1
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Matzel T, Martin MW, Herr A, Wacker A, Richter C, Sreeramulu S, Schwalbe H. NMR characterization and ligand binding site of the stem-loop 2 motif from the Delta variant of SARS-CoV-2. RNA (NEW YORK, N.Y.) 2024; 30:779-794. [PMID: 38565242 PMCID: PMC11182009 DOI: 10.1261/rna.079902.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 03/08/2024] [Indexed: 04/04/2024]
Abstract
The stem-loop 2 motif (s2m) in SARS-CoV-2 (SCoV-2) is located in the 3'-UTR. Although s2m has been reported to display characteristics of a mobile genomic element that might lead to an evolutionary advantage, its function has remained unknown. The secondary structure of the original SCoV-2 RNA sequence (Wuhan-Hu-1) was determined by NMR in late 2020, delineating the base-pairing pattern and revealing substantial differences in secondary structure compared to SARS-CoV-1 (SCoV-1). The existence of a single G29742-A29756 mismatch in the upper stem of s2m leads to its destabilization and impedes a complete NMR analysis. With Delta, a variant of concern has evolved with one mutation compared to the original sequence that replaces G29742 by U29742. We show here that this mutation results in a more defined structure at ambient temperature accompanied by a rise in melting temperature. Consequently, we were able to identify >90% of the relevant NMR resonances using a combination of selective RNA labeling and filtered 2D NOESY as well as 4D NMR experiments. We present a comprehensive NMR analysis of the secondary structure, (sub)nanosecond dynamics, and ribose conformation of s2m Delta based on heteronuclear 13C NOE and T 1 measurements and ribose carbon chemical shift-derived canonical coordinates. We further show that the G29742U mutation in Delta has no influence on the druggability of s2m compared to the Wuhan-Hu-1 sequence. With the assignment at hand, we identify the flexible regions of s2m as the primary site for small molecule binding.
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Affiliation(s)
- Tobias Matzel
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Maria Wirtz Martin
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Alexander Herr
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Anna Wacker
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Christian Richter
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Sridhar Sreeramulu
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-Universität Frankfurt, 60438 Frankfurt, Germany
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2
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Zeng D, Abzhanova A, Brown BP, Reiter NJ. Dissecting Monomer-Dimer Equilibrium of an RNase P Protein Provides Insight Into the Synergistic Flexibility of 5' Leader Pre-tRNA Recognition. Front Mol Biosci 2021; 8:730274. [PMID: 34540901 PMCID: PMC8447495 DOI: 10.3389/fmolb.2021.730274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/18/2021] [Indexed: 11/13/2022] Open
Abstract
Ribonuclease P (RNase P) is a universal RNA-protein endonuclease that catalyzes 5' precursor-tRNA (ptRNA) processing. The RNase P RNA plays the catalytic role in ptRNA processing; however, the RNase P protein is required for catalysis in vivo and interacts with the 5' leader sequence. A single P RNA and a P protein form the functional RNase P holoenzyme yet dimeric forms of bacterial RNase P can interact with non-tRNA substrates and influence bacterial cell growth. Oligomeric forms of the P protein can also occur in vitro and occlude the 5' leader ptRNA binding interface, presenting a challenge in accurately defining the substrate recognition properties. To overcome this, concentration and temperature dependent NMR studies were performed on a thermostable RNase P protein from Thermatoga maritima. NMR relaxation (R1, R2), heteronuclear NOE, and diffusion ordered spectroscopy (DOSY) experiments were analyzed, identifying a monomeric species through the determination of the diffusion coefficients (D) and rotational correlation times (τc). Experimental diffusion coefficients and τc values for the predominant monomer (2.17 ± 0.36 * 10-10 m2/s, τ c = 5.3 ns) or dimer (1.87 ± 0.40* 10-10 m2/s, τ c = 9.7 ns) protein assemblies at 45°C correlate well with calculated diffusion coefficients derived from the crystallographic P protein structure (PDB 1NZ0). The identification of a monomeric P protein conformer from relaxation data and chemical shift information enabled us to gain novel insight into the structure of the P protein, highlighting a lack of structural convergence of the N-terminus (residues 1-14) in solution. We propose that the N-terminus of the bacterial P protein is partially disordered and adopts a stable conformation in the presence of RNA. In addition, we have determined the location of the 5' leader RNA in solution and measured the affinity of the 5' leader RNA-P protein interaction. We show that the monomer P protein interacts with RNA at the 5' leader binding cleft that was previously identified using X-ray crystallography. Data support a model where N-terminal protein flexibility is stabilized by holoenzyme formation and helps to accommodate the 5' leader region of ptRNA. Taken together, local structural changes of the P protein and the 5' leader RNA provide a means to obtain optimal substrate alignment and activation of the RNase P holoenzyme.
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Affiliation(s)
- Danyun Zeng
- Department of Chemistry, Marquette University, Milwaukee, WI, United States
| | - Ainur Abzhanova
- Department of Chemistry, Marquette University, Milwaukee, WI, United States
| | - Benjamin P Brown
- Chemical and Physical Biology Program, Medical Scientist Training Program, Vanderbilt University, Nashville, TN, United States.,Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Nicholas J Reiter
- Department of Chemistry, Marquette University, Milwaukee, WI, United States
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3
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Chu CC, Liu B, Plangger R, Kreutz C, Al-Hashimi HM. m6A minimally impacts the structure, dynamics, and Rev ARM binding properties of HIV-1 RRE stem IIB. PLoS One 2019; 14:e0224850. [PMID: 31825959 PMCID: PMC6905585 DOI: 10.1371/journal.pone.0224850] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 11/26/2019] [Indexed: 02/02/2023] Open
Abstract
N6-methyladenosine (m6A) is a ubiquitous RNA post-transcriptional modification found in coding as well as non-coding RNAs. m6A has also been found in viral RNAs where it is proposed to modulate host-pathogen interactions. Two m6A sites have been reported in the HIV-1 Rev response element (RRE) stem IIB, one of which was shown to enhance binding to the viral protein Rev and viral RNA export. However, because these m6A sites have not been observed in other studies mapping m6A in HIV-1 RNA, their significance remains to be firmly established. Here, using optical melting experiments, NMR spectroscopy, and in vitro binding assays, we show that m6A minimally impacts the stability, structure, and dynamics of RRE stem IIB as well as its binding affinity to the Rev arginine-rich-motif (ARM) in vitro. Our results indicate that if present in stem IIB, m6A is unlikely to substantially alter the conformational properties of the RNA. Our results add to a growing view that the impact of m6A on RNA depends on sequence context and Mg2+.
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Affiliation(s)
- Chia-Chieh Chu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, United States of America
| | - Bei Liu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, United States of America
| | - Raphael Plangger
- Institute of Organic Chemistry and Center for Molecular Biosciences CMBI, Universität Innsbruck, Innsbruck, Austria
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences CMBI, Universität Innsbruck, Innsbruck, Austria
| | - Hashim M. Al-Hashimi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, United States of America
- Department of Chemistry, Duke University, Durham, NC, United States of America
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4
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Rangadurai A, Szymaski ES, Kimsey IJ, Shi H, Al-Hashimi HM. Characterizing micro-to-millisecond chemical exchange in nucleic acids using off-resonance R 1ρ relaxation dispersion. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 112-113:55-102. [PMID: 31481159 PMCID: PMC6727989 DOI: 10.1016/j.pnmrs.2019.05.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 05/09/2019] [Accepted: 05/10/2019] [Indexed: 05/10/2023]
Abstract
This review describes off-resonance R1ρ relaxation dispersion NMR methods for characterizing microsecond-to-millisecond chemical exchange in uniformly 13C/15N labeled nucleic acids in solution. The review opens with a historical account of key developments that formed the basis for modern R1ρ techniques used to study chemical exchange in biomolecules. A vector model is then used to describe the R1ρ relaxation dispersion experiment, and how the exchange contribution to relaxation varies with the amplitude and frequency offset of an applied spin-locking field, as well as the population, exchange rate, and differences in chemical shifts of two exchanging species. Mathematical treatment of chemical exchange based on the Bloch-McConnell equations is then presented and used to examine relaxation dispersion profiles for more complex exchange scenarios including three-state exchange. Pulse sequences that employ selective Hartmann-Hahn cross-polarization transfers to excite individual 13C or 15N spins are then described for measuring off-resonance R1ρ(13C) and R1ρ(15N) in uniformly 13C/15N labeled DNA and RNA samples prepared using commercially available 13C/15N labeled nucleotide triphosphates. Approaches for analyzing R1ρ data measured at a single static magnetic field to extract a full set of exchange parameters are then presented that rely on numerical integration of the Bloch-McConnell equations or the use of algebraic expressions. Methods for determining structures of nucleic acid excited states are then reviewed that rely on mutations and chemical modifications to bias conformational equilibria, as well as structure-based approaches to calculate chemical shifts. Applications of the methodology to the study of DNA and RNA conformational dynamics are reviewed and the biological significance of the exchange processes is briefly discussed.
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Affiliation(s)
- Atul Rangadurai
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Eric S Szymaski
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Isaac J Kimsey
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA; Nymirum, 4324 S. Alston Avenue, Durham, NC 27713, USA(1)
| | - Honglue Shi
- Department of Chemistry, Duke University, Durham, NC 27710, USA
| | - Hashim M Al-Hashimi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA; Department of Chemistry, Duke University, Durham, NC 27710, USA.
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5
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Merriman DK, Yuan J, Shi H, Majumdar A, Herschlag D, Al-Hashimi HM. Increasing the length of poly-pyrimidine bulges broadens RNA conformational ensembles with minimal impact on stacking energetics. RNA (NEW YORK, N.Y.) 2018; 24:1363-1376. [PMID: 30012568 PMCID: PMC6140463 DOI: 10.1261/rna.066258.118] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 07/05/2018] [Indexed: 05/03/2023]
Abstract
Helical elements separated by bulges frequently undergo transitions between unstacked and coaxially stacked conformations during the folding and function of noncoding RNAs. Here, we examine the dynamic properties of poly-pyrimidine bulges of varying length (n = 1-4, 7) across a range of Mg2+ concentrations using HIV-1 TAR RNA as a model system and solution NMR spectroscopy. In the absence of Mg2+, helices linked by bulges with n ≥ 3 residues adopt predominantly unstacked conformations (stacked population <15%), whereas one-bulge and two-bulge motifs adopt predominantly stacked conformations (stacked population >74%). In the presence of 3 mM Mg2+, the helices predominantly coaxially stack (stacked population >84%), regardless of bulge length, and the midpoint for the Mg2+-dependent stacking transition is within threefold regardless of bulge length. In the absence of Mg2+, the difference between free energy of interhelical coaxial stacking across the bulge variants is estimated to be ∼2.9 kcal/mol, based on an NMR chemical shift mapping with stacking being more energetically disfavored for the longer bulges. This difference decreases to ∼0.4 kcal/mol in the presence of Mg2+ NMR RDCs and resonance intensity data show increased dynamics in the stacked state with increasing bulge length in the presence of Mg2+ We propose that Mg2+ helps to neutralize the growing electrostatic repulsion in the stacked state with increasing bulge length thereby increasing the number of coaxial conformations that are sampled. Energetically compensated interhelical stacking dynamics may help to maximize the conformational adaptability of RNA and allow a wide range of conformations to be optimally stabilized by proteins and ligands.
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Affiliation(s)
- Dawn K Merriman
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Jiayi Yuan
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
- Department of Biology, Duke University, Durham, North Carolina 27708, USA
| | - Honglue Shi
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Ananya Majumdar
- Biomolecular NMR Facility, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Daniel Herschlag
- Department of Biochemistry, Stanford University, Stanford, California 94305, USA
| | - Hashim M Al-Hashimi
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
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6
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Lan P, Tan M, Zhang Y, Niu S, Chen J, Shi S, Qiu S, Wang X, Peng X, Cai G, Cheng H, Wu J, Li G, Lei M. Structural insight into precursor tRNA processing by yeast ribonuclease P. Science 2018; 362:science.aat6678. [PMID: 30262633 DOI: 10.1126/science.aat6678] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 09/18/2018] [Indexed: 11/02/2022]
Abstract
Ribonuclease P (RNase P) is a universal ribozyme responsible for processing the 5'-leader of pre-transfer RNA (pre-tRNA). Here, we report the 3.5-angstrom cryo-electron microscopy structures of Saccharomyces cerevisiae RNase P alone and in complex with pre-tRNAPhe The protein components form a hook-shaped architecture that wraps around the RNA and stabilizes RNase P into a "measuring device" with two fixed anchors that recognize the L-shaped pre-tRNA. A universally conserved uridine nucleobase and phosphate backbone in the catalytic center together with the scissile phosphate and the O3' leaving group of pre-tRNA jointly coordinate two catalytic magnesium ions. Binding of pre-tRNA induces a conformational change in the catalytic center that is required for catalysis. Moreover, simulation analysis suggests a two-metal-ion SN2 reaction pathway of pre-tRNA cleavage. These results not only reveal the architecture of yeast RNase P but also provide a molecular basis of how the 5'-leader of pre-tRNA is processed by eukaryotic RNase P.
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Affiliation(s)
- Pengfei Lan
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China
| | - Ming Tan
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences (CAS), Shanghai 200031, China.,University of Chinese Academy of Sciences, CAS, Shanghai 200031, China
| | - Yuebin Zhang
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian 116023, China
| | - Shuangshuang Niu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences (CAS), Shanghai 200031, China.,University of Chinese Academy of Sciences, CAS, Shanghai 200031, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Juan Chen
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China
| | - Shaohua Shi
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China
| | - Shuwan Qiu
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Xuejuan Wang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Xiangda Peng
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian 116023, China
| | - Gang Cai
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Hong Cheng
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences (CAS), Shanghai 200031, China
| | - Jian Wu
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China.
| | - Guohui Li
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian 116023, China.
| | - Ming Lei
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China. .,Key laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.,National Facility for Protein Science in Shanghai, Zhangjiang Laboratory, Shanghai, 201210, China.,Shanghai Science Research Center, CAS, Shanghai, 201204, China
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7
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Liu X, Chen Y, Fierke CA. Inner-Sphere Coordination of Divalent Metal Ion with Nucleobase in Catalytic RNA. J Am Chem Soc 2017; 139:17457-17463. [PMID: 29116782 PMCID: PMC6020041 DOI: 10.1021/jacs.7b08755] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Identification of the function of metal ions and the RNA moieties, particularly nucleobases, that bind metal ions is important in RNA catalysis. Here we combine single-atom and abasic substitutions to probe functions of conserved nucleobases in ribonuclease P (RNase P). Structural and biophysical studies of bacterial RNase P propose direct coordination of metal ions by the nucleobases of conserved uridine and guanosine in helix P4 of the RNA subunit (P RNA). To biochemically probe the function of metal ion interactions, we substituted the universally conserved bulged uridine (U51) in the P4 helix of circularly permuted Bacillus subtilis P RNA with 4-thiouridine, 4-deoxyuridine, and abasic modifications and G378/379 with 2-aminopurine, N7-deazaguanosine, and 6-thioguanosine. The functional group modifications of U51 decrease RNase P-catalyzed phosphodiester bond cleavage 16- to 23-fold, as measured by the single-turnover cleavage rate constant. The activity of the 4-thiouridine RNase P is partially rescued by addition of Cd(II) or Mn(II) ions. This is the first time a metal-rescue experiment provides evidence for inner-sphere divalent metal ion coordination with a nucleobase. Modifications of G379 modestly decrease the cleavage activity of RNase P, suggesting outer-sphere coordination of O6 on G379 to a metal ion. These data provide biochemical evidence for catalytically important interactions of the P4 helix of P RNA with metal ions, demonstrating that the bulged uridine coordinates at least one catalytic metal ion through an inner-sphere interaction. The combination of single-atom and abasic nucleotide substitutions provides a powerful strategy to probe functions of conserved nucleobases in large RNAs.
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Affiliation(s)
- Xin Liu
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Yu Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Carol A. Fierke
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
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8
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Sathyamoorthy B, Shi H, Zhou H, Xue Y, Rangadurai A, Merriman DK, Al-Hashimi HM. Insights into Watson-Crick/Hoogsteen breathing dynamics and damage repair from the solution structure and dynamic ensemble of DNA duplexes containing m1A. Nucleic Acids Res 2017; 45:5586-5601. [PMID: 28369571 PMCID: PMC5435913 DOI: 10.1093/nar/gkx186] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 03/06/2017] [Accepted: 03/17/2017] [Indexed: 12/18/2022] Open
Abstract
In the canonical DNA double helix, Watson-Crick (WC) base pairs (bps) exist in dynamic equilibrium with sparsely populated (∼0.02-0.4%) and short-lived (lifetimes ∼0.2-2.5 ms) Hoogsteen (HG) bps. To gain insights into transient HG bps, we used solution-state nuclear magnetic resonance spectroscopy, including measurements of residual dipolar couplings and molecular dynamics simulations, to examine how a single HG bp trapped using the N1-methylated adenine (m1A) lesion affects the structural and dynamic properties of two duplexes. The solution structure and dynamic ensembles of the duplexes reveals that in both cases, m1A forms a m1A•T HG bp, which is accompanied by local and global structural and dynamic perturbations in the double helix. These include a bias toward the BI backbone conformation; sugar repuckering, major-groove directed kinking (∼9°); and local melting of neighboring WC bps. These results provide atomic insights into WC/HG breathing dynamics in unmodified DNA duplexes as well as identify structural and dynamic signatures that could play roles in m1A recognition and repair.
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Affiliation(s)
- Bharathwaj Sathyamoorthy
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Chemistry, Duke University, Durham, NC 27710, USA
| | - Honglue Shi
- Department of Chemistry, Duke University, Durham, NC 27710, USA
| | - Huiqing Zhou
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Yi Xue
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Chemistry, Duke University, Durham, NC 27710, USA
| | - Atul Rangadurai
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | | | - Hashim M. Al-Hashimi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Chemistry, Duke University, Durham, NC 27710, USA
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9
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Klemm BP, Wu N, Chen Y, Liu X, Kaitany KJ, Howard MJ, Fierke CA. The Diversity of Ribonuclease P: Protein and RNA Catalysts with Analogous Biological Functions. Biomolecules 2016; 6:biom6020027. [PMID: 27187488 PMCID: PMC4919922 DOI: 10.3390/biom6020027] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 05/04/2016] [Accepted: 05/06/2016] [Indexed: 12/30/2022] Open
Abstract
Ribonuclease P (RNase P) is an essential endonuclease responsible for catalyzing 5' end maturation in precursor transfer RNAs. Since its discovery in the 1970s, RNase P enzymes have been identified and studied throughout the three domains of life. Interestingly, RNase P is either RNA-based, with a catalytic RNA subunit, or a protein-only (PRORP) enzyme with differential evolutionary distribution. The available structural data, including the active site data, provides insight into catalysis and substrate recognition. The hydrolytic and kinetic mechanisms of the two forms of RNase P enzymes are similar, yet features unique to the RNA-based and PRORP enzymes are consistent with different evolutionary origins. The various RNase P enzymes, in addition to their primary role in tRNA 5' maturation, catalyze cleavage of a variety of alternative substrates, indicating a diversification of RNase P function in vivo. The review concludes with a discussion of recent advances and interesting research directions in the field.
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Affiliation(s)
- Bradley P Klemm
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Nancy Wu
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Yu Chen
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48103, USA.
| | - Xin Liu
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48103, USA.
| | - Kipchumba J Kaitany
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Michael J Howard
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Carol A Fierke
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109, USA.
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48103, USA.
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10
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Mouzakis KD, Dethoff EA, Tonelli M, Al-Hashimi H, Butcher SE. Dynamic motions of the HIV-1 frameshift site RNA. Biophys J 2015; 108:644-54. [PMID: 25650931 PMCID: PMC4317556 DOI: 10.1016/j.bpj.2014.12.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 11/11/2014] [Accepted: 12/05/2014] [Indexed: 12/13/2022] Open
Abstract
The HIV-1 frameshift site (FS) plays a critical role in viral replication. During translation, the HIV-1 FS transitions from a 3-helix to a 2-helix junction RNA secondary structure. The 2-helix junction structure contains a GGA bulge, and purine-rich bulges are common motifs in RNA secondary structure. Here, we investigate the dynamics of the HIV-1 FS 2-helix junction RNA. Interhelical motions were studied under different ionic conditions using NMR order tensor analysis of residual dipolar couplings. In 150 mM potassium, the RNA adopts a 43°(±4°) interhelical bend angle (β) and displays large amplitude, anisotropic interhelical motions characterized by a 0.52(±0.04) internal generalized degree of order (GDOint) and distinct order tensor asymmetries for its two helices (η = 0.26(±0.04) and 0.5(±0.1)). These motions are effectively quenched by addition of 2 mM magnesium (GDOint = 0.87(±0.06)), which promotes a near-coaxial conformation (β = 15°(±6°)) of the two helices. Base stacking in the bulge was investigated using the fluorescent purine analog 2-aminopurine. These results indicate that magnesium stabilizes extrahelical conformations of the bulge nucleotides, thereby promoting coaxial stacking of helices. These results are highly similar to previous studies of the HIV transactivation response RNA, despite a complete lack of sequence similarity between the two RNAs. Thus, the conformational space of these RNAs is largely determined by the topology of their interhelical junctions.
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Affiliation(s)
- Kathryn D Mouzakis
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin
| | - Elizabeth A Dethoff
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina
| | - Marco Tonelli
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin
| | | | - Samuel E Butcher
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin.
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11
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Eichhorn CD, Al-Hashimi HM. Structural dynamics of a single-stranded RNA-helix junction using NMR. RNA (NEW YORK, N.Y.) 2014; 20:782-91. [PMID: 24742933 PMCID: PMC4024633 DOI: 10.1261/rna.043711.113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Many regulatory RNAs contain long single strands (ssRNA) that adjoin secondary structural elements. Here, we use NMR spectroscopy to study the dynamic properties of a 12-nucleotide (nt) ssRNA tail derived from the prequeuosine riboswitch linked to the 3' end of a 48-nt hairpin. Analysis of chemical shifts, NOE connectivity, (13)C spin relaxation, and residual dipolar coupling data suggests that the first two residues (A25 and U26) in the ssRNA tail stack onto the adjacent helix and assume an ordered conformation. The following U26-A27 step marks the beginning of an A6-tract and forms an acute pivot point for substantial motions within the tail, which increase toward the terminal end. Despite substantial internal motions, the ssRNA tail adopts, on average, an A-form helical conformation that is coaxial with the helix. Our results reveal a surprising degree of structural and dynamic complexity at the ssRNA-helix junction, which involves a fine balance between order and disorder that may facilitate efficient pseudoknot formation on ligand recognition.
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Affiliation(s)
- Catherine D. Eichhorn
- Chemical Biology Doctoral Program, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Hashim M. Al-Hashimi
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
- Corresponding authorE-mail
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12
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Abstract
RNA dynamics play a fundamental role in many cellular functions. However, there is no general framework to describe these complex processes, which typically consist of many structural maneuvers that occur over timescales ranging from picoseconds to seconds. Here, we classify RNA dynamics into distinct modes representing transitions between basins on a hierarchical free-energy landscape. These transitions include large-scale secondary-structural transitions at >0.1-s timescales, base-pair/tertiary dynamics at microsecond-to-millisecond timescales, stacking dynamics at timescales ranging from nanoseconds to microseconds, and other "jittering" motions at timescales ranging from picoseconds to nanoseconds. We review various modes within these three different tiers, the different mechanisms by which they are used to regulate function, and how they can be coupled together to achieve greater functional complexity.
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13
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Al-Hashimi HM. NMR studies of nucleic acid dynamics. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 237:191-204. [PMID: 24149218 PMCID: PMC3984477 DOI: 10.1016/j.jmr.2013.08.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 08/23/2013] [Indexed: 05/12/2023]
Abstract
Nucleic acid structures have to satisfy two diametrically opposite requirements; on one hand they have to adopt well-defined 3D structures that can be specifically recognized by proteins; on the other hand, their structures must be sufficiently flexible to undergo very large conformational changes that are required during key biochemical processes, including replication, transcription, and translation. How do nucleic acids introduce flexibility into their 3D structure without losing biological specificity? Here, I describe the development and application of NMR spectroscopic techniques in my laboratory for characterizing the dynamic properties of nucleic acids that tightly integrate a broad set of NMR measurements, including residual dipolar couplings, spin relaxation, and relaxation dispersion with sample engineering and computational approaches. This approach allowed us to obtain fundamental new insights into directional flexibility in nucleic acids that enable their structures to change in a very specific functional manner.
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Affiliation(s)
- Hashim M Al-Hashimi
- Department of Chemistry & Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, MI 48109-1055, USA.
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14
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NMR spectroscopy on domain dynamics in biomacromolecules. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2013; 112:58-117. [DOI: 10.1016/j.pbiomolbio.2013.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Revised: 05/06/2013] [Accepted: 05/07/2013] [Indexed: 12/22/2022]
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15
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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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16
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Abstract
More than 50% of RNA secondary structure is estimated to be A-form helices, which are linked together by various junctions. Here we describe a protocol for computing three interhelical Euler angles describing the relative orientation of helices across RNA junctions. 5' and 3' helices, H1 and H2, respectively, are assigned based on the junction topology. A reference canonical helix is constructed using an appropriate molecular builder software consisting of two continuous idealized A-form helices (iH1 and iH2) with helix axis oriented along the molecular Z-direction running toward the positive direction from iH1 to iH2. The phosphate groups and the carbon and oxygen atoms of the sugars are used to superimpose helix H1 of a target interhelical junction onto the corresponding iH1 of the reference helix. A copy of iH2 is then superimposed onto the resulting H2 helix to generate iH2'. A rotation matrix R is computed, which rotates iH2' into iH2 and expresses the rotation parameters in terms of three Euler angles α(h), β(h) and γ(h). The angles are processed to resolve a twofold degeneracy and to select an overall rotation around the axis of the reference helix. The three interhelical Euler angles define clockwise rotations around the 5' (-γ(h)) and 3' (α(h)) helices and an interhelical bend angle (β(h)). The angles can be depicted graphically to provide a 'Ramachandran'-type view of RNA global structure that can be used to identify unusual conformations as well as to understand variations due to changes in sequence, junction topology and other parameters.
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17
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Abstract
Nuclear ribonuclease (RNase) P is a ubiquitous essential ribonucleoprotein complex, one of only two known RNA-based enzymes found in all three domains of life. The RNA component is the catalytic moiety of RNases P across all phylogenetic domains; it contains a well-conserved core, whereas peripheral structural elements are diverse. RNA components of eukaryotic RNases P tend to be less complex than their bacterial counterparts, a simplification that is accompanied by a dramatic reduction of their catalytic ability in the absence of protein. The size and complexity of the protein moieties increase dramatically from bacterial to archaeal to eukaryotic enzymes, apparently reflecting the delegation of some structural functions from RNA to proteins and, perhaps, in response to the increased complexity of the cellular environment in the more evolutionarily advanced organisms; the reasons for the increased dependence on proteins are not clear. We review current information on RNase P and the closely related universal eukaryotic enzyme RNase MRP, focusing on their functions and structural organization.
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Affiliation(s)
- Olga Esakova
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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18
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Hsieh J, Koutmou KS, Rueda D, Koutmos M, Walter NG, Fierke CA. A divalent cation stabilizes the active conformation of the B. subtilis RNase P x pre-tRNA complex: a role for an inner-sphere metal ion in RNase P. J Mol Biol 2010; 400:38-51. [PMID: 20434461 PMCID: PMC2939038 DOI: 10.1016/j.jmb.2010.04.050] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 04/22/2010] [Accepted: 04/24/2010] [Indexed: 01/25/2023]
Abstract
Metal ions interact with RNA to enhance folding, stabilize structure, and, in some cases, facilitate catalysis. Assigning functional roles to specifically bound metal ions presents a major challenge in analyzing the catalytic mechanisms of ribozymes. Bacillus subtilis ribonuclease P (RNase P), composed of a catalytically active RNA subunit (PRNA) and a small protein subunit (P protein), catalyzes the 5'-end maturation of precursor tRNAs (pre-tRNAs). Inner-sphere coordination of divalent metal ions to PRNA is essential for catalytic activity but not for the formation of the RNase P x pre-tRNA (enzyme-substrate, ES) complex. Previous studies have demonstrated that this ES complex undergoes an essential conformational change (to the ES* conformer) before the cleavage step. Here, we show that the ES* conformer is stabilized by a high-affinity divalent cation capable of inner-sphere coordination, such as Ca(II) or Mg(II). Additionally, a second, lower-affinity Mg(II) activates cleavage catalyzed by RNase P. Structural changes that occur upon binding Ca(II) to the ES complex were determined by time-resolved Förster resonance energy transfer measurements of the distances between donor-acceptor fluorophores introduced at specific locations on the P protein and pre-tRNA 5' leader. These data demonstrate that the 5' leader of pre-tRNA moves 4 to 6 A closer to the PRNA x P protein interface during the ES-to-ES* transition and suggest that the metal-dependent conformational change reorganizes the bound substrate in the active site to form a catalytically competent ES* complex.
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Affiliation(s)
- John Hsieh
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan
| | | | - David Rueda
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan
| | - Markos Koutmos
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan
| | - Nils G. Walter
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan
| | - Carol A. Fierke
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan
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19
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Koutmou KS, Casiano-Negroni A, Getz MM, Pazicni S, Andrews AJ, Penner-Hahn JE, Al-Hashimi HM, Fierke CA. NMR and XAS reveal an inner-sphere metal binding site in the P4 helix of the metallo-ribozyme ribonuclease P. Proc Natl Acad Sci U S A 2010; 107:2479-84. [PMID: 20133747 PMCID: PMC2823894 DOI: 10.1073/pnas.0906319107] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Functionally critical metals interact with RNA through complex coordination schemes that are currently difficult to visualize at the atomic level under solution conditions. Here, we report a new approach that combines NMR and XAS to resolve and characterize metal binding in the most highly conserved P4 helix of ribonuclease P (RNase P), the ribonucleoprotein that catalyzes the divalent metal ion-dependent maturation of the 5' end of precursor tRNA. Extended X-ray absorption fine structure (EXAFS) spectroscopy reveals that the Zn(2+) bound to a P4 helix mimic is six-coordinate, with an average Zn-O/N bond distance of 2.08 A. The EXAFS data also show intense outer-shell scattering indicating that the zinc ion has inner-shell interactions with one or more RNA ligands. NMR Mn(2+) paramagnetic line broadening experiments reveal strong metal localization at residues corresponding to G378 and G379 in B. subtilis RNase P. A new "metal cocktail" chemical shift perturbation strategy involving titrations with , Zn(2+), and confirm an inner-sphere metal interaction with residues G378 and G379. These studies present a unique picture of how metals coordinate to the putative RNase P active site in solution, and shed light on the environment of an essential metal ion in RNase P. Our experimental approach presents a general method for identifying and characterizing inner-sphere metal ion binding sites in RNA in solution.
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20
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Piserchio A, Nair PA, Shuman S, Ghose R. Solution NMR studies of Chlorella virus DNA ligase-adenylate. J Mol Biol 2009; 395:291-308. [PMID: 19913033 DOI: 10.1016/j.jmb.2009.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 11/02/2009] [Accepted: 11/04/2009] [Indexed: 01/31/2023]
Abstract
DNA ligases are essential guardians of genome integrity by virtue of their ability to recognize and seal 3'-OH/5'-phosphate nicks in duplex DNA. The substrate binding and three chemical steps of the ligation pathway are coupled to global and local changes in ligase structure, involving both massive protein domain movements and subtle remodeling of atomic contacts in the active site. Here we applied solution NMR spectroscopy to study the conformational dynamics of the Chlorella virus DNA ligase (ChVLig), a minimized eukaryal ATP-dependent ligase consisting of nucleotidyltransferase, OB, and latch domains. Our analysis of backbone (15)N spin relaxation and (15)N,(1)H residual dipolar couplings of the covalent ChVLig-AMP intermediate revealed conformational sampling on fast (picosecond to nanosecond) and slow timescales (microsecond to millisecond), indicative of interdomain and intradomain flexibility. We identified local and global changes in ChVLig-AMP structure and dynamics induced by phosphate. In particular, the chemical shift perturbations elicited by phosphate were clustered in the peptide motifs that comprise the active site. We hypothesize that phosphate anion mimics some of the conformational transitions that occur when ligase-adenylate interacts with the nick 5'-phosphate.
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Affiliation(s)
- Andrea Piserchio
- Department of Chemistry, The City College of New York, New York, NY 10031, USA
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21
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Zhang Q, Al-Hashimi HM. Domain-elongation NMR spectroscopy yields new insights into RNA dynamics and adaptive recognition. RNA (NEW YORK, N.Y.) 2009; 15:1941-8. [PMID: 19776156 PMCID: PMC2764479 DOI: 10.1261/rna.1806909] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
By simplifying the interpretation of nuclear magnetic resonance spin relaxation and residual dipolar couplings data, recent developments involving the elongation of RNA helices are providing new atomic insights into the dynamical properties that allow RNA structures to change functionally and adaptively. Domain elongation, in concert with spin relaxation measurements, has allowed the detailed characterization of a hierarchical network of local and collective motional modes occurring at nanosecond timescale that mirror the structural rearrangements that take place following adaptive recognition. The combination of domain elongation with residual dipolar coupling measurements has allowed the experimental three-dimensional visualization of very large amplitude rigid-body helix motions in HIV-1 transactivation response element (TAR) that trace out a highly choreographed trajectory in which the helices twist and bend in a correlated manner. The dynamic trajectory allows unbound TAR to sample many of its ligand bound conformations, indicating that adaptive recognition occurs by "conformational selection" rather than "induced fit." These studies suggest that intrinsic flexibility plays essential roles directing RNA conformational changes along specific pathways.
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Affiliation(s)
- Qi Zhang
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, California, 90095, USA
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22
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Nikolova EN, Al-Hashimi HM. Preparation, resonance assignment, and preliminary dynamics characterization of residue specific 13C/15N-labeled elongated DNA for the study of sequence-directed dynamics by NMR. JOURNAL OF BIOMOLECULAR NMR 2009; 45:9-16. [PMID: 19636798 DOI: 10.1007/s10858-009-9350-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2009] [Accepted: 06/19/2009] [Indexed: 05/28/2023]
Abstract
DNA is a highly flexible molecule that undergoes functionally important structural transitions in response to external cellular stimuli. Atomic level spin relaxation NMR studies of DNA dynamics have been limited to short duplexes in which sensitivity to biologically relevant fluctuations occurring at nanosecond timescales is often inadequate. Here, we introduce a method for preparing residue-specific (13)C/(15)N-labeled elongated DNA along with a strategy for establishing resonance assignments and apply the approach to probe fast inter-helical bending motions induced by an adenine tract. Preliminary results suggest the presence of elevated A-tract independent end-fraying internal motions occurring at nanosecond timescales, which evade detection in short DNA constructs and that penetrate deep (7 bp) within the DNA helix and gradually fade away towards the helix interior.
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Affiliation(s)
- Evgenia N Nikolova
- Department of Chemistry, Biophysics and Chemical Biology Program, University of Michigan, 930 North University Avenue, Ann Arbor, MI 48109-1055, USA
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23
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Johnson JE, Hoogstraten CG. Extensive backbone dynamics in the GCAA RNA tetraloop analyzed using 13C NMR spin relaxation and specific isotope labeling. J Am Chem Soc 2009; 130:16757-69. [PMID: 19049467 DOI: 10.1021/ja805759z] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Conformational dynamics play a key role in the properties and functions of proteins and nucleic acids. Heteronuclear NMR spin relaxation is a uniquely powerful site-specific probe of dynamics in proteins and has found increasing applications to nucleotide base side chains and anomeric sites in RNA. Applications to the nucleic acid ribose backbone, however, have been hampered by strong magnetic coupling among ring carbons in uniformly 13C-labeled samples. In this work, we apply a recently developed, metabolically directed isotope labeling scheme that places 13C with high efficiency and specificity at the nucleotide ribose C2' and C4' sites. We take advantage of this scheme to explore backbone dynamics in the well-studied GCAA RNA tetraloop. Using a combination of CPMG (Carr-Purcell-Meiboom-Gill) and R(1rho) relaxation dispersion spectroscopy to explore exchange processes on the microsecond to millisecond time scale, we find an extensive pattern of dynamic transitions connecting a set of relatively well-defined conformations. In many cases, the observed transitions appear to be linked to C3'-endo/C2'-endo sugar pucker transitions of the corresponding nucleotides, and may also be correlated across multiple nucleotides within the tetraloop. These results demonstrate the power of NMR spin relaxation based on alternate-site isotope labeling to open a new window into the dynamic properties of ribose backbone groups in RNA.
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Affiliation(s)
- James E Johnson
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
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24
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Stelzer AC, Frank AT, Bailor MH, Andricioaei I, Al-Hashimi HM. Constructing atomic-resolution RNA structural ensembles using MD and motionally decoupled NMR RDCs. Methods 2009; 49:167-73. [PMID: 19699798 DOI: 10.1016/j.ymeth.2009.08.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 08/15/2009] [Accepted: 08/18/2009] [Indexed: 12/30/2022] Open
Abstract
A broad structural landscape often needs to be characterized in order to fully understand how regulatory RNAs perform their biological functions at the atomic level. We present a protocol for visualizing thermally accessible RNA conformations at atomic-resolution and with timescales extending up to milliseconds. The protocol combines molecular dynamics (MD) simulations with experimental residual dipolar couplings (RDCs) measured in partially aligned (13)C/(15)N isotopically enriched elongated RNA samples. The structural ensembles generated in this manner provide insights into RNA dynamics and its role in functionally important transitions.
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Affiliation(s)
- Andrew C Stelzer
- Department of Chemistry and Biophysics, The University of Michigan, Ann Arbor, MI 48109, USA
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25
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26
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Kazantsev AV, Krivenko AA, Pace NR. Mapping metal-binding sites in the catalytic domain of bacterial RNase P RNA. RNA (NEW YORK, N.Y.) 2009; 15:266-76. [PMID: 19095619 PMCID: PMC2648716 DOI: 10.1261/rna.1331809] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Ribonuclease P (RNase P) is a ribonucleoprotein enzyme that contains a universally conserved, catalytically active RNA component. RNase P RNA requires divalent metal ions for folding, substrate binding, and catalysis. Despite recent advances in understanding the structure of RNase P RNA, no comprehensive analysis of metal-binding sites has been reported, in part due to the poor crystallization properties of this large RNA. We have developed an abbreviated yet still catalytic construct, Bst P7Delta RNA, which contains the catalytic domain of the bacterial RNase P RNA and has improved crystallization properties. We use this mutant RNA as well as the native RNA to map metal-binding sites in the catalytic core of the bacterial RNase P RNA, by anomalous scattering in diffraction analysis. The results provide insight into the interplay between RNA structure and focalization of metal ions, and a structural basis for some previous biochemical observations with RNase P. We use electrostatic calculations to extract the potential functional significance of these metal-binding sites with respect to binding Mg(2+). The results suggest that with at least one important exception of specific binding, these sites mainly map areas of diffuse association of magnesium ions.
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Affiliation(s)
- Alexei V Kazantsev
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, 80309, USA
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27
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Berchanski A, Lapidot A. Bacterial RNase P RNA is a drug target for aminoglycoside-arginine conjugates. Bioconjug Chem 2008; 19:1896-906. [PMID: 18712898 DOI: 10.1021/bc800191u] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ribonuclease P (RNase P) holoenzymes are RNPs composed of RNase P RNA (PRNA) and a variable number of P protein subunits. Primary differences in structure and function between bacterial and eukaryotic RNase P and its indispensability for cell viability make the bacterial enzyme an attractive drug target. On the basis of our previous studies, aminoglycoside-arginine conjugates (AACs) bind to HIV-1 TAR and Rev responsive element (RRE) RNAs significantly more efficiently than neomycin B. Their specific inhibition of bacterial rRNA as well as the findings that the hexa-arginine neomycin derivative (NeoR6) is 500-fold more potent than neomycin B in inhibiting bacterial RNase P, led us to explore the structure-function relationships of AACs in comparison to a new set of aminoglycoside-polyarginine conjugates (APACs). We here present predicted binding modes of AACs and APACs to PRNA. We used a multistep docking approach comprising rigid docking full scans and final refinement of the obtained complexes. Our docking results suggest three possible mechanisms of RNase P inhibition by AACs and APACs: competition with the P protein and pre-tRNA on binding to P1-P4 multihelix junction and to J19/4 region (probably including displacement of Mg2+ ions from the P4 helix) of PRNA; competition with Mg2+ ions near the P15 loop; and competition with the P protein and/or pre-tRNA near the P15 helix and interfering with interactions between the P protein and pre-tRNA at this region. The APACs revealed about 10-fold lower intermolecular energy than AACs, indicating stronger interactions of APACs than AACs with PRNA.
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Affiliation(s)
- Alexander Berchanski
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
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28
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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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29
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Herschlag D, Chu VB. Unwinding RNA's secrets: advances in the biology, physics, and modeling of complex RNAs. Curr Opin Struct Biol 2008; 18:305-14. [PMID: 18555681 PMCID: PMC2574980 DOI: 10.1016/j.sbi.2008.05.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Accepted: 05/07/2008] [Indexed: 01/06/2023]
Abstract
The rapid development of our understanding of the diverse biological roles fulfilled by non-coding RNA has motivated interest in the basic macromolecular behavior, structure, and function of RNA. We focus on two areas in the behavior of complex RNAs. First, we present advances in the understanding of how RNA folding is accomplished in vivo by presenting a mechanism for the action of DEAD-box proteins. Members of this family are intimately associated with almost all cellular processes involving RNA, mediating RNA structural rearrangements and chaperoning their folding. Next, we focus on advances in understanding, and characterizing the basic biophysical forces that govern the folding of complex RNAs. Ultimately we expect that a confluence and synergy between these approaches will lead to profound understanding of RNA and its biology.
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Affiliation(s)
- Daniel Herschlag
- Department of Biochemistry, Stanford University, B400, Beckman Center, Stanford, CA 94305,
| | - Vincent B. Chu
- Department of Applied Physics, Stanford University, GLAM, McCullough 318, 476 Lomita Mall, Stanford, CA 94305,
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30
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Smith JK, Hsieh J, Fierke CA. Importance of RNA-protein interactions in bacterial ribonuclease P structure and catalysis. Biopolymers 2007; 87:329-38. [PMID: 17868095 DOI: 10.1002/bip.20846] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Ribonuclease P (RNase P) is a ribonucleoprotein (RNP) complex that catalyzes the metal-dependent maturation of the 5' end of precursor tRNAs (pre-tRNAs) in all organisms. RNase P is comprised of a catalytic RNA (P RNA), and at least one essential protein (P protein). Although P RNA is the catalytic subunit of the enzyme and is active in the absence of P protein under high salt concentrations in vitro, the protein is still required for enzyme activity in vivo. Therefore, the function of the P protein and how it interacts with both P RNA and pre-tRNA have been the focus of much ongoing research. RNA-protein interactions in RNase P serve a number of critical roles in the RNP including stabilizing the structure, and enhancing the affinity for substrates and metal ions. This review examines the role of RNA-protein interactions in bacterial RNase P from both structural and mechanistic perspectives.
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Affiliation(s)
- J Kristin Smith
- Department of Chemistry, University of Michigan, 930 N. University Avenue, Ann Arbor, MI 48109, USA
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31
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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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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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Sun X, Zhang Q, Al-Hashimi HM. Resolving fast and slow motions in the internal loop containing stem-loop 1 of HIV-1 that are modulated by Mg2+ binding: role in the kissing-duplex structural transition. Nucleic Acids Res 2007; 35:1698-713. [PMID: 17311812 PMCID: PMC1865058 DOI: 10.1093/nar/gkm020] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Stem loop 1 (SL1) is a highly conserved hairpin in the 5'-leader of the human immunodeficiency virus type I that forms a metastable kissing dimer that is converted during viral maturation into a stable duplex with the aid of the nucleocapsid (NC) protein. SL1 contains a highly conserved internal loop that promotes the kissing-duplex transition by a mechanism that remains poorly understood. Using NMR, we characterized internal motions induced by the internal loop in an SL1 monomer that may promote the kissing-duplex transition. This includes micro-to-millisecond secondary structural transitions that cause partial melting of three base-pairs above the internal loop making them key nucleation sites for exchanging strands and nanosecond rigid-body stem motions that can help bring strands into spatial register. We show that while Mg2+ binds to the internal loop and arrests these internal motions, it preserves and/or activates local mobility at internal loop residues G272 and G273 which are implicated in NC binding. By stabilizing SL1 without compromising the accessibility of G272 and G273 for NC binding, Mg2+ may increase the dependence of the kissing-duplex transition on NC binding thus preventing spontaneous transitions from taking place and ensuring that viral RNA and protein maturation occur in concert.
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