactions over volume exclusion. Gel shift assays and affinity pull-down followed by mass spectrometry identified numerous non-canonical RNA-binding proteins that stabilize ribozyme folding; the apparent chaperoning activity of these ubiquitous proteins significantly compensates for the low-counterion environment of the cell.
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Affiliation(s)
- May Daher
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA; Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Julia R Widom
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA; Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Wendy Tay
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA; Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Nils G Walter
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA; Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI 48109-1055, USA.
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45
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Hu J, Liu MH, Li Y, Tang B, Zhang CY. Simultaneous sensitive detection of multiple DNA glycosylases from lung cancer cells at the single-molecule level. Chem Sci 2017; 9:712-720. [PMID: 29629140 PMCID: PMC5869805 DOI: 10.1039/c7sc04296e] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 11/06/2017] [Indexed: 01/05/2023] Open
Abstract
We demonstrate the simultaneous detection of human 8-oxoguanine DNA glycosylase 1 and human alkyladenine DNA glycosylase at the single-molecule level.
DNA glycosylases are involved in the base excision repair pathway, and all mammals express multiple DNA glycosylases to maintain genome stability. However, the simultaneous detection of multiple DNA glycosylase still remains a great challenge. Here, we develop a single-molecule detection method for the simultaneous detection of human 8-oxoguanine DNA glycosylase 1 (hOGG1) and human alkyladenine DNA glycosylase (hAAG) on the basis of DNA glycosylase-mediated cleavage of molecular beacons. We designed a Cy3-labeled molecular beacon modified with 8-oxoguanine (8-oxoG) for a hOGG1 assay and a Cy5-labeled molecular beacon modified with deoxyinosine for a hAAG assay. hOGG1 may catalyze the removal of 8-oxoG from 8-oxoG/C base pairs to generate an apurinic/apyrimidinic (AP) site, and hAAG may catalyze the removal of deoxyinosine from deoxyinosine/T base pairs to generate an AP site. With the assistance of apurinic/apyrimidinic endonuclease (APE1), the cleavage of AP sites results in the cleavage of molecular beacons, with Cy3 indicating the presence of hOGG1 and Cy5 indicating the presence of hAAG. Both of the Cy3 and Cy5 signals can be simply quantified by total internal reflection fluorescence-based single-molecule detection. This method can simultaneously detect multiple DNA glycosylases with a detection limit of 2.23 × 10–6 U μL–1 for hOGG1 and 8.69 × 10–7 U μL–1 for hAAG without the involvement of any target amplification. Moreover, this method can be used for the screening of enzyme inhibitors and the simultaneous detection of hOGG1 and hAAG from lung cancer cells, having great potential for further application in early clinical diagnosis.
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Affiliation(s)
- Juan Hu
- College of Chemistry, Chemical Engineering and Materials Science , Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong , Key Laboratory of Molecular and Nano Probes , Ministry of Education , Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals , Shandong Normal University , Jinan 250014 , China . ; ; ; Fax: +86 531 86180017 ; Tel: +86 531 86186033 ; Tel: +86 531 86180010
| | - Ming-Hao Liu
- College of Chemistry, Chemical Engineering and Materials Science , Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong , Key Laboratory of Molecular and Nano Probes , Ministry of Education , Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals , Shandong Normal University , Jinan 250014 , China . ; ; ; Fax: +86 531 86180017 ; Tel: +86 531 86186033 ; Tel: +86 531 86180010
| | - Ying Li
- School of Medicine , Health Science Center , Shenzhen University , Shenzhen 518060 , China
| | - Bo Tang
- College of Chemistry, Chemical Engineering and Materials Science , Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong , Key Laboratory of Molecular and Nano Probes , Ministry of Education , Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals , Shandong Normal University , Jinan 250014 , China . ; ; ; Fax: +86 531 86180017 ; Tel: +86 531 86186033 ; Tel: +86 531 86180010
| | - Chun-Yang Zhang
- College of Chemistry, Chemical Engineering and Materials Science , Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong , Key Laboratory of Molecular and Nano Probes , Ministry of Education , Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals , Shandong Normal University , Jinan 250014 , China . ; ; ; Fax: +86 531 86180017 ; Tel: +86 531 86186033 ; Tel: +86 531 86180010
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46
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Daher M, Mustoe AM, Morriss-Andrews A, Brooks CL, Walter NG. Tuning RNA folding and function through rational design of junction topology. Nucleic Acids Res 2017; 45:9706-9715. [PMID: 28934478 PMCID: PMC5766210 DOI: 10.1093/nar/gkx614] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 07/05/2017] [Indexed: 01/31/2023] Open
Abstract
Structured RNAs such as ribozymes must fold into specific 3D structures to carry out their biological functions. While it is well-known that architectural features such as flexible junctions between helices help guide RNA tertiary folding, the mechanisms through which junctions influence folding remain poorly understood. We combine computational modeling with single molecule Förster resonance energy transfer (smFRET) and catalytic activity measurements to investigate the influence of junction design on the folding and function of the hairpin ribozyme. Coarse-grained simulations of a wide range of junction topologies indicate that differences in sterics and connectivity, independent of stacking, significantly affect tertiary folding and appear to largely explain previously observed variations in hairpin ribozyme stability. We further use our simulations to identify stabilizing modifications of non-optimal junction topologies, and experimentally validate that a three-way junction variant of the hairpin ribozyme can be stabilized by specific insertion of a short single-stranded linker. Combined, our multi-disciplinary study further reinforces that junction sterics and connectivity are important determinants of RNA folding, and demonstrates the potential of coarse-grained simulations as a tool for rationally tuning and optimizing RNA folding and function.
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Affiliation(s)
- May Daher
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, 930 N. University Avenue, Ann Arbor, MI 48109-1055, USA
| | - Anthony M Mustoe
- Biophysics, University of Michigan, 930 N. University Avenue, Ann Arbor, MI 48109-1055, USA
| | - Alex Morriss-Andrews
- Biophysics, University of Michigan, 930 N. University Avenue, Ann Arbor, MI 48109-1055, USA.,Department of Chemistry, University of Michigan, 930 N. University Avenue, Ann Arbor, MI 48109-1055, USA
| | - Charles L Brooks
- Biophysics, University of Michigan, 930 N. University Avenue, Ann Arbor, MI 48109-1055, USA.,Department of Chemistry, University of Michigan, 930 N. University Avenue, Ann Arbor, MI 48109-1055, USA
| | - Nils G Walter
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, 930 N. University Avenue, Ann Arbor, MI 48109-1055, USA
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47
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Reddy BJ, Tripathy S, Vershinin M, Tanenbaum ME, Xu J, Mattson-Hoss M, Arabi K, Chapman D, Doolin T, Hyeon C, Gross SP. Heterogeneity in kinesin function. Traffic 2017; 18:658-671. [PMID: 28731566 PMCID: PMC11166478 DOI: 10.1111/tra.12504] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/18/2017] [Accepted: 07/18/2017] [Indexed: 12/25/2022]
Abstract
The kinesin family proteins are often studied as prototypical molecular motors; a deeper understanding of them can illuminate regulation of intracellular transport. It is typically assumed that they function identically. Here we find that this assumption of homogeneous function appears incorrect: variation among motors' velocities in vivo and in vitro is larger than the stochastic variation expected for an ensemble of "identical" motors. When moving on microtubules, slow and fast motors are persistently slow, and fast, respectively. We develop theory that provides quantitative criteria to determine whether the observed single-molecule variation is too large to be generated from an ensemble of identical molecules. To analyze such heterogeneity, we group traces into homogeneous sub-ensembles. Motility studies varying the temperature, pH and glycerol concentration suggest at least 2 distinct functional states that are independently affected by external conditions. We end by investigating the functional ramifications of such heterogeneity through Monte-Carlo multi-motor simulations.
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Affiliation(s)
- Babu J.N. Reddy
- Department of Developmental and Cell Biology, University of California, Irvine, CA
| | - Suvranta Tripathy
- Department of Developmental and Cell Biology, University of California, Irvine, CA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Michael Vershinin
- Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah
| | - Marvin E. Tanenbaum
- Hubrecht Institute, The Royal Netherlands Academy of Arts and Sciences (KNAW) and University Medical Center, Utrecht, The Netherlands
| | - Jing Xu
- School of Natural Sciences, University of California, Merced, California
| | | | - Karim Arabi
- Department of Developmental and Cell Biology, University of California, Irvine, CA
| | - Dail Chapman
- Department of Developmental and Cell Biology, University of California, Irvine, CA
| | - Tory Doolin
- Department of Developmental and Cell Biology, University of California, Irvine, CA
| | | | - Steven P. Gross
- Department of Developmental and Cell Biology, University of California, Irvine, CA
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48
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Vahdati AR, Sprouffske K, Wagner A. Effect of Population Size and Mutation Rate on the Evolution of RNA Sequences on an Adaptive Landscape Determined by RNA Folding. Int J Biol Sci 2017; 13:1138-1151. [PMID: 29104505 PMCID: PMC5666329 DOI: 10.7150/ijbs.19436] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 07/05/2017] [Indexed: 02/04/2023] Open
Abstract
The dynamics of populations evolving on an adaptive landscape depends on multiple factors, including the structure of the landscape, the rate of mutations, and effective population size. Existing theoretical work often makes ad hoc and simplifying assumptions about landscape structure, whereas experimental work can vary important parameters only to a limited extent. We here overcome some of these limitations by simulating the adaptive evolution of RNA molecules, whose fitness is determined by the thermodynamics of RNA secondary structure folding. We study the influence of mutation rates and population sizes on final mean population fitness, on the substitution rates of mutations, and on population diversity. We show that evolutionary dynamics cannot be understood as a function of mutation rate µ, population size N, or population mutation rate Nµ alone. For example, at a given mutation rate, clonal interference prevents the fixation of beneficial mutations as population size increases, but larger populations still arrive at a higher mean fitness. In addition, at the highest population mutation rates we study, mean final fitness increases with population size, because small populations are driven to low fitness by the relatively higher incidence of mutations they experience. Our observations show that mutation rate and population size can interact in complex ways to influence the adaptive dynamics of a population on a biophysically motivated fitness landscape.
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Affiliation(s)
- Ali R Vahdati
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,The Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Kathleen Sprouffske
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,The Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Andreas Wagner
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,The Swiss Institute of Bioinformatics, Lausanne, Switzerland.,The Santa Fe Institute, Santa Fe, USA
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49
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White NA, Hoogstraten CG. Thermodynamics and kinetics of RNA tertiary structure formation in the junctionless hairpin ribozyme. Biophys Chem 2017; 228:62-68. [PMID: 28710920 PMCID: PMC5572644 DOI: 10.1016/j.bpc.2017.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/24/2017] [Accepted: 07/02/2017] [Indexed: 11/15/2022]
Abstract
The hairpin ribozyme consists of two RNA internal loops that interact to form the catalytically active structure. This docking transition is a rare example of intermolecular formation of RNA tertiary structure without coupling to helix annealing. We have used temperature-dependent surface plasmon resonance (SPR) to characterize the thermodynamics and kinetics of RNA tertiary structure formation for the junctionless form of the ribozyme, in which loops A and B reside on separate molecules. We find docking to be strongly enthalpy-driven and to be accompanied by substantial activation barriers for association and dissociation, consistent with the structural reorganization of both internal loops upon complex formation. Comparisons with the parallel analysis of a ribozyme variant carrying a 2'-O-methyl modification at the self-cleavage site and with published data in other systems reveal a surprising diversity of thermodynamic signatures, emphasizing the delicate balance of contributions to the free energy of formation of RNA tertiary structure.
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Affiliation(s)
- Neil A White
- Department of Biochemistry and Molecular Biology, 603 Wilson Road, Room 302D, Michigan State University, East Lansing, MI 48824, USA
| | - Charles G Hoogstraten
- Department of Biochemistry and Molecular Biology, 603 Wilson Road, Room 302D, Michigan State University, East Lansing, MI 48824, USA.
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50
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Schuabb C, Kumar N, Pataraia S, Marx D, Winter R. Pressure modulates the self-cleavage step of the hairpin ribozyme. Nat Commun 2017; 8:14661. [PMID: 28358002 PMCID: PMC5379106 DOI: 10.1038/ncomms14661] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 01/20/2017] [Indexed: 01/01/2023] Open
Abstract
The ability of certain RNAs, denoted as ribozymes, to not only store genetic information but also catalyse chemical reactions gave support to the RNA world hypothesis as a putative step in the development of early life on Earth. This, however, might have evolved under extreme environmental conditions, including the deep sea with pressures in the kbar regime. Here we study pressure-induced effects on the self-cleavage of hairpin ribozyme by following structural changes in real-time. Our results suggest that compression of the ribozyme leads to an accelerated transesterification reaction, being the self-cleavage step, although the overall process is retarded in the high-pressure regime. The results reveal that favourable interactions between the reaction site and neighbouring nucleobases are strengthened under pressure, resulting therefore in an accelerated self-cleavage step upon compression. These results suggest that properly engineered ribozymes may also act as piezophilic biocatalysts in addition to their hitherto known properties.
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Affiliation(s)
- Caroline Schuabb
- Physikalische Chemie I-Biophysikalische Chemie, Fakultät für Chemie und Chemische Biologie, TU Dortmund, Otto-Hahn-Strasse 4a, Dortmund 44227, Germany
| | - Narendra Kumar
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, Bochum 44780, Germany
| | - Salome Pataraia
- Physikalische Chemie I-Biophysikalische Chemie, Fakultät für Chemie und Chemische Biologie, TU Dortmund, Otto-Hahn-Strasse 4a, Dortmund 44227, Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, Bochum 44780, Germany
| | - Roland Winter
- Physikalische Chemie I-Biophysikalische Chemie, Fakultät für Chemie und Chemische Biologie, TU Dortmund, Otto-Hahn-Strasse 4a, Dortmund 44227, Germany
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