1
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Tužinčin D, Padrta P, Šanderová H, Rabatinová A, Bendová K, Krásný L, Žídek L, Kadeřávek P. Characterization of a transitionally occupied state and thermal unfolding of domain 1.1 of σ A factor of RNA polymerase from Bacillus subtilis. Proteins 2023; 91:1276-1287. [PMID: 37350110 DOI: 10.1002/prot.26531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 05/06/2023] [Accepted: 05/10/2023] [Indexed: 06/24/2023]
Abstract
σ factors are essential parts of bacterial RNA polymerase (RNAP) as they allow to recognize promotor sequences and initiate transcription. Domain 1.1 of vegetative σ factors occupies the primary channel of RNAP and also prevents binding of the σ factor to promoter DNA alone. Here, we show that domain 1.1 of Bacillus subtilisσ A exists in more structurally distinct variants in dynamic equilibrium. The major conformation at room temperature is represented by a previously reported well-folded structure solved by nuclear magnetic resonance (NMR), but 4% of the protein molecules are present in a less thermodynamically favorable state. We show that this population increases with temperature and we predict its significant elevation at higher but still biologically relevant temperatures. We characterized the minor state of the domain 1.1 using specialized methods of NMR. We found that, in contrast to the major state, the detected minor state is partially unfolded. Its propensity to form secondary structure elements is especially decreased for the first and third α helices, while the second α helix and β strand close to the C-terminus are more stable. We also analyzed thermal unfolding of the domain 1.1 and performed functional experiments with full lengthσ A and its shortened version lacking domain 1.1 (σ A _ Δ 1.1 ). The results revealed that while full lengthσ A increases transcription activity of RNAP with increasing temperature, transcription withσ A _ Δ 1.1 remains constant. In summary, this study reveals conformational dynamics of domain 1.1 and provides a basis for studies of its interaction with RNAP and effects on transcription regulation.
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Affiliation(s)
- Dávid Tužinčin
- National Centre for Biomolecular Research (NCBR), Faculty of Science, Masaryk University, Brno, Czech Republic
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Petr Padrta
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Hana Šanderová
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Alžběta Rabatinová
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Kateřina Bendová
- National Centre for Biomolecular Research (NCBR), Faculty of Science, Masaryk University, Brno, Czech Republic
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Libor Krásný
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Lukáš Žídek
- National Centre for Biomolecular Research (NCBR), Faculty of Science, Masaryk University, Brno, Czech Republic
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Pavel Kadeřávek
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
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2
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Krishnarjuna B, Ravula T, Faison EM, Tonelli M, Zhang Q, Ramamoorthy A. Polymer-Nanodiscs as a Novel Alignment Medium for High-Resolution NMR-Based Structural Studies of Nucleic Acids. Biomolecules 2022; 12:1628. [PMID: 36358983 PMCID: PMC9687133 DOI: 10.3390/biom12111628] [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: 09/29/2022] [Revised: 10/28/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022] Open
Abstract
Residual dipolar couplings (RDCs) are increasingly used for high-throughput NMR-based structural studies and to provide long-range angular constraints to validate and refine structures of various molecules determined by X-ray crystallography and NMR spectroscopy. RDCs of a given molecule can be measured in an anisotropic environment that aligns in an external magnetic field. Here, we demonstrate the first application of polymer-based nanodiscs for the measurement of RDCs from nucleic acids. Polymer-based nanodiscs prepared using negatively charged SMA-EA polymer and zwitterionic DMPC lipids were characterized by size-exclusion chromatography, 1H NMR, dynamic light-scattering, and 2H NMR. The magnetically aligned polymer-nanodiscs were used as an alignment medium to measure RDCs from a 13C/15N-labeled fluoride riboswitch aptamer using 2D ARTSY-HSQC NMR experiments. The results showed that the alignment of nanodiscs is stable for nucleic acids and nanodisc-induced RDCs fit well with the previously determined solution structure of the riboswitch. These results demonstrate that SMA-EA-based lipid-nanodiscs can be used as a stable alignment medium for high-resolution structural and dynamical studies of nucleic acids, and they can also be applicable to study various other biomolecules and small molecules in general.
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Affiliation(s)
- Bankala Krishnarjuna
- Biophysics Program, Department of Chemistry, Biomedical Engineering, and Macromolecular Science and Engineering, Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Thirupathi Ravula
- Biophysics Program, Department of Chemistry, Biomedical Engineering, and Macromolecular Science and Engineering, Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA
- National Magnetic Resonance Facility at Madison, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Edgar M. Faison
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Marco Tonelli
- National Magnetic Resonance Facility at Madison, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Qi Zhang
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics Program, Department of Chemistry, Biomedical Engineering, and Macromolecular Science and Engineering, Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA
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3
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Chiliveri SC, Robertson AJ, Shen Y, Torchia DA, Bax A. Advances in NMR Spectroscopy of Weakly Aligned Biomolecular Systems. Chem Rev 2021; 122:9307-9330. [PMID: 34766756 DOI: 10.1021/acs.chemrev.1c00730] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The measurement and application of residual dipolar couplings (RDCs) in solution NMR studies of biological macromolecules has become well established over the past quarter of a century. Numerous methods for generating the requisite anisotropic orientational molecular distribution have been demonstrated, each with its specific strengths and weaknesses. In parallel, an enormous number of pulse schemes have been introduced to measure the many different types of RDCs, ranging from the most widely measured backbone amide 15N-1H RDCs, to 1H-1H RDCs and couplings between low-γ nuclei. Applications of RDCs range from structure validation and refinement to the determination of relative domain orientations, the measurement of backbone and domain motions, and de novo structure determination. Nevertheless, it appears that the power of the RDC methodology remains underutilized. This review aims to highlight the practical aspects of sample preparation and RDC measurement while describing some of the most straightforward applications that take advantage of the exceptionally precise information contained in such data. Some emphasis will be placed on more recent developments that enable the accurate measurement of RDCs in larger systems, which is key to the ongoing shift in focus of biological NMR spectroscopy from structure determination toward gaining improved understanding of how molecular flexibility drives protein function.
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Affiliation(s)
- Sai Chaitanya Chiliveri
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Angus J Robertson
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Yang Shen
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Dennis A Torchia
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
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4
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Advanced approaches for elucidating structures of large RNAs using NMR spectroscopy and complementary methods. Methods 2020; 183:93-107. [DOI: 10.1016/j.ymeth.2020.01.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 11/11/2019] [Accepted: 01/16/2020] [Indexed: 11/23/2022] Open
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5
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Refining RNA solution structures with the integrative use of label-free paramagnetic relaxation enhancement NMR. BIOPHYSICS REPORTS 2019. [DOI: 10.1007/s41048-019-00099-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
AbstractNMR structure calculation is inherently integrative, and can incorporate new experimental data as restraints. As RNAs have lower proton densities and are more conformational heterogenous than proteins, the refinement of RNA structures can benefit from additional types of restraints. Paramagnetic relaxation enhancement (PRE) provides distance information between a paramagnetic probe and protein or RNA nuclei. However, covalent conjugation of a paramagnetic probe is difficult for RNAs, thus limiting the use of PRE NMR for RNA structure characterization. Here, we show that the solvent PRE can be accurately measured for RNA labile imino protons, simply with the addition of an inert paramagnetic cosolute. Demonstrated on three RNAs that have increasingly complex topologies, we show that the incorporation of the solvent PRE restraints can significantly improve the precision and accuracy of RNA structures. Importantly, the solvent PRE data can be collected for RNAs without isotope enrichment. Thus, the solvent PRE method can work integratively with other biophysical techniques for better characterization of RNA structures.
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6
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Loth K, Largillière J, Coste F, Culard F, Landon C, Castaing B, Delmas AF, Paquet F. New protein-DNA complexes in archaea: a small monomeric protein induces a sharp V-turn DNA structure. Sci Rep 2019; 9:14253. [PMID: 31582767 PMCID: PMC6776556 DOI: 10.1038/s41598-019-50211-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 09/05/2019] [Indexed: 01/02/2023] Open
Abstract
MC1, a monomeric nucleoid-associated protein (NAP), is structurally unrelated to other DNA-binding proteins. The protein participates in the genome organization of several Euryarchaea species through an atypical compaction mechanism. It is also involved in DNA transcription and cellular division through unknown mechanisms. We determined the 3D solution structure of a new DNA-protein complex formed by MC1 and a strongly distorted 15 base pairs DNA. While the protein just needs to adapt its conformation slightly, the DNA undergoes a dramatic curvature (the first two bend angles of 55° and 70°, respectively) and an impressive torsional stress (dihedral angle of 106°) due to several kinks upon binding of MC1 to its concave side. Thus, it adopts a V-turn structure. For longer DNAs, MC1 stabilizes multiple V-turn conformations in a flexible and dynamic manner. The existence of such V-turn conformations of the MC1-DNA complexes leads us to propose two binding modes of the protein, as a bender (primary binding mode) and as a wrapper (secondary binding mode). Moreover, it opens up new opportunities for studying and understanding the repair, replication and transcription molecular machineries of Archaea.
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Affiliation(s)
- Karine Loth
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France. .,UFR Collegium Sciences et Techniques, Université d'Orléans, rue de Chartres, 45100, Orléans, France.
| | - Justine Largillière
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France
| | - Franck Coste
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France
| | - Françoise Culard
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France
| | - Céline Landon
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France
| | - Bertrand Castaing
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France
| | - Agnès F Delmas
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France
| | - Françoise Paquet
- Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, rue Charles Sadron, F-45071, Orléans, Cedex 2, France.
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7
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Probing the dynamic stalk region of the ribosome using solution NMR. Sci Rep 2019; 9:13528. [PMID: 31537834 PMCID: PMC6753160 DOI: 10.1038/s41598-019-49190-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/31/2019] [Indexed: 11/29/2022] Open
Abstract
We describe an NMR approach based on the measurement of residual dipolar couplings (RDCs) to probe the structural and motional properties of the dynamic regions of the ribosome. Alignment of intact 70S ribosomes in filamentous bacteriophage enabled measurement of RDCs in the mobile C-terminal domain (CTD) of the stalk protein bL12. A structural refinement of this domain using the observed RDCs did not show large changes relative to the isolated protein in the absence of the ribosome, and we also found that alignment of the CTD was almost independent of the presence of the core ribosome particle, indicating that the inter-domain linker has significant flexibility. The nature of this linker was subsequently probed in more detail using a paramagnetic alignment strategy, which revealed partial propagation of alignment between neighbouring domains, providing direct experimental validation of a structural ensemble previously derived from SAXS and NMR relaxation measurements. Our results demonstrate the prospect of better characterising dynamical and functional regions of more challenging macromolecular machines and systems, for example ribosome–nascent chain complexes.
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8
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Cerofolini L, Giuntini S, Carlon A, Ravera E, Calderone V, Fragai M, Parigi G, Luchinat C. Characterization of PEGylated Asparaginase: New Opportunities from NMR Analysis of Large PEGylated Therapeutics. Chemistry 2019; 25:1984-1991. [DOI: 10.1002/chem.201804488] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/09/2018] [Indexed: 11/12/2022]
Affiliation(s)
- Linda Cerofolini
- Magnetic Resonance Center (CERM)University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di, Metallo Proteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
| | - Stefano Giuntini
- Magnetic Resonance Center (CERM)University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di, Metallo Proteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of ChemistryUniversity of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Azzurra Carlon
- Magnetic Resonance Center (CERM)University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di, Metallo Proteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
| | - Enrico Ravera
- Magnetic Resonance Center (CERM)University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di, Metallo Proteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of ChemistryUniversity of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Vito Calderone
- Magnetic Resonance Center (CERM)University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di, Metallo Proteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of ChemistryUniversity of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Marco Fragai
- Magnetic Resonance Center (CERM)University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di, Metallo Proteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of ChemistryUniversity of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM)University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di, Metallo Proteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of ChemistryUniversity of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM)University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di, Metallo Proteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of ChemistryUniversity of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
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9
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Applications of NMR to structure determination of RNAs large and small. Arch Biochem Biophys 2017; 628:42-56. [PMID: 28600200 DOI: 10.1016/j.abb.2017.06.003] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 05/31/2017] [Accepted: 06/04/2017] [Indexed: 02/07/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool to investigate the structure and dynamics of RNA, because many biologically important RNAs have conformationally flexible structures, which makes them difficult to crystallize. Functional, independently folded RNA domains, range in size between simple stem-loops of as few as 10-20 nucleotides, to 50-70 nucleotides, the size of tRNA and many small ribozymes, to a few hundred nucleotides, the size of more complex RNA enzymes and of the functional domains of non-coding transcripts. In this review, we discuss new methods for sample preparation, assignment strategies and structure determination for independently folded RNA domains of up to 100 kDa in molecular weight.
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10
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Venditti V, Egner TK, Clore GM. Hybrid Approaches to Structural Characterization of Conformational Ensembles of Complex Macromolecular Systems Combining NMR Residual Dipolar Couplings and Solution X-ray Scattering. Chem Rev 2016; 116:6305-22. [PMID: 26739383 PMCID: PMC5590664 DOI: 10.1021/acs.chemrev.5b00592] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Solving structures or structural ensembles of large macromolecular systems in solution poses a challenging problem. While NMR provides structural information at atomic resolution, increased spectral complexity, chemical shift overlap, and short transverse relaxation times (associated with slow tumbling) render application of the usual techniques that have been so successful for medium sized systems (<50 kDa) difficult. Solution X-ray scattering, on the other hand, is not limited by molecular weight but only provides low resolution structural information related to the overall shape and size of the system under investigation. Here we review how combining atomic resolution structures of smaller domains with sparse experimental data afforded by NMR residual dipolar couplings (which yield both orientational and shape information) and solution X-ray scattering data in rigid-body simulated annealing calculations provides a powerful approach for investigating the structural aspects of conformational dynamics in large multidomain proteins. The application of this hybrid methodology is illustrated for the 128 kDa dimer of bacterial Enzyme I which exists in a variety of open and closed states that are sampled at various points in the catalytic cycles, and for the capsid protein of the human immunodeficiency virus.
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Affiliation(s)
- Vincenzo Venditti
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Timothy K. Egner
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - G. Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
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11
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Imeddourene AB, Xu X, Zargarian L, Oguey C, Foloppe N, Mauffret O, Hartmann B. The intrinsic mechanics of B-DNA in solution characterized by NMR. Nucleic Acids Res 2016; 44:3432-47. [PMID: 26883628 PMCID: PMC4838374 DOI: 10.1093/nar/gkw084] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 02/01/2016] [Indexed: 12/19/2022] Open
Abstract
Experimental characterization of the structural couplings in free B-DNA in solution has been elusive, because of subtle effects that are challenging to tackle. Here, the exploitation of the NMR measurements collected on four dodecamers containing a substantial set of dinucleotide sequences provides new, consistent correlations revealing the DNA intrinsic mechanics. The difference between two successive residual dipolar couplings (ΔRDCs) involving C6/8-H6/8, C3′-H3′ and C4′-H4′ vectors are correlated to the 31P chemical shifts (δP), which reflect the populations of the BI and BII backbone states. The δPs are also correlated to the internucleotide distances (Dinter) involving H6/8, H2′ and H2″ protons. Calculations of NMR quantities on high resolution X-ray structures and controlled models of DNA enable to interpret these couplings: the studied ΔRDCs depend mostly on roll, while Dinter are mainly sensitive to twist or slide. Overall, these relations demonstrate how δP measurements inform on key inter base parameters, in addition to probe the BI↔BII backbone equilibrium, and shed new light into coordinated motions of phosphate groups and bases in free B-DNA in solution. Inspection of the 5′ and 3′ ends of the dodecamers also supplies new information on the fraying events, otherwise neglected.
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Affiliation(s)
- Akli Ben Imeddourene
- Laboratoire de Biologie et Pharmacologie Appliquée, ENS Cachan, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan cedex, France Université Pierre et Marie Curie, 4 Place Jussieu, 75005 Paris, France
| | - Xiaoqian Xu
- Laboratoire de Biologie et Pharmacologie Appliquée, ENS Cachan, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan cedex, France Department of Life Sciences, East China Normal University, 200062 Shanghai, People's Republic of China
| | - Loussiné Zargarian
- Laboratoire de Biologie et Pharmacologie Appliquée, ENS Cachan, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan cedex, France
| | - Christophe Oguey
- Laboratoire de Physique Théorique et Modélisation, UMR 8089, CNRS, Université de Cergy-Pontoise, Cergy-Pontoise, France
| | | | - Olivier Mauffret
- Laboratoire de Biologie et Pharmacologie Appliquée, ENS Cachan, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan cedex, France
| | - Brigitte Hartmann
- Laboratoire de Biologie et Pharmacologie Appliquée, ENS Cachan, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan cedex, France
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12
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Newby FN, De Simone A, Yagi-Utsumi M, Salvatella X, Dobson CM, Vendruscolo M. Structure-Free Validation of Residual Dipolar Coupling and Paramagnetic Relaxation Enhancement Measurements of Disordered Proteins. Biochemistry 2015; 54:6876-86. [DOI: 10.1021/acs.biochem.5b00670] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Francisco N. Newby
- Department
of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Alfonso De Simone
- Department
of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, U.K
| | - Maho Yagi-Utsumi
- Department
of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
- Institute
for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama Myodaiji, Okazaki 444-8787, Japan
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13
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Scott LG, Hennig M. ¹⁹F-Site-Specific-Labeled Nucleotides for Nucleic Acid Structural Analysis by NMR. Methods Enzymol 2015; 566:59-87. [PMID: 26791976 DOI: 10.1016/bs.mie.2015.05.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Naturally occurring RNA lacks fluorine-19 ((19)F), thus, their specifically fluorinated counterparts are particularly well suited to noninvasively monitoring the dynamic conformational properties and ligand-binding interactions of the RNA. For nuclear magnetic resonance (NMR) spectroscopy, (19)F-NMR of fluorine-substituted RNA provides an attractive, site-specific probe for structure determination in solution. Advantages of (19)F include high NMR sensitivity (83% of (1)H), high natural abundance (100%), and the extreme sensitivity of (19)F to the chemical environment leading to a large range of chemical shifts. The preparation of base-substituted 2-fluoropurine and 5-fluoropyrimidine 5'-triphosphates (2F-ATP/5F-CTP/5F-UTP) can be carried out using efficient enzymatic synthesis methods. Both pyrimidine analogs, 5-fluorouridine and 5-fluorocytidine, as well as, 2-fluoroadenosine are readily incorporated into RNA transcribed in vitro using T7 RNA polymerase.
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Affiliation(s)
| | - Mirko Hennig
- Nutrition Research Institute, University of North Carolina at Chapel Hill, Kannapolis, North Carolina, USA.
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14
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Cerofolini L, Amato J, Giachetti A, Limongelli V, Novellino E, Parrinello M, Fragai M, Randazzo A, Luchinat C. G-triplex structure and formation propensity. Nucleic Acids Res 2014; 42:13393-404. [PMID: 25378342 PMCID: PMC4245950 DOI: 10.1093/nar/gku1084] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 10/15/2014] [Accepted: 10/17/2014] [Indexed: 12/17/2022] Open
Abstract
The occurrence of a G-triplex folding intermediate of thrombin binding aptamer (TBA) has been recently predicted by metadynamics calculations, and experimentally supported by Nuclear Magnetic Resonance (NMR), Circular Dichroism (CD) and Differential Scanning Calorimetry (DSC) data collected on a 3' end TBA-truncated 11-mer oligonucleotide (11-mer-3'-t-TBA). Here we present the solution structure of 11-mer-3'-t-TBA in the presence of potassium ions. This structure is the first experimental example of a G-triplex folding, where a network of Hoogsteen-like hydrogen bonds stabilizes six guanines to form two G:G:G triad planes. The G-triplex folding of 11-mer-3'-t-TBA is stabilized by the potassium ion and destabilized by increasing the temperature. The superimposition of the experimental structure with that predicted by metadynamics shows a great similarity, with only significant differences involving two loops. These new structural data show that 11-mer-3'-t-TBA assumes a G-triplex DNA conformation as its stable form, reinforcing the idea that G-triplex folding intermediates may occur in vivo in human guanine-rich sequences. NMR and CD screening of eight different constructs obtained by removing from one to four bases at either the 3' and the 5' ends show that only the 11-mer-3'-t-TBA yields a relatively stable G-triplex.
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Affiliation(s)
- Linda Cerofolini
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino, Florence 50019, Italy Giotto Biotech, Via Madonna del Piano 6, Sesto Fiorentino, Florence 50019, Italy
| | - Jussara Amato
- Department of Pharmacy, University of Naples 'Federico II', Naples I-80131, Italy
| | - Andrea Giachetti
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino, Florence 50019, Italy
| | - Vittorio Limongelli
- Department of Pharmacy, University of Naples 'Federico II', Naples I-80131, Italy
| | - Ettore Novellino
- Department of Pharmacy, University of Naples 'Federico II', Naples I-80131, Italy
| | - Michele Parrinello
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich CH-8006, Swizerland Facoltà di Informatica, Istituto di Scienze Computazionali (ICS), Università della Svizzera Italiana, Lugano CH-6900, Switzerland
| | - Marco Fragai
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino, Florence 50019, Italy Department of Chemistry, University of Florence, Sesto Fiorentino, Florence 50019, Italy
| | - Antonio Randazzo
- Department of Pharmacy, University of Naples 'Federico II', Naples I-80131, Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino, Florence 50019, Italy Department of Chemistry, University of Florence, Sesto Fiorentino, Florence 50019, Italy
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15
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Walavalkar NM, Cramer JM, Buchwald WA, Scarsdale JN, Williams DC. Solution structure and intramolecular exchange of methyl-cytosine binding domain protein 4 (MBD4) on DNA suggests a mechanism to scan for mCpG/TpG mismatches. Nucleic Acids Res 2014; 42:11218-32. [PMID: 25183517 PMCID: PMC4176167 DOI: 10.1093/nar/gku782] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Unlike other members of the methyl-cytosine binding domain (MBD) family, MBD4 serves as a potent DNA glycosylase in DNA mismatch repair specifically targeting mCpG/TpG mismatches arising from spontaneous deamination of methyl-cytosine. The protein contains an N-terminal MBD (MBD4MBD) and a C-terminal glycosylase domain (MBD4GD) separated by a long linker. This arrangement suggests that the MBD4MBD either directly augments enzymatic catalysis by the MBD4GD or targets the protein to regions enriched for mCpG/TpG mismatches. Here we present structural and dynamic studies of MBD4MBD bound to dsDNA. We show that MBD4MBD binds with a modest preference formCpG as compared to mismatch, unmethylated and hydroxymethylated DNA. We find that while MBD4MBD exhibits slow exchange between molecules of DNA (intermolecular exchange), the domain exhibits fast exchange between two sites in the same molecule of dsDNA (intramolecular exchange). Introducing a single-strand defect between binding sites does not greatly reduce the intramolecular exchange rate, consistent with a local hopping mechanism for moving along the DNA. These results support a model in which the MBD4MBD4 targets the intact protein to mCpG islands and promotes scanning by rapidly exchanging between successive mCpG sites which facilitates repair of nearby mCpG/TpG mismatches by the glycosylase domain.
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Affiliation(s)
- Ninad M Walavalkar
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jason M Cramer
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - William A Buchwald
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - J Neel Scarsdale
- Institute of Structural Biology and Drug Discovery, Center for the Study of Biological Complexity and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - David C Williams
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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16
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Göbl C, Madl T, Simon B, Sattler M. NMR approaches for structural analysis of multidomain proteins and complexes in solution. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 80:26-63. [PMID: 24924266 DOI: 10.1016/j.pnmrs.2014.05.003] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 05/14/2014] [Indexed: 05/22/2023]
Abstract
NMR spectroscopy is a key method for studying the structure and dynamics of (large) multidomain proteins and complexes in solution. It plays a unique role in integrated structural biology approaches as especially information about conformational dynamics can be readily obtained at residue resolution. Here, we review NMR techniques for such studies focusing on state-of-the-art tools and practical aspects. An efficient approach for determining the quaternary structure of multidomain complexes starts from the structures of individual domains or subunits. The arrangement of the domains/subunits within the complex is then defined based on NMR measurements that provide information about the domain interfaces combined with (long-range) distance and orientational restraints. Aspects discussed include sample preparation, specific isotope labeling and spin labeling; determination of binding interfaces and domain/subunit arrangements from chemical shift perturbations (CSP), nuclear Overhauser effects (NOEs), isotope editing/filtering, cross-saturation, and differential line broadening; and based on paramagnetic relaxation enhancements (PRE) using covalent and soluble spin labels. Finally, the utility of complementary methods such as small-angle X-ray or neutron scattering (SAXS, SANS), electron paramagnetic resonance (EPR) or fluorescence spectroscopy techniques is discussed. The applications of NMR techniques are illustrated with studies of challenging (high molecular weight) protein complexes.
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Affiliation(s)
- Christoph Göbl
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technische Universität München, Garching, Germany
| | - Tobias Madl
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technische Universität München, Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany; Institute of Molecular Biology, University of Graz, Graz, Austria.
| | - Bernd Simon
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Michael Sattler
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technische Universität München, Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany.
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17
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Kruschel D, Skilandat M, Sigel RK. NMR structure of the 5' splice site in the group IIB intron Sc.ai5γ--conformational requirements for exon-intron recognition. RNA (NEW YORK, N.Y.) 2014; 20:295-307. [PMID: 24448450 PMCID: PMC3923125 DOI: 10.1261/rna.041137.113] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A crucial step of the self-splicing reaction of group II intron ribozymes is the recognition of the 5' exon by the intron. This recognition is achieved by two regions in domain 1 of the intron, the exon-binding sites EBS1 and EBS2 forming base pairs with the intron-binding sites IBS1 and IBS2 located at the end of the 5' exon. The complementarity of the EBS1•IBS1 contact is most important for ensuring site-specific cleavage of the phosphodiester bond between the 5' exon and the intron. Here, we present the NMR solution structures of the d3' hairpin including EBS1 free in solution and bound to the IBS1 7-mer. In the unbound state, EBS1 is part of a flexible 11-nucleotide (nt) loop. Binding of IBS1 restructures and freezes the entire loop region. Mg(2+) ions are bound near the termini of the EBS1•IBS1 helix, stabilizing the interaction. Formation of the 7-bp EBS1•IBS1 helix within a loop of only 11 nt forces the loop backbone to form a sharp turn opposite of the splice site, thereby presenting the scissile phosphate in a position that is structurally unique.
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18
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Twomey EC, Cordasco DF, Kozuch SD, Wei Y. Substantial conformational change mediated by charge-triad residues of the death effector domain in protein-protein interactions. PLoS One 2013; 8:e83421. [PMID: 24391764 PMCID: PMC3877032 DOI: 10.1371/journal.pone.0083421] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 11/03/2013] [Indexed: 11/18/2022] Open
Abstract
Protein conformational changes are commonly associated with the formation of protein complexes. The non-catalytic death effector domains (DEDs) mediate protein-protein interactions in a variety of cellular processes, including apoptosis, proliferation and migration, and glucose metabolism. Here, using NMR residual dipolar coupling (RDC) data, we report a conformational change in the DED of the phosphoprotein enriched in astrocytes, 15 kDa (PEA-15) protein in the complex with a mitogen-activated protein (MAP) kinase, extracellular regulated kinase 2 (ERK2), which is essential in regulating ERK2 cellular distribution and function in cell proliferation and migration. The most significant conformational change in PEA-15 happens at helices α2, α3, and α4, which also possess the highest flexibility among the six-helix bundle of the DED. This crucial conformational change is modulated by the D/E-RxDL charge-triad motif, one of the prominent structural features of DEDs, together with a number of other electrostatic and hydrogen bonding interactions on the protein surface. Charge-triad motif promotes the optimal orientation of key residues and expands the binding interface to accommodate protein-protein interactions. However, the charge-triad residues are not directly involved in the binding interface between PEA-15 and ERK2.
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Affiliation(s)
- Edward C. Twomey
- Institute of NeuroImmune Pharmacology, Seton Hall University, South Orange, New Jersey, United States of America
- Department of Chemistry and Biochemistry, Seton Hall University, South Orange, New Jersey, United States of America
- Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University, New York, New York, United States of America
| | - Dana F. Cordasco
- Institute of NeuroImmune Pharmacology, Seton Hall University, South Orange, New Jersey, United States of America
- Department of Chemistry and Biochemistry, Seton Hall University, South Orange, New Jersey, United States of America
| | - Stephen D. Kozuch
- Department of Chemistry and Biochemistry, Seton Hall University, South Orange, New Jersey, United States of America
| | - Yufeng Wei
- Institute of NeuroImmune Pharmacology, Seton Hall University, South Orange, New Jersey, United States of America
- * E-mail:
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19
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Twomey EC, Wei Y. High-definition NMR structure of PED/PEA-15 death effector domain reveals details of key polar side chain interactions. Biochem Biophys Res Commun 2012; 424:141-6. [PMID: 22732408 DOI: 10.1016/j.bbrc.2012.06.091] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 06/16/2012] [Indexed: 11/17/2022]
Abstract
Death effector domain (DED) proteins constitute a subfamily of the large death domain superfamily that is primarily involved in apoptosis pathways. DED structures have characteristic side chain-side chain interactions among polar residues on the protein surface, forming a network of hydrogen bonds and salt bridges. The polar interaction network is functionally important in promoting protein-protein interactions by maintaining optimal side chain orientations. We have refined the solution DED structure of the PED/PEA-15 protein, a representative member of DED subfamily, using traditional NMR restraints with the addition of residual dipolar coupling (RDC) restraints from two independent alignment media, and employed the explicit solvent refinement protocol. The newly refined DED structure of PED/PEA-15 possesses higher structural quality as indicated by WHAT IF Z-scores, with most significant improvement in the backbone conformation normality quality factor. This higher quality DED structure of PED/PEA-15 leads to the identification of a number of key polar side chain interactions, which are not typically observed in NMR protein structures. The elucidation of polar side chain interactions is a key step towards the understanding of protein-protein interactions involving the death domain superfamily. The NMR structures with extensive details of protein structural features are thereby termed high-definition (HD) NMR structures.
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Affiliation(s)
- Edward C Twomey
- Department of Chemistry and Biochemistry, Seton Hall University, South Orange, NJ 07094-2646, USA
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20
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Eichhorn CD, Feng J, Suddala KC, Walter NG, Brooks CL, Al-Hashimi HM. Unraveling the structural complexity in a single-stranded RNA tail: implications for efficient ligand binding in the prequeuosine riboswitch. Nucleic Acids Res 2011; 40:1345-55. [PMID: 22009676 PMCID: PMC3273816 DOI: 10.1093/nar/gkr833] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Single-stranded RNAs (ssRNAs) are ubiquitous RNA elements that serve diverse functional roles. Much of our understanding of ssRNA conformational behavior is limited to structures in which ssRNA directly engages in tertiary interactions or is recognized by proteins. Little is known about the structural and dynamic behavior of free ssRNAs at atomic resolution. Here, we report the collaborative application of nuclear magnetic resonance (NMR) and replica exchange molecular dynamics (REMD) simulations to characterize the 12 nt ssRNA tail derived from the prequeuosine riboswitch. NMR carbon spin relaxation data and residual dipolar coupling measurements reveal a flexible yet stacked core adopting an A-form-like conformation, with the level of order decreasing toward the terminal ends. An A-to-C mutation within the polyadenine tract alters the observed dynamics consistent with the introduction of a dynamic kink. Pre-ordering of the tail may increase the efficacy of ligand binding above that achieved by a random-coil ssRNA. The REMD simulations recapitulate important trends in the NMR data, but suggest more internal motions than inferred from the NMR analysis. Our study unmasks a previously unappreciated level of complexity in ssRNA, which we believe will also serve as an excellent model system for testing and developing computational force fields.
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Affiliation(s)
- Catherine D Eichhorn
- Chemical Biology Doctoral Program, University of Michigan, Ann Arbor, MI 48109, USA
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21
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Dominguez C, Schubert M, Duss O, Ravindranathan S, Allain FHT. Structure determination and dynamics of protein-RNA complexes by NMR spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2011; 58:1-61. [PMID: 21241883 DOI: 10.1016/j.pnmrs.2010.10.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Accepted: 04/24/2010] [Indexed: 05/30/2023]
Affiliation(s)
- Cyril Dominguez
- Institute for Molecular Biology and Biophysics, ETH Zürich, CH-8093 Zürich, Switzerland
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22
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Park SH, Opella SJ. Triton X-100 as the "short-chain lipid" improves the magnetic alignment and stability of membrane proteins in phosphatidylcholine bilayers for oriented-sample solid-state NMR spectroscopy. J Am Chem Soc 2011; 132:12552-3. [PMID: 20735058 DOI: 10.1021/ja1055565] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A mixture of phospholipids and Triton X-100 in a molar ratio of 5:1 forms well-aligned and stable bilayers that give superior solid-state NMR spectra of proteins. In a comparison, the oriented-sample (OS) solid-state NMR spectrum of Pf1 coat protein in aligned phospholipid bilayers displayed better resolution than the equivalent solution NMR spectrum of the same protein in micelles. Both samples and experimental parameters were fully optimized.
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Affiliation(s)
- Sang Ho Park
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0307, USA
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23
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A'-form RNA helices are required for cytoplasmic mRNA transport in Drosophila. Nat Struct Mol Biol 2010; 17:703-9. [PMID: 20473315 PMCID: PMC2997434 DOI: 10.1038/nsmb.1813] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 03/22/2010] [Indexed: 01/05/2023]
Abstract
Microtubule-based mRNA transport is widely used to restrict protein expression to specific regions in the cell, and has important roles in defining cell polarity, axis determination and for neuronal function. However, the structural basis of recognition of cis-acting mRNA localization signals by motor complexes is poorly understood. We have used NMR spectroscopy to describe the first tertiary structure of an RNA element responsible for mRNA transport. The Drosophila fs(1)K10 signal, which mediates transport by the dynein motor, forms a stem-loop with two double-stranded RNA helices adopting an unusual A′-form conformation with widened, major grooves reminiscent of those in B-form DNA. Structure determination of four mutant RNAs and extensive functional assays in Drosophila embryos indicate that the two spatially registered A′-form helices represent critical recognition sites for the transport machinery. Our study provides important insights into the basis for RNA cargo recognition and reveals a key biological function encoded by A′-form RNA conformation.
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24
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Simon B, Madl T, Mackereth C, Nilges M, Sattler M. An Efficient Protocol for NMR-Spectroscopy-Based Structure Determination of Protein Complexes in Solution. Angew Chem Int Ed Engl 2010; 49:1967-70. [DOI: 10.1002/anie.200906147] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Simon B, Madl T, Mackereth C, Nilges M, Sattler M. An Efficient Protocol for NMR-Spectroscopy-Based Structure Determination of Protein Complexes in Solution. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.200906147] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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26
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Dethoff EA, Hansen AL, Zhang Q, Al-Hashimi HM. Variable helix elongation as a tool to modulate RNA alignment and motional couplings. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 202:117-21. [PMID: 19854083 PMCID: PMC3319148 DOI: 10.1016/j.jmr.2009.09.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 09/23/2009] [Accepted: 09/26/2009] [Indexed: 05/13/2023]
Abstract
The application of residual dipolar couplings (RDCs) in studies of RNA structure and dynamics can be complicated by the presence of couplings between collective helix motions and overall alignment and by the inability to modulate overall alignment of the molecule by changing the ordering medium. Here, we show for a 27-nt TAR RNA construct that variable levels of helix elongation can be used to alter both overall alignment and couplings to collective helix motions in a semi-predictable manner. In the absence of elongation, a four base-pair helix II capped by a UUCG apical loop exhibits a higher degree of order compared to a six base-pair helix I (theta(I)/theta(II)=0.56+/-0.1). The principal S(zz) direction is nearly parallel to the axis of helix II but deviates by approximately 40 degrees relative to the axis of helix I. Elongating helix I by three base-pairs equalizes the alignment of the two helices and pushes the RNA into the motional coupling limit such that the two helices have comparable degrees of order (theta(I)/theta(II)=0.92+/-0.04) and orientations relative to S(zz) ( approximately 17 degrees ). Increasing the length of elongation further to 22 base-pairs pushes the RNA into the motional decoupling limit in which helix I dominates alignment (theta(II)/theta(I)=0.45+/-0.05), with S(zz) orientated nearly parallel to its helix axis. Many of these trends can be rationalized using PALES simulations that employ a previously proposed three-state dynamic ensemble of TAR. Our results provide new insights into motional couplings, offer guidelines for assessing their extent, and suggest that variable degrees of helix elongation can allow access to independent sets of RDCs for characterizing RNA structural dynamics.
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Affiliation(s)
- Elizabeth A. Dethoff
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alexandar L. Hansen
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
- Departments of Molecular Genetics, Biochemistry, and Chemistry, University of Toronto, Toronto, Ontario, Canada, M5S 1A8
| | - Qi Zhang
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Hashim M. Al-Hashimi
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
- To whom correspondence should be addressed. H. M. A.: ; telephone (734) 615 3361; fax (734) 647 4865
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27
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Abstract
The use of contemporary nuclear magnetic resonance (NMR) methods in the studies of model systems between microRNA (miRNA) and messenger RNA (mRNA) is reviewed. We describe our studies on structural features of 33-nt RNA model construct between let-7 miRNA and lin-41 mRNA at the second binding site. let-7 miRNA inhibits translation of lin-41 gene through formation of two complexes with the target sequence within 3' untranslated region of lin-41 mRNA in Caenorhabditis elegans. The base pairing, asymmetric internal loops, and adenine bulge in both the complementary sites are important for regulation of gene expression. NMR study on the uniformly (13)C- and (15)N-labeled RNA construct has shown that RNA molecule folds into a stable structure consisting of two stem regions separated by a well-defined asymmetric internal loop. Solution-state NMR can make important contribution toward deeper understanding of assembly, folding, and structural features of miRNA:mRNA complexes.
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Affiliation(s)
- Mirko Cevec
- Slovenian NMR Centre, National Institute of Chemistry, Ljubljana, Slovenia
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28
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Jacso T, Grote M, Daus ML, Schmieder P, Keller S, Schneider E, Reif B. Periplasmic loop P2 of the MalF subunit of the maltose ATP binding cassette transporter is sufficient to bind the maltose binding protein MalE. Biochemistry 2009; 48:2216-25. [PMID: 19159328 DOI: 10.1021/bi801376m] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Escherichia coli maltose transporter belongs to the ATP binding cassette (ABC) transporter superfamily. Recently, the crystal structure of the full transporter MalFGK2 in complex with the maltose binding protein (MBP) was determined [Oldham, M. L., et al. (2007) Crystal structure of a catalytic intermediate of the maltose transporter. Nature 450, 515-522]. Using liquid-state NMR, we find that the periplasmic loop P2 of MalF (MalF-P2) folds independently in solution and adopts a well-defined tertiary structure which is similar to the one found in the crystal. MalF-P2 interacts with the maltose binding protein, independent of the transmembrane region of MalF and MalG with an affinity of 10-20 microM, in the presence and absence of substrate. Analysis of residual dipolar coupling (RDC) experiments shows that the conformation of the two individual domains of MalF-P2 is preserved in the absence of MalE and resembles the conformation in the X-ray structure. Upon titration of MalE to MalF-P2, the two domains of MalF-P2 change their relative orientation to accommodate the ligand. In particular, a conformational change of domain 2 of MalF-P2 is induced, which is distinct from the conformation found in the X-ray structure.
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Affiliation(s)
- Tomas Jacso
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Berlin, Germany
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29
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Insights into the dynamics of specific telomeric single-stranded DNA recognition by Pot1pN. J Mol Biol 2009; 387:935-48. [PMID: 19232358 DOI: 10.1016/j.jmb.2009.02.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 01/22/2009] [Accepted: 02/10/2009] [Indexed: 11/23/2022]
Abstract
The N-terminal oligonucleotide/oligosaccharide-binding fold domain of the Schizosaccharomyces pombe protection of telomeres 1 (Pot1) protein, Pot1pN (residues 1-187 of full-length Pot1), specifically recognizes telomeric single-stranded DNA (ssDNA) via a complex series of molecular interactions that are punctuated by unusual internucleotide hydrogen bonds. While the structure of ssDNA-bound Pot1pN provides an initial model for understanding how the Pot1pN-ssDNA complex is assembled and how specific nucleotide recognition occurs, further refinement requires knowledge of the ssDNA-free state of Pot1pN and the dynamic changes that accompany the binding of ssDNA. Using NMR strategies, we found that ssDNA-free Pot1pN adopts a similar overall protein backbone topology as ssDNA-bound Pot1pN does. Although the backbone structure remained relatively unchanged, we observed unexpected differential dynamic changes within the ssDNA-binding pockets of Pot1pN upon binding of cognate ssDNA. These studies support a model in which conformational selection and induced fit play important roles in the recognition of ssDNA by Pot1pN. Furthermore, the studies presented here provide a more comprehensive understanding of how specific nucleotide recognition is achieved by the telomere-end protection family of essential proteins.
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30
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Latham MP, Pardi A. Measurement of imino 1H-1H residual dipolar couplings in RNA. JOURNAL OF BIOMOLECULAR NMR 2009; 43:121-129. [PMID: 19067179 PMCID: PMC2846714 DOI: 10.1007/s10858-008-9293-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 11/12/2008] [Accepted: 11/13/2008] [Indexed: 05/27/2023]
Abstract
Imino (1)H-(15)N residual dipolar couplings (RDCs) provide additional structural information that complements standard (1)H-(1)H NOEs leading to improvements in both the local and global structure of RNAs. Here, we report measurement of imino (1)H-(1)H RDCs for the Iron Responsive Element (IRE) RNA and native E. coli tRNA(Val) using a BEST-Jcomp-HMQC2 experiment. (1)H-(1)H RDCs are observed between the imino protons in G-U wobble base pairs and between imino protons on neighboring base pairs in both RNAs. These imino (1)H-(1)H RDCs complement standard (1)H-(15)N RDCs because the (1)H-(1)H vectors generally point along the helical axis, roughly perpendicular to (1)H-(15)N RDCs. The use of longitudinal relaxation enhancement increased the signal-to-noise of the spectra by ~3.5-fold over the standard experiment. The ability to measure imino (1)H-(1)H RDCs offers a new restraint, which can be used in NMR domain orientation and structural studies of RNAs.
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31
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Jain NU. Use of residual dipolar couplings in structural analysis of protein-ligand complexes by solution NMR spectroscopy. Methods Mol Biol 2009; 544:231-52. [PMID: 19488703 DOI: 10.1007/978-1-59745-483-4_15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Investigation of structure-function relationships in protein complexes, specifically protein-ligand interactions, carry great significance in elucidating the structural and mechanistic bases of molecular recognition events and their role in regulating cell processes. Nuclear magnetic resonance (NMR) spectroscopy is one of the leading structural and analytical techniques in in-depth studies of protein-ligand interactions. Recent advances in NMR methodology such as transverse relaxation-optimized spectroscopy (TROSY) and residual dipolar couplings (RDCs) measured in liquid crystalline alignment medium, offer a viable alternative to traditional nuclear Overhauser enhancement (NOE)-based approaches for structure determination of large protein complexes. RDCs provide a way to constrain the relative orientation of two molecules in complex with each other by aligning their independently determined order tensors. The potential for utilization of RDCs can be extended to proteins with multiple ligands or even multimeric protein-ligand complexes, where symmetry properties of the protein can be taken advantage of. Availability of effective RDC data collection and analysis protocols can certainly aid this process by their incorporation into structure calculation protocols using intramolecular and intermolecular orientational restraints. This chapter discusses in detail some of these protocols including methods for sample preparation in liquid crystalline media, NMR experiments for RDC data collection, as well as software tools for RDC data analysis and protein-ligand complex structure determination.
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Affiliation(s)
- Nitin U Jain
- Cellular and Molecular Biology Department, University of Tennessee, 37996-0840, Knoxville, TN, USA.
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Parish D, Benach J, Liu G, Singarapu KK, Xiao R, Acton T, Su M, Bansal S, Prestegard JH, Hunt J, Montelione GT, Szyperski T. Protein chaperones Q8ZP25_SALTY from Salmonella typhimurium and HYAE_ECOLI from Escherichia coli exhibit thioredoxin-like structures despite lack of canonical thioredoxin active site sequence motif. JOURNAL OF STRUCTURAL AND FUNCTIONAL GENOMICS 2008; 9:41-9. [PMID: 19039680 PMCID: PMC2850599 DOI: 10.1007/s10969-008-9050-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Accepted: 11/10/2008] [Indexed: 10/21/2022]
Abstract
The structure of the 142-residue protein Q8ZP25_SALTY encoded in the genome of Salmonella typhimurium LT2 was determined independently by NMR and X-ray crystallography, and the structure of the 140-residue protein HYAE_ECOLI encoded in the genome of Escherichia coli was determined by NMR. The two proteins belong to Pfam (Finn et al. 34:D247-D251, 2006) PF07449, which currently comprises 50 members, and belongs itself to the 'thioredoxin-like clan'. However, protein HYAE_ECOLI and the other proteins of Pfam PF07449 do not contain the canonical Cys-X-X-Cys active site sequence motif of thioredoxin. Protein HYAE_ECOLI was previously classified as a [NiFe] hydrogenase-1 specific chaperone interacting with the twin-arginine translocation (Tat) signal peptide. The structures presented here exhibit the expected thioredoxin-like fold and support the view that members of Pfam family PF07449 specifically interact with Tat signal peptides.
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Affiliation(s)
- David Parish
- David Parish · Gaohua Liu · Kiran Kumar Singarapu · Thomas Szyperski, Department of Chemistry, Northeast Structural Genomics Consortium, The State University of New York at Buffalo, Buffalo, NY 14260,
- Jordi Benach · Min Su · John F. Hunt, Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027
- Rong Xiao · Thomas Acton · Gaetano T. Montelione, The Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Northeast Structural Genomics Consortium, Rutgers University and Robert Wood Johnson Medical School, Piscataway, NJ 08854
- Sonal Bansal · James H. Prestegard, Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, Athens, Georgia, 30602-4712
| | - Jordi Benach
- David Parish · Gaohua Liu · Kiran Kumar Singarapu · Thomas Szyperski, Department of Chemistry, Northeast Structural Genomics Consortium, The State University of New York at Buffalo, Buffalo, NY 14260,
- Jordi Benach · Min Su · John F. Hunt, Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027
- Rong Xiao · Thomas Acton · Gaetano T. Montelione, The Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Northeast Structural Genomics Consortium, Rutgers University and Robert Wood Johnson Medical School, Piscataway, NJ 08854
- Sonal Bansal · James H. Prestegard, Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, Athens, Georgia, 30602-4712
| | - Goahua Liu
- David Parish · Gaohua Liu · Kiran Kumar Singarapu · Thomas Szyperski, Department of Chemistry, Northeast Structural Genomics Consortium, The State University of New York at Buffalo, Buffalo, NY 14260,
- Jordi Benach · Min Su · John F. Hunt, Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027
- Rong Xiao · Thomas Acton · Gaetano T. Montelione, The Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Northeast Structural Genomics Consortium, Rutgers University and Robert Wood Johnson Medical School, Piscataway, NJ 08854
- Sonal Bansal · James H. Prestegard, Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, Athens, Georgia, 30602-4712
| | - Kiran Kumar Singarapu
- David Parish · Gaohua Liu · Kiran Kumar Singarapu · Thomas Szyperski, Department of Chemistry, Northeast Structural Genomics Consortium, The State University of New York at Buffalo, Buffalo, NY 14260,
- Jordi Benach · Min Su · John F. Hunt, Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027
- Rong Xiao · Thomas Acton · Gaetano T. Montelione, The Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Northeast Structural Genomics Consortium, Rutgers University and Robert Wood Johnson Medical School, Piscataway, NJ 08854
- Sonal Bansal · James H. Prestegard, Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, Athens, Georgia, 30602-4712
| | - Rong Xiao
- David Parish · Gaohua Liu · Kiran Kumar Singarapu · Thomas Szyperski, Department of Chemistry, Northeast Structural Genomics Consortium, The State University of New York at Buffalo, Buffalo, NY 14260,
- Jordi Benach · Min Su · John F. Hunt, Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027
- Rong Xiao · Thomas Acton · Gaetano T. Montelione, The Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Northeast Structural Genomics Consortium, Rutgers University and Robert Wood Johnson Medical School, Piscataway, NJ 08854
- Sonal Bansal · James H. Prestegard, Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, Athens, Georgia, 30602-4712
| | - Thomas Acton
- David Parish · Gaohua Liu · Kiran Kumar Singarapu · Thomas Szyperski, Department of Chemistry, Northeast Structural Genomics Consortium, The State University of New York at Buffalo, Buffalo, NY 14260,
- Jordi Benach · Min Su · John F. Hunt, Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027
- Rong Xiao · Thomas Acton · Gaetano T. Montelione, The Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Northeast Structural Genomics Consortium, Rutgers University and Robert Wood Johnson Medical School, Piscataway, NJ 08854
- Sonal Bansal · James H. Prestegard, Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, Athens, Georgia, 30602-4712
| | - Min Su
- David Parish · Gaohua Liu · Kiran Kumar Singarapu · Thomas Szyperski, Department of Chemistry, Northeast Structural Genomics Consortium, The State University of New York at Buffalo, Buffalo, NY 14260,
- Jordi Benach · Min Su · John F. Hunt, Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027
- Rong Xiao · Thomas Acton · Gaetano T. Montelione, The Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Northeast Structural Genomics Consortium, Rutgers University and Robert Wood Johnson Medical School, Piscataway, NJ 08854
- Sonal Bansal · James H. Prestegard, Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, Athens, Georgia, 30602-4712
| | - Sonal Bansal
- David Parish · Gaohua Liu · Kiran Kumar Singarapu · Thomas Szyperski, Department of Chemistry, Northeast Structural Genomics Consortium, The State University of New York at Buffalo, Buffalo, NY 14260,
- Jordi Benach · Min Su · John F. Hunt, Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027
- Rong Xiao · Thomas Acton · Gaetano T. Montelione, The Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Northeast Structural Genomics Consortium, Rutgers University and Robert Wood Johnson Medical School, Piscataway, NJ 08854
- Sonal Bansal · James H. Prestegard, Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, Athens, Georgia, 30602-4712
| | - James H. Prestegard
- David Parish · Gaohua Liu · Kiran Kumar Singarapu · Thomas Szyperski, Department of Chemistry, Northeast Structural Genomics Consortium, The State University of New York at Buffalo, Buffalo, NY 14260,
- Jordi Benach · Min Su · John F. Hunt, Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027
- Rong Xiao · Thomas Acton · Gaetano T. Montelione, The Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Northeast Structural Genomics Consortium, Rutgers University and Robert Wood Johnson Medical School, Piscataway, NJ 08854
- Sonal Bansal · James H. Prestegard, Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, Athens, Georgia, 30602-4712
| | - John Hunt
- David Parish · Gaohua Liu · Kiran Kumar Singarapu · Thomas Szyperski, Department of Chemistry, Northeast Structural Genomics Consortium, The State University of New York at Buffalo, Buffalo, NY 14260,
- Jordi Benach · Min Su · John F. Hunt, Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027
- Rong Xiao · Thomas Acton · Gaetano T. Montelione, The Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Northeast Structural Genomics Consortium, Rutgers University and Robert Wood Johnson Medical School, Piscataway, NJ 08854
- Sonal Bansal · James H. Prestegard, Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, Athens, Georgia, 30602-4712
| | - Gaetano T. Montelione
- David Parish · Gaohua Liu · Kiran Kumar Singarapu · Thomas Szyperski, Department of Chemistry, Northeast Structural Genomics Consortium, The State University of New York at Buffalo, Buffalo, NY 14260,
- Jordi Benach · Min Su · John F. Hunt, Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027
- Rong Xiao · Thomas Acton · Gaetano T. Montelione, The Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Northeast Structural Genomics Consortium, Rutgers University and Robert Wood Johnson Medical School, Piscataway, NJ 08854
- Sonal Bansal · James H. Prestegard, Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, Athens, Georgia, 30602-4712
| | - Thomas Szyperski
- David Parish · Gaohua Liu · Kiran Kumar Singarapu · Thomas Szyperski, Department of Chemistry, Northeast Structural Genomics Consortium, The State University of New York at Buffalo, Buffalo, NY 14260,
- Jordi Benach · Min Su · John F. Hunt, Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027
- Rong Xiao · Thomas Acton · Gaetano T. Montelione, The Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Northeast Structural Genomics Consortium, Rutgers University and Robert Wood Johnson Medical School, Piscataway, NJ 08854
- Sonal Bansal · James H. Prestegard, Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, Athens, Georgia, 30602-4712
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Characterizing complex dynamics in the transactivation response element apical loop and motional correlations with the bulge by NMR, molecular dynamics, and mutagenesis. Biophys J 2008; 95:3906-15. [PMID: 18621815 DOI: 10.1529/biophysj.108.140285] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The HIV-1 transactivation response element (TAR) RNA binds a variety of proteins and is a target for developing anti-HIV therapies. TAR has two primary binding sites: a UCU bulge and a CUGGGA apical loop. We used NMR residual dipolar couplings, carbon spin relaxation (R(1) and R(2)), and relaxation dispersion (R(1rho)) in conjunction with molecular dynamics and mutagenesis to characterize the dynamics of the TAR apical loop and investigate previously proposed long-range interactions with the distant bulge. Replacement of the wild-type apical loop with a UUCG loop did not significantly affect the structural dynamics at the bulge, indicating that the apical loop and the bulge act largely as independent dynamical recognition centers. The apical loop undergoes complex dynamics at multiple timescales that are likely important for adaptive recognition: U31 and G33 undergo limited motions, G32 is highly flexible at picosecond-nanosecond timescales, and G34 and C30 form a dynamic Watson-Crick basepair in which G34 and A35 undergo a slow (approximately 30 mus) likely concerted looping in and out motion, with A35 also undergoing large amplitude motions at picosecond-nanosecond timescales. Our study highlights the power of combining NMR, molecular dynamics, and mutagenesis in characterizing RNA dynamics.
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Ruan K, Briggman KB, Tolman JR. De novo determination of internuclear vector orientations from residual dipolar couplings measured in three independent alignment media. JOURNAL OF BIOMOLECULAR NMR 2008; 41:61-76. [PMID: 18478335 PMCID: PMC2861045 DOI: 10.1007/s10858-008-9240-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2008] [Accepted: 04/18/2008] [Indexed: 05/03/2023]
Abstract
The straightforward interpretation of solution state residual dipolar couplings (RDCs) in terms of internuclear vector orientations generally requires prior knowledge of the alignment tensor, which in turn is normally estimated using a structural model. We have developed a protocol which allows the requirement for prior structural knowledge to be dispensed with as long as RDC measurements can be made in three independent alignment media. This approach, called Rigid Structure from Dipolar Couplings (RSDC), allows vector orientations and alignment tensors to be determined de novo from just three independent sets of RDCs. It is shown that complications arising from the existence of multiple solutions can be overcome by careful consideration of alignment tensor magnitudes in addition to the agreement between measured and calculated RDCs. Extensive simulations as well applications to the proteins ubiquitin and Staphylococcal protein GB1 demonstrate that this method can provide robust determinations of alignment tensors and amide N-H bond orientations often with better than 10 degrees accuracy, even in the presence of modest levels of internal dynamics.
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Affiliation(s)
- Ke Ruan
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218
| | - Kathryn B. Briggman
- Department of Biophysics, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218
| | - Joel R. Tolman
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218
- Corresponding author: Joel R. Tolman, Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, , Phone: (410) 516-8022, Fax: (410) 516-8420
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35
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Bansal S, Miao X, Adams MWW, Prestegard JH, Valafar H. Rapid classification of protein structure models using unassigned backbone RDCs and probability density profile analysis (PDPA). JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 192:60-8. [PMID: 18321742 PMCID: PMC2699457 DOI: 10.1016/j.jmr.2008.01.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 01/19/2008] [Accepted: 01/29/2008] [Indexed: 05/22/2023]
Abstract
A method of identifying the best structural model for a protein of unknown structure from a list of structural candidates using unassigned 15N1H residual dipolar coupling (RDC) data and probability density profile analysis (PDPA) is described. Ten candidate structures have been obtained for the structural genomics target protein PF2048.1 using ROBETTA. 15N1H residual dipolar couplings have been measured from NMR spectra of the protein in two alignment media and these data have been analyzed using PDPA to rank the models in terms of their ability to represent the actual structure. A number of advantages in using this method to characterize a protein structure become apparent. RDCs can easily and rapidly be acquired, and without the need for assignment, the cost and duration of data acquisition is greatly reduced. The approach is quite robust with respect to imprecise and missing data. In the case of PF2048.1, a 79 residue protein, only 58 and 55 of the total RDC data were observed. The method can accelerate structure determination at higher resolution using traditional NMR spectroscopy by providing a starting point for the addition of NOEs and other NMR structural data.
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Affiliation(s)
- Sonal Bansal
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602
| | - Xijiang Miao
- Computer Science and Engineering, University of South Carolina, Columbia SC 29308, USA
| | | | - James H. Prestegard
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602
| | - Homayoun Valafar
- Computer Science and Engineering, University of South Carolina, Columbia SC 29308, USA
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36
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The hand of the filamentous bacteriophage helix. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2008; 37:1077-82. [DOI: 10.1007/s00249-008-0327-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Revised: 03/27/2008] [Accepted: 04/02/2008] [Indexed: 10/22/2022]
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37
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Latham MP, Hanson P, Brown DJ, Pardi A. Comparison of alignment tensors generated for native tRNA(Val) using magnetic fields and liquid crystalline media. JOURNAL OF BIOMOLECULAR NMR 2008; 40:83-94. [PMID: 18026844 PMCID: PMC2846703 DOI: 10.1007/s10858-007-9212-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2007] [Accepted: 10/24/2007] [Indexed: 05/10/2023]
Abstract
Residual dipolar couplings (RDCs) complement standard NOE distance and J-coupling torsion angle data to improve the local and global structure of biomolecules in solution. One powerful application of RDCs is for domain orientation studies, which are especially valuable for structural studies of nucleic acids, where the local structure of a double helix is readily modeled and the orientations of the helical domains can then be determined from RDC data. However, RDCs obtained from only one alignment media generally result in degenerate solutions for the orientation of multiple domains. In protein systems, different alignment media are typically used to eliminate this orientational degeneracy, where the combination of RDCs from two (or more) independent alignment tensors can be used to overcome this degeneracy. It is demonstrated here for native E. coli tRNA(Val) that many of the commonly used liquid crystalline alignment media result in very similar alignment tensors, which do not eliminate the 4-fold degeneracy for orienting the two helical domains in tRNA. The intrinsic magnetic susceptibility anisotropy (MSA) of the nucleobases in tRNA(Val) was also used to obtain RDCs for magnetic alignment at 800 and 900 MHz. While these RDCs yield a different alignment tensor, the specific orientation of this tensor combined with the high rhombicity for the tensors in the liquid crystalline media only eliminates two of the four degenerate orientations for tRNA(Val). Simulations are used to show that, in optimal cases, the combination of RDCs obtained from liquid crystalline medium and MSA-induced alignment can be used to obtain a unique orientation for the two helical domains in tRNA(Val).
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38
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Silipo A, Zhang Z, Cañada FJ, Molinaro A, Linhardt RJ, Jiménez-Barbero J. Conformational analysis of a dermatan sulfate-derived tetrasaccharide by NMR, molecular modeling, and residual dipolar couplings. Chembiochem 2008; 9:240-52. [PMID: 18072186 PMCID: PMC4135520 DOI: 10.1002/cbic.200700400] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Indexed: 11/08/2022]
Abstract
The solution conformation behavior of a dermatan-derived tetrasaccharide--Delta HexA-(1-->3)-GalNAc4S-beta-(1-->4)-IdoA-alpha-(1-->3)-red-GalNAc4S (S is a sulfate group)--has been explored by means of NMR spectroscopy, especially by NOE-based conformational analysis. The tetrasaccharide was present as four species, two of which are chemically different in the anomeric orientation of the reducing 2-deoxy-2-acetamido-galactose (red-GalNAc) residue, while the other two are the result of different conformations of the iduronic acid (IdoA) unit. The two alpha-beta-interconverting anomers were present in a 0.6:1 ratio. Ring conformations have been defined by analysis of (3)J(H,H) coupling constants and interresidual NOE contacts. Both 2-deoxy-2-acetamido-galactose (GalNAc) residues were found in the (4)C(1) chair conformation, the unsaturated uronic acid (Delta-Hex A) adopts a strongly predominant half-chair (1)H(2) conformation, while the IdoA residue exists either in the (1)C(4) chair or in the (2)S(0) skewed boat geometries, in a 4:1 ratio. There is a moderate flexibility of Phi and Psi torsions as suggested by nuclear Overhauser effects (NOEs), molecular modeling (MM), and molecular dynamics (MD) studies. This was further investigated by residual dipolar couplings (RDCs). One-bond C--H RDCs ((1)D(C,H)) and long-range H-H ((3)D(H,H)) RDCs were measured for the tetrasaccharide in a phage solution and interpreted in combination with restrained MD simulation. The RDC-derived data substantially confirmed the validity of the conformer distribution resulting from the NOE-derived simulations, but allowed an improved definition of the conformational behavior of the oligosaccharides in solution. In summary, the data show a moderate flexibility of the four tetrasaccharide species at the central glycosidic linkage. Differences in the shapes of species with the IdoA in skew and in chair conformations and in the distribution of the sulfate groups have also been highlighted.
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Affiliation(s)
- Alba Silipo
- Centro de Investigaciones Biològicas, CSIC, Ramiro de Maeztu 9,28040 Madrid (Spain)
- Dipartimento di Chimica Organica e Biochimica Università di Napoli “Federico II” Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Napoli (Italy)
| | - Zhenqing Zhang
- Departments of Chemistry and Chemical Biology, Biology, and Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180 (USA)
| | - F. Javier Cañada
- Centro de Investigaciones Biològicas, CSIC, Ramiro de Maeztu 9,28040 Madrid (Spain)
| | - Antonio Molinaro
- Dipartimento di Chimica Organica e Biochimica Università di Napoli “Federico II” Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Napoli (Italy)
| | - Robert J. Linhardt
- Departments of Chemistry and Chemical Biology, Biology, and Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180 (USA)
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Gil RR, Gayathri C, Tsarevsky NV, Matyjaszewski K. Stretched Poly(methyl methacrylate) Gel Aligns Small Organic Molecules in Chloroform. Stereochemical Analysis and Diastereotopic Proton NMR Assignment in Ludartin Using Residual Dipolar Couplings and 3J Coupling Constant Analysis. J Org Chem 2008; 73:840-8. [DOI: 10.1021/jo701871g] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Roberto R. Gil
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Chakicherla Gayathri
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Nicolay V. Tsarevsky
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Krzysztof Matyjaszewski
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
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40
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Staple DW, Venditti V, Niccolai N, Elson-Schwab L, Tor Y, Butcher SE. Guanidinoneomycin B recognition of an HIV-1 RNA helix. Chembiochem 2008; 9:93-102. [PMID: 18058789 PMCID: PMC2782590 DOI: 10.1002/cbic.200700251] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Indexed: 01/16/2023]
Abstract
Aminoglycoside antibiotics are small-molecule drugs that bind RNA. The affinity and specificity of aminoglycoside binding to RNA can be increased through chemical modification, such as guanidinylation. Here, we report the binding of guanidinoneomycin B (GNB) to an RNA helix from the HIV-1 frameshift site. The binding of GNB increases the melting temperature (T(m)) of the frameshift-site RNA by at least 10 degrees C, to a point at which a melting transition is not even observed in 2 M urea. A structure of the complex was obtained by using multidimensional heteronuclear NMR spectroscopic methods. We also used a novel paramagnetic-probe assay to identify the site of GNB binding to the surface of the RNA. GNB makes major-groove contacts to two sets of Watson-Crick bases and is in van der Waals contact with a highly structured ACAA tetraloop. Rings I and II of GNB fit into the major groove and form the binding interface with the RNA, whereas rings III and IV are exposed to the solvent and disordered. The binding of GNB causes a broadening of the major groove across the binding site.
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Affiliation(s)
- David W. Staple
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706 (USA)
| | - Vincenzo Venditti
- Biomolecular Structure Research Center and Dipartimento di Biologia Molecolare, Università di Siena, 53100 Siena (Italy)
| | - Neri Niccolai
- Biomolecular Structure Research Center and Dipartimento di Biologia Molecolare, Università di Siena, 53100 Siena (Italy)
| | - Lev Elson-Schwab
- Department of Chemistry and Biochemistry, University of California-San Diego, La Jolla, CA 92093 (USA)
| | - Yitzhak Tor
- Department of Chemistry and Biochemistry, University of California-San Diego, La Jolla, CA 92093 (USA)
| | - Samuel E. Butcher
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706 (USA)
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41
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Abstract
This chapter reviews the methodologies for RNA structure determination by liquid-state nuclear magnetic resonance (NMR). The routine production of milligram quantities of isotopically labeled RNA remains critical to the success of NMR-based structure studies. The standard method for the preparation of isotopically labeled RNA for structural studies in solution is in vitro transcription from DNA oligonucleotide templates using T7 RNA polymerase and unlabeled or isotopically labeled nucleotide triphosphates (NTPs). The purification of the desired RNA can be performed by either denaturing polyacrylamide gel electrophoresis (PAGE) or anion-exchange chromatography. Our basic strategy for studying RNA in solution by NMR is outlined. The topics covered include RNA resonance assignment, restraint collection, and the structure calculation process. Selected examples of NMR spectra are given for a correctly folded 30 nucleotide-containing RNA.
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42
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Tzakos AG, Easton LE, Lukavsky PJ. Preparation of large RNA oligonucleotides with complementary isotope-labeled segments for NMR structural studies. Nat Protoc 2007; 2:2139-47. [PMID: 17853869 DOI: 10.1038/nprot.2007.306] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
RNA structure determination by solution NMR spectroscopy is often restricted to small RNAs (<15 kDa) owing to the problem of chemical shift degeneracy. A fruitful coupling of novel NMR techniques with segmental RNA labeling methodologies could be a powerful tool to overcome the molecular mass limitation of RNA NMR spectroscopy. Herein, we describe a time- and cost-effective procedure to prepare and purify segmentally labeled large RNAs. Two sets of RNA fragments with complementary labeling schemes, such as one fragment (13)C- and the other (15)N-labeled, are prepared by in vitro transcription from a single plasmid DNA. The desired RNA fragments are excised from the primary transcript by two cis-acting hammerhead ribozymes, yielding the required engineered ends for subsequent, complementary ligation. The resulting RNA oligonucleotides display NMR spectra with greatly reduced resonance overlap and thus enable NMR studies of smaller labeled RNA segments within the native context of a large RNA. The procedure is expected to take 3-4 weeks to implement.
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43
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Affiliation(s)
- Joel R Tolman
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.
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44
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Mertens HDT, Callaghan JM, Swarbrick JD, McConville MJ, Gooley PR. A high-resolution solution structure of a trypanosomatid FYVE domain. Protein Sci 2007; 16:2552-9. [PMID: 17905827 PMCID: PMC2211690 DOI: 10.1110/ps.073009807] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
FYVE domain proteins play key roles in regulating membrane traffic in eukaryotic cells. The FYVE domain displays a remarkable specificity for the head group of the target lipid, phosphatidylinositol 3-phosphate (PtdIns[3]P). We have identified five putative FYVE domain proteins in the genome of the protozoan parasite Leishmania major, three of which are predicted to contain a functional PtdIns(3)P-binding site. The FYVE domain of one of these proteins, LmFYVE-1, bound PtdIns(3)P in liposome-binding assays and targeted GFP to acidified late endosomes/lysosomes in mammalian cells. The high-resolution solution structure of its N-terminal FYVE domain (LmFYVE-1[1-79]) was solved by nuclear magnetic resonance. Functionally significant clusters of residues of the LmFYVE-1 domain involved in PtdIns(3)P binding and dependence on low pH for tight binding were identified. This structure is the first trypanosomatid membrane trafficking protein to be determined and has been refined to high precision and accuracy using residual dipolar couplings.
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Affiliation(s)
- Haydyn D T Mertens
- Department of Biochemistry and Molecular Biology, Institute of Biotechnology and Molecular Science, University of Melbourne, Parkville, Victoria, Australia
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Getz M, Sun X, Casiano-Negroni A, Zhang Q, Al-Hashimi HM. NMR studies of RNA dynamics and structural plasticity using NMR residual dipolar couplings. Biopolymers 2007; 86:384-402. [PMID: 17594140 DOI: 10.1002/bip.20765] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
An increasing number of RNAs are being discovered that perform their functions by undergoing large changes in conformation in response to a variety of cellular signals, including recognition of proteins and small molecular targets, changes in temperature, and RNA synthesis itself. The measurement of NMR residual dipolar couplings (RDCs) in partially aligned systems is providing new insights into the structural plasticity of RNA through combined characterization of large-amplitude collective helix motions and local flexibility in noncanonical regions over a wide window of biologically relevant timescales (<milliseconds). Here, we review RDC methodology for studying RNA structural dynamics and survey what has been learnt thus far from application of these methods. Future methodological challenges are also identified.
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Affiliation(s)
- Melissa Getz
- Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109, USA
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46
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Bailor MH, Musselman C, Hansen AL, Gulati K, Patel DJ, Al-Hashimi HM. Characterizing the relative orientation and dynamics of RNA A-form helices using NMR residual dipolar couplings. Nat Protoc 2007; 2:1536-46. [PMID: 17571061 PMCID: PMC4707013 DOI: 10.1038/nprot.2007.221] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We present a protocol for determining the relative orientation and dynamics of A-form helices in 13C/15N isotopically enriched RNA samples using NMR residual dipolar couplings (RDCs). Non-terminal Watson-Crick base pairs in helical stems are experimentally identified using NOE and trans-hydrogen bond connectivity and modeled using the idealized A-form helix geometry. RDCs measured in the partially aligned RNA are used to compute order tensors describing average alignment of each helix relative to the applied magnetic field. The order tensors are translated into Euler angles defining the average relative orientation of helices and order parameters describing the amplitude and asymmetry of interhelix motions. The protocol does not require complete resonance assignments and therefore can be implemented rapidly to RNAs much larger than those for which complete high-resolution NMR structure determination is feasible. The protocol is particularly valuable for exploring adaptive changes in RNA conformation that occur in response to biologically relevant signals. Following resonance assignments, the procedure is expected to take no more than 2 weeks of acquisition and data analysis time.
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Affiliation(s)
- Maximillian H Bailor
- Department of Chemistry & Biophysics Research Division, The University of Michigan, Ann Arbor, Michigan 48109, USA
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47
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Casiano-Negroni A, Sun X, Al-Hashimi HM. Probing Na(+)-induced changes in the HIV-1 TAR conformational dynamics using NMR residual dipolar couplings: new insights into the role of counterions and electrostatic interactions in adaptive recognition. Biochemistry 2007; 46:6525-35. [PMID: 17488097 PMCID: PMC3319146 DOI: 10.1021/bi700335n] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Many regulatory RNAs undergo large changes in structure upon recognition of proteins and ligands, but the mechanism by which this occurs remains poorly understood. Using NMR residual dipolar coupling (RDCs), we characterized Na+-induced changes in the structure and dynamics of the bulge-containing HIV-1 transactivation response element (TAR) RNA that mirrors changes induced by small molecules bearing a different number of cationic groups. Increasing the Na+ concentration from 25 to 320 mM led to a continuous reduction in the average inter-helical bend angle (from 46 degrees to 22 degrees ), inter-helical twist angle (from 66 degrees to -18 degrees ), and inter-helix flexibility (as measured by an increase in the internal generalized degree of order from 0.56 to 0.74). Similar conformational changes were observed with Mg2+, indicating that nonspecific electrostatic interactions drive the conformational transition, although results also suggest that Na+ and Mg2+ may associate with TAR in distinct modes. The transition can be rationalized on the basis of a population-weighted average of two ensembles comprising an electrostatically relaxed bent and flexible TAR conformation that is weakly associated with counterions and a globally rigid coaxial conformation that has stronger electrostatic potential and association with counterions. The TAR inter-helical orientations that are stabilized by small molecules fall around the metal-induced conformational pathway, indicating that counterions may help predispose the TAR conformation for target recognition. Our results underscore the intricate sensitivity of RNA conformational dynamics to environmental conditions and demonstrate the ability to detect subtle conformational changes using NMR RDCs.
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Affiliation(s)
| | | | - Hashim M. Al-Hashimi
- To whom correspondence should be addressed. H. M. A.: ; telephone (734) 615 3361; fax (734) 647 4865
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48
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Mayer KL, Qu Y, Bansal S, LeBlond PD, Jenney FE, Brereton PS, Adams MWW, Xu Y, Prestegard JH. Structure determination of a new protein from backbone-centered NMR data and NMR-assisted structure prediction. Proteins 2006; 65:480-9. [PMID: 16927360 DOI: 10.1002/prot.21119] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Targeting of proteins for structure determination in structural genomic programs often includes the use of threading and fold recognition methods to exclude proteins belonging to well-populated fold families, but such methods can still fail to recognize preexisting folds. The authors illustrate here a method in which limited amounts of structural data are used to improve an initial homology search and the data are subsequently used to produce a structure by data-constrained refinement of an identified structural template. The data used are primarily NMR-based residual dipolar couplings, but they also include additional chemical shift and backbone-nuclear Overhauser effect data. Using this methodology, a backbone structure was efficiently produced for a 10 kDa protein (PF1455) from Pyrococcus furiosus. Its relationship to existing structures and its probable function are discussed.
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Affiliation(s)
- K L Mayer
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, USA
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49
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Poon DKY, Withers SG, McIntosh LP. Direct demonstration of the flexibility of the glycosylated proline-threonine linker in the Cellulomonas fimi Xylanase Cex through NMR spectroscopic analysis. J Biol Chem 2006; 282:2091-100. [PMID: 17121820 DOI: 10.1074/jbc.m609670200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The modular xylanase Cex (or CfXyn10A) from Cellulomonas fimi consists of an N-terminal catalytic domain and a C-terminal cellulose-binding domain, joined by a glycosylated proline-threonine (PT) linker. To characterize the conformation and dynamics of the Cex linker and the consequences of its modification, we have used NMR spectroscopy to study full-length Cex in its nonglycosylated ( approximately 47 kDa) and glycosylated ( approximately 51 kDa) forms. The PT linker lacks any predominant structure in either form as indicated by random coil amide chemical shifts. Furthermore, heteronuclear (1)H-(15)N nuclear Overhauser effect relaxation measurements demonstrate that the linker is flexible on the ns-to-ps time scale and that glycosylation partially dampens this flexibility. The catalytic and cellulose-binding domains also exhibit identical amide chemical shifts whether in isolation or in the context of either unmodified or glycosylated full-length Cex. Therefore, there are no noncovalent interactions between the two domains of Cex or between either domain and the linker. This conclusion is supported by the distinct (15)N relaxation properties of the two domains, as well as their differential alignment within a magnetic field by Pf1 phage particles. These data demonstrate that the PT linker is a flexible tether, joining the structurally independent catalytic and cellulose-binding domains of Cex in an ensemble of conformations; however, more extended forms may predominate because of restrictions imparted by the alternating proline residues. This supports the postulate that the binding-domain anchors Cex to the surface of cellulose, whereas the linker provides flexibility for the catalytic domain to hydrolyze nearby hemicellulose (xylan) chains.
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Affiliation(s)
- David K Y Poon
- Department of Biochemistry and Molecular Biology, The Protein Engineering Network of Centres of Excellence, and The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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Ghasriani H, Teilum K, Johnsson Y, Fernlund P, Drakenberg T. Solution Structures of Human and Porcine β-Microseminoprotein. J Mol Biol 2006; 362:502-15. [PMID: 16930619 DOI: 10.1016/j.jmb.2006.07.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Revised: 07/10/2006] [Accepted: 07/13/2006] [Indexed: 11/21/2022]
Abstract
Beta-microseminoprotein (MSP) is a small cysteine-rich protein (molecular mass about 10 kDa) first isolated from human seminal plasma and later identified in several other organisms. The function of MSP is not known, but a recent study has shown MSP to bind CRISP-3, a protein present in neutrophilic granulocytes. The amino acid sequence is highly variable between species raising the question of the evolutionary conservation of the 3D structure. Here we present NMR solution structures of both the human and the porcine MSP. The two proteins (sequence identity 51%) have a very similar 3D structure with the secondary structure elements well conserved and with most of the amino acid substitutions causing a change of charge localized to one side of the molecule. MSP is a beta-sheet-rich protein with two distinct domains. The N-terminal domain is composed of a four-stranded beta-sheet, with the strands arranged according to the Greek key-motif, and a less structured part. The C-terminal domain contains two two-stranded beta-sheets with no resemblance to known structural motifs. The two domains, connected to each other by the peptide backbone, one disulfide bond, and interactions between the N and C termini, are oriented to give the molecule a rather extended structure. This global fold differs markedly from that of a previously published structure for porcine MSP, in which the two domains have an entirely different orientation to each other. The difference probably stems from a misinterpretation of ten specific inter-domain NOEs.
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Affiliation(s)
- Houman Ghasriani
- Department of Biophysical Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
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