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Structural Biology for the Molecular Insight between Aptamers and Target Proteins. Int J Mol Sci 2021; 22:ijms22084093. [PMID: 33920991 PMCID: PMC8071422 DOI: 10.3390/ijms22084093] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/12/2021] [Accepted: 04/14/2021] [Indexed: 02/07/2023] Open
Abstract
Aptamers are promising therapeutic and diagnostic agents for various diseases due to their high affinity and specificity against target proteins. Structural determination in combination with multiple biochemical and biophysical methods could help to explore the interacting mechanism between aptamers and their targets. Regrettably, structural studies for aptamer–target interactions are still the bottleneck in this field, which are facing various difficulties. In this review, we first reviewed the methods for resolving structures of aptamer–protein complexes and for analyzing the interactions between aptamers and target proteins. We summarized the general features of the interacting nucleotides and residues involved in the interactions between aptamers and proteins. Challenges and perspectives in current methodologies were discussed. Approaches for determining the binding affinity between aptamers and target proteins as well as modification strategies for stabilizing the binding affinity of aptamers to target proteins were also reviewed. The review could help to understand how aptamers interact with their targets and how alterations such as chemical modifications in the structures affect the affinity and function of aptamers, which could facilitate the optimization and translation of aptamers-based theranostics.
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Feng X, Ma D, Zhao J, Song Y, Zhu Y, Zhou Q, Ma F, Liu X, Zhong M, Liu Y, Xiong Y, Qiu X, Zhang Z, Zhang H, Zhao Y, Zhang K, Hong X, Zhang Z. UHMK1 promotes gastric cancer progression through reprogramming nucleotide metabolism. EMBO J 2020; 39:e102541. [PMID: 31975428 PMCID: PMC7049804 DOI: 10.15252/embj.2019102541] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 12/02/2019] [Accepted: 12/06/2019] [Indexed: 12/19/2022] Open
Abstract
UHMK1 is a nuclear serine/threonine kinase recently implicated in carcinogenesis. However, the functions and action mechanisms of UHMK1 in the pathogenesis of human gastric cancer (GC) are unclear. Here, we observed that UHMK1 was markedly upregulated in GC. UHMK1 silencing strongly inhibited GC aggressiveness. Interestingly, UHMK1-induced GC progression was mediated primarily via enhancing de novo purine synthesis because inhibiting purine synthesis reversed the effects of UHMK1 overexpression. Mechanistically, UHMK1 activated ATF4, an important transcription factor in nucleotide synthesis, by phosphorylating NCOA3 at Ser (S) 1062 and Thr (T) 1067. This event significantly enhanced the binding of NCOA3 to ATF4 and the expression of purine metabolism-associated target genes. Conversely, deficient phosphorylation of NCOA3 at S1062/T1067 significantly abrogated the function of UHMK1 in GC development. Clinically, Helicobacter pylori and GC-associated UHMK1 mutation induced NCOA3-S1062/T1067 phosphorylation and enhanced the activity of ATF4 and UHMK1. Importantly, the level of UHMK1 was significantly correlated with the level of phospho-NCOA3 (S1062/T1067) in human GC specimens. Collectively, these results show that the UHMK1-activated de novo purine synthesis pathway significantly promotes GC development.
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Affiliation(s)
- Xing Feng
- The Affiliated Hospital of Guilin Medical UniversityGuangxi Key Laboratory of Brain and Cognitive NeuroscienceGuangxi Neurological Diseases Clinical Research CenterGuilinGuangxiChina
- Department of ImmuobiologyYale University School of MedicineNew HavenCTUSA
| | - Dong Ma
- Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Jiabao Zhao
- Department of Gastrointestinal SurgeryZhongshan HospitalSchool of MedicineXiamen UniversityXiamenChina
| | - Yongxi Song
- Department of Surgical Oncology and General SurgeryThe First Hospital of China Medical UniversityShenyangChina
| | - Yuekun Zhu
- Medical CenterDuke UniversityDurhamNCUSA
- Department of General SurgeryThe First Affiliated Hospital of Harbin Medical UniversityHarbinChina
| | - Qingxin Zhou
- Department of OncologyThe Third Affiliated Hospital of Harbin Medical UniversityHarbinChina
| | - Fei Ma
- Department of General SurgeryThe Second Affiliated Hospital of Harbin Medical UniversityHarbinChina
| | - Xing Liu
- Department of NeurosurgeryBeijing Tiantan HospitalCapital Medical UniversityBeijingChina
| | - Mengya Zhong
- Department of Gastrointestinal SurgeryZhongshan HospitalSchool of MedicineXiamen UniversityXiamenChina
| | - Yu Liu
- Department of Gastrointestinal SurgeryZhongshan HospitalSchool of MedicineXiamen UniversityXiamenChina
| | - Yubo Xiong
- Department of Gastrointestinal SurgeryZhongshan HospitalSchool of MedicineXiamen UniversityXiamenChina
| | - Xingfeng Qiu
- Department of Gastrointestinal SurgeryZhongshan HospitalSchool of MedicineXiamen UniversityXiamenChina
| | - Zhen Zhang
- Department of General SurgeryThe First Affiliated Hospital of Anhui Medical UniversityAnhuiChina
| | - Heng Zhang
- Department of Histology and EmbryologyXiang Ya School of MedicineCentral South UniversityChangshaChina
| | - Yongxiang Zhao
- National Center for International Research of Biological Targeting Diagnosis and Therapy (Guangxi Key Laboratory of Biological Targeting Diagnosis and Therapy Research)Guangxi Medical UniversityNanningChina
| | - Kaiguang Zhang
- Department of Digestive DiseaseThe First Affiliated Hospital of USTCAnhui Provincial HospitalUniversity of Science and Technology of ChinaAnhuiChina
| | - Xuehui Hong
- Department of Gastrointestinal SurgeryZhongshan HospitalSchool of MedicineXiamen UniversityXiamenChina
| | - Zhiyong Zhang
- The Affiliated Hospital of Guilin Medical UniversityGuangxi Key Laboratory of Brain and Cognitive NeuroscienceGuangxi Neurological Diseases Clinical Research CenterGuilinGuangxiChina
- Department of SurgeryRobert‐Wood‐Johnson Medical School University HospitalRutgers UniversityThe State University of New JerseyNew BrunswickNJUSA
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Strebitzer E, Nußbaumer F, Kremser J, Tollinger M, Kreutz C. Studying sparsely populated conformational states in RNA combining chemical synthesis and solution NMR spectroscopy. Methods 2018; 148:39-47. [PMID: 29753787 DOI: 10.1016/j.ymeth.2018.05.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 05/07/2018] [Indexed: 12/18/2022] Open
Abstract
Using chemical synthesis and solution NMR spectroscopy, RNA structural ensembles including a major ground state and minor populated excited states can be studied at atomic resolution. In this work, atom-specific 13C labeled RNA building blocks - a 5-13C-uridine and a 2,8-13C2-adenosine building block - are used to introduce isolated 13C-1H-spin topologies into a target RNA to probe such structural ensembles via NMR spectroscopy. First, the 5-13C-uridine 2'-O-TBDMS-phosphoramidite building block was introduced into a 21 nucleotide (nt) tP5c stem construct of the tP5abc subdomain of the Tetrahymena group I ribozyme. Then, the 2,8-13C2-adenosine 2'-O-TBDMS-phosphoramidite building block was incorporated into a 9 kDa and a 15 kD construct derived from the epsilon (ε) RNA element of the duck Hepatitis B virus. The 2,8-13C2-adenosine resonances of the 9 kDa 28 nt sequence could be mapped to the full-length 53 nt construct. The isolated NMR active nuclei pairs were used to probe for low populated excited states (<10%) via 13C-Carr-Purcell-Meiboom-Gill (CPMG)-relaxation dispersion NMR spectroscopy. The 13C-CPMG relaxation dispersion experiment recapitulated a secondary structure switching event in the P5c hairpin of the group I intron construct previously revealed by 15N relaxation dispersion experiments. In the ε-HBV RNA an unfolding event occurring on the millisecond time scale was found in the upper stem in-line with earlier observations. This unpaired conformational state is presumed to be important for the binding of the epsilon reverse transcriptase (RT) enzyme. Thus, a full description of an RNA's folding landscape helps to obtain a deeper understanding of its function, as these high energy conformational states often represent functionally important intermediates involved in (un)folding or ribozyme catalysis.
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Affiliation(s)
- Elisabeth Strebitzer
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Felix Nußbaumer
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Johannes Kremser
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Martin Tollinger
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria.
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4
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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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Le MT, Brown RE, Simon AE, Dayie TK. In vivo, large-scale preparation of uniformly (15)N- and site-specifically (13)C-labeled homogeneous, recombinant RNA for NMR studies. Methods Enzymol 2016; 565:495-535. [PMID: 26577743 DOI: 10.1016/bs.mie.2015.07.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Knowledge of how ribonucleic acid (RNA) structures fold to form intricate, three-dimensional structures has provided fundamental insights into understanding the biological functions of RNA. Nuclear magnetic resonance (NMR) spectroscopy is a particularly useful high-resolution technique to investigate the dynamic structure of RNA. Effective study of RNA by NMR requires enrichment with isotopes of (13)C or (15)N or both. Here, we present a method to produce milligram quantities of uniformly (15)N- and site-specifically (13)C-labeled RNAs using wild-type K12 and mutant tktA Escherichia coli in combination with a tRNA-scaffold approach. The method includes a double selection protocol to obtain an E. coli clone with consistently high expression of the recombinant tRNA-scaffold. We also present protocols for the purification of the tRNA-scaffold from a total cellular RNA extract and the excision of the RNA of interest from the tRNA-scaffold using DNAzymes. Finally, we showcase NMR applications to demonstrate the benefit of using in vivo site-specifically (13)C-labeled RNA.
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Affiliation(s)
- My T Le
- Department of Chemistry and Biochemistry,Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland, USA
| | - Rachel E Brown
- Department of Chemistry and Biochemistry, Department of Cellular Biology and Molecular Genetics, Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland, USA
| | - Anne E Simon
- Department of Chemistry and Biochemistry, Department of Cellular Biology and Molecular Genetics, Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland, USA
| | - T Kwaku Dayie
- Department of Chemistry and Biochemistry,Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland, USA.
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6
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Nelissen FHT, Tessari M, Wijmenga SS, Heus HA. Stable isotope labeling methods for DNA. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2016; 96:89-108. [PMID: 27573183 DOI: 10.1016/j.pnmrs.2016.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/02/2016] [Accepted: 06/02/2016] [Indexed: 06/06/2023]
Abstract
NMR is a powerful method for studying proteins and nucleic acids in solution. The study of nucleic acids by NMR is far more challenging than for proteins, which is mainly due to the limited number of building blocks and unfavorable spectral properties. For NMR studies of DNA molecules, (site specific) isotope enrichment is required to facilitate specific NMR experiments and applications. Here, we provide a comprehensive review of isotope-labeling strategies for obtaining stable isotope labeled DNA as well as specifically stable isotope labeled building blocks required for enzymatic DNA synthesis.
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Affiliation(s)
- Frank H T Nelissen
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, The Netherlands.
| | - Marco Tessari
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, The Netherlands.
| | - Sybren S Wijmenga
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, The Netherlands.
| | - Hans A Heus
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, The Netherlands.
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7
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Chemo-enzymatic labeling for rapid assignment of RNA molecules. Methods 2016; 103:11-7. [PMID: 27090003 DOI: 10.1016/j.ymeth.2016.03.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 03/17/2016] [Accepted: 03/22/2016] [Indexed: 11/22/2022] Open
Abstract
Even though Nuclear Magnetic Resonance (NMR) spectroscopy is one of the few techniques capable of determining atomic resolution structures of RNA, it is constrained by two major problems of chemical shift overlap of resonances and rapid signal loss due to line broadening. Emerging tools to tackle these problems include synthesis of atom specifically labeled or chemically modified nucleotides. Herein we review the synthesis of these nucleotides, the design and production of appropriate RNA samples, and the application and analysis of the NMR experiments that take advantage of these labels.
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8
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Chen B, LeBlanc R, Dayie TK. SAM-II Riboswitch Samples at least Two Conformations in Solution in the Absence of Ligand: Implications for Recognition. Angew Chem Int Ed Engl 2016; 55:2724-7. [PMID: 26800479 DOI: 10.1002/anie.201509997] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 12/18/2015] [Indexed: 11/10/2022]
Abstract
Conformational equilibria are increasingly recognized as pivotal for biological function. Traditional structural analyses provide a static image of conformers in solution that sometimes present conflicting views. From (13) C and (1) H chemical exchange saturation transfer experiments, in concert with ligation and selective labeling strategies, we show that in the absence of metabolite, a Mg(2+) (0-0.5 mm)-bound apo SAM-II riboswitch RNA exists in a minor (≈10 %) partially closed state that rapidly exchanges with a predominantly (≈90 %) open form with a lifetime of ≈32 ms. The base and sugar (H6,C6, H1',C1') chemical shifts of C43 for the dominant conformer are similar to those of a free CMP, but those of the minor apo species are comparable to shifts of CMPs in helical RNA regions. Our results suggest that these transient, low populated states stabilized by Mg(2+) will likely enhance rapid ligand recognition and, we anticipate, will play potentially ubiquitous roles in RNA signaling.
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Affiliation(s)
- Bin Chen
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, Biomolecular Sciences Building (296), 8314 Paint Branch Dr., College Park, MD, 20782, USA
| | - Regan LeBlanc
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, Biomolecular Sciences Building (296), 8314 Paint Branch Dr., College Park, MD, 20782, USA
| | - T Kwaku Dayie
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, Biomolecular Sciences Building (296), 8314 Paint Branch Dr., College Park, MD, 20782, USA.
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9
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Chen B, LeBlanc R, Dayie TK. SAM‐II Riboswitch Samples at least Two Conformations in Solution in the Absence of Ligand: Implications for Recognition. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201509997] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Bin Chen
- Center for Biomolecular Structure and Organization Department of Chemistry and Biochemistry University of Maryland Biomolecular Sciences Building (296), 8314 Paint Branch Dr. College Park MD 20782 USA
| | - Regan LeBlanc
- Center for Biomolecular Structure and Organization Department of Chemistry and Biochemistry University of Maryland Biomolecular Sciences Building (296), 8314 Paint Branch Dr. College Park MD 20782 USA
| | - T. Kwaku Dayie
- Center for Biomolecular Structure and Organization Department of Chemistry and Biochemistry University of Maryland Biomolecular Sciences Building (296), 8314 Paint Branch Dr. College Park MD 20782 USA
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10
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Longhini AP, LeBlanc RM, Becette O, Salguero C, Wunderlich CH, Johnson BA, D'Souza VM, Kreutz C, Dayie TK. Chemo-enzymatic synthesis of site-specific isotopically labeled nucleotides for use in NMR resonance assignment, dynamics and structural characterizations. Nucleic Acids Res 2015; 44:e52. [PMID: 26657632 PMCID: PMC4824079 DOI: 10.1093/nar/gkv1333] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 11/16/2015] [Indexed: 11/12/2022] Open
Abstract
Stable isotope labeling is central to NMR studies of nucleic acids. Development of methods that incorporate labels at specific atomic positions within each nucleotide promises to expand the size range of RNAs that can be studied by NMR. Using recombinantly expressed enzymes and chemically synthesized ribose and nucleobase, we have developed an inexpensive, rapid chemo-enzymatic method to label ATP and GTP site specifically and in high yields of up to 90%. We incorporated these nucleotides into RNAs with sizes ranging from 27 to 59 nucleotides using in vitro transcription: A-Site (27 nt), the iron responsive elements (29 nt), a fluoride riboswitch from Bacillus anthracis (48 nt), and a frame-shifting element from a human corona virus (59 nt). Finally, we showcase the improvement in spectral quality arising from reduced crowding and narrowed linewidths, and accurate analysis of NMR relaxation dispersion (CPMG) and TROSY-based CEST experiments to measure μs-ms time scale motions, and an improved NOESY strategy for resonance assignment. Applications of this selective labeling technology promises to reduce difficulties associated with chemical shift overlap and rapid signal decay that have made it challenging to study the structure and dynamics of large RNAs beyond the 50 nt median size found in the PDB.
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Affiliation(s)
- Andrew P Longhini
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USAfi
| | - Regan M LeBlanc
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USAfi
| | - Owen Becette
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USAfi
| | - Carolina Salguero
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Christoph H Wunderlich
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - Bruce A Johnson
- Structural Biology Initiative, CUNY Advanced Science Research Center, 85 St. Nicholas Terrace, New York, NY 10031, USA One Moon Scientific, Inc., 839 Grant Avenue, Westfield, NJ 07090-2322, USA
| | - Victoria M D'Souza
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - T Kwaku Dayie
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USAfi
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Frank AT, Law SM, Brooks CL. A simple and fast approach for predicting (1)H and (13)C chemical shifts: toward chemical shift-guided simulations of RNA. J Phys Chem B 2014; 118:12168-75. [PMID: 25255209 PMCID: PMC4207130 DOI: 10.1021/jp508342x] [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: 11/30/2022]
Abstract
![]()
We introduce a simple and fast approach
for predicting RNA chemical
shifts from interatomic distances that performs with an accuracy similar
to existing predictors and enables the first chemical shift-restrained
simulations of RNA to be carried out. Our analysis demonstrates that
the applied restraints can effectively guide conformational sampling
toward regions of space that are more consistent with chemical shifts
than the initial coordinates used for the simulations. As such, our
approach should be widely applicable in mapping the conformational
landscape of RNAs via chemical shift-guided molecular dynamics simulations.
The simplicity and demonstrated sensitivity to three-dimensional structure
should also allow our method to be used in chemical shift-based RNA
structure prediction, validation, and refinement.
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Affiliation(s)
- Aaron T Frank
- Department of Chemistry and Biophysics, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
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Kellner S, Ochel A, Thüring K, Spenkuch F, Neumann J, Sharma S, Entian KD, Schneider D, Helm M. Absolute and relative quantification of RNA modifications via biosynthetic isotopomers. Nucleic Acids Res 2014; 42:e142. [PMID: 25129236 PMCID: PMC4191383 DOI: 10.1093/nar/gku733] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
In the resurging field of RNA modifications, quantification is a bottleneck blocking many exciting avenues. With currently over 150 known nucleoside alterations, detection and quantification methods must encompass multiple modifications for a comprehensive profile. LC-MS/MS approaches offer a perspective for comprehensive parallel quantification of all the various modifications found in total RNA of a given organism. By feeding (13)C-glucose as sole carbon source, we have generated a stable isotope-labeled internal standard (SIL-IS) for bacterial RNA, which facilitates relative comparison of all modifications. While conventional SIL-IS approaches require the chemical synthesis of single modifications in weighable quantities, this SIL-IS consists of a nucleoside mixture covering all detectable RNA modifications of Escherichia coli, yet in small and initially unknown quantities. For absolute in addition to relative quantification, those quantities were determined by a combination of external calibration and sample spiking of the biosynthetic SIL-IS. For each nucleoside, we thus obtained a very robust relative response factor, which permits direct conversion of the MS signal to absolute amounts of substance. The application of the validated SIL-IS allowed highly precise quantification with standard deviations<2% during a 12-week period, and a linear dynamic range that was extended by two orders of magnitude.
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Affiliation(s)
- Stefanie Kellner
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Antonia Ochel
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Kathrin Thüring
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Felix Spenkuch
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Jennifer Neumann
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Sunny Sharma
- Institute for Molecular Biosciences, Johann-Wolfgang Goethe University, 60438 Frankfurt am Main, Germany
| | - Karl-Dieter Entian
- Institute for Molecular Biosciences, Johann-Wolfgang Goethe University, 60438 Frankfurt am Main, Germany
| | - Dirk Schneider
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Mark Helm
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
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13
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Dagenais P, Legault P. Preparative separation of ribonucleoside monophosphates by ion-pair reverse-phase HPLC. Methods Mol Biol 2013; 941:247-56. [PMID: 23065566 DOI: 10.1007/978-1-62703-113-4_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Structural and dynamic investigations of RNA by nuclear magnetic resonance (NMR) spectroscopy strongly benefit from isotopic-labeling strategies. Among these, nucleotide-specific and site-specific labeling methods can help tremendously in simplifying complex NMR data, while providing unique opportunities for structural investigation of larger RNAs. Such methods generally require separation of individual isotopically labeled ribonucleoside monophosphates prior to their conversion into nucleoside triphosphates and selective incorporation of these nucleoside triphosphates into the RNA. This chapter provides the experimental details for preparative separation of ribonucleoside monophosphates by ion-pair reverse-phase HPLC. It also describes a quick procedure for clean-up and quality control of the individual ribonucleoside monophosphates.
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Affiliation(s)
- Pierre Dagenais
- Département de Biochimie, Université de Montréal, Montreal, QC, Canada
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14
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Biosynthetic preparation of 13C/15N-labeled rNTPs for high-resolution NMR studies of RNAs. Methods Mol Biol 2013; 941:227-45. [PMID: 23065565 DOI: 10.1007/978-1-62703-113-4_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
High-resolution investigations of the structure and dynamics of RNA molecules by nuclear magnetic resonance (NMR) methodologies require the production of (13)C/(15)N-isotopically labeled samples. A common strategy entails the preparation of (13)C/(15)N-enriched ribonucleoside 5'-triphosphates (rNTPs) to be incorporated into RNA oligomers by in vitro transcription. Here, we describe the methods to obtain isotopically labeled rNTP in a uniform or selective fashion from bacterial cultures, using common and versatile E. coli strains. This chapter also covers procedures for extraction and digestion of the total RNA from bacterial cells, purification of the ribonucleoside 5'-monophosphates and their enzymatic phosphorylation to rNTPs.
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15
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Nelissen FHT, Leunissen EHP, van de Laar L, Tessari M, Heus HA, Wijmenga SS. Fast production of homogeneous recombinant RNA--towards large-scale production of RNA. Nucleic Acids Res 2012; 40:e102. [PMID: 22457065 PMCID: PMC3401473 DOI: 10.1093/nar/gks292] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
In the past decades, RNA molecules have emerged as important players in numerous cellular processes. To understand these processes at the molecular and atomic level, large amounts of homogeneous RNA are required for structural, biochemical and pharmacological investigations. Such RNAs are generally obtained from laborious and costly in vitro transcriptions or chemical synthesis. In 2007, a recombinant RNA technology has been described for the constitutive production of large amounts of recombinant RNA in Escherichia coli using a tRNA-scaffold approach. We demonstrate a general applicable extension to the described approach by introducing the following improvements: (i) enhanced transcription of large recombinant RNAs by T7 RNA polymerase (high transcription rates, versatile), (ii) efficient and facile excision of the RNA of interest from the tRNA-scaffold by dual cis-acting hammerhead ribozyme mediated cleavage and (iii) rapid purification of the RNA of interest employing anion-exchange chromatography or affinity chromatography followed by denaturing polyacrylamide gel electrophoresis. These improvements in the existing method pave the tRNA-scaffold approach further such that any (non-)structured product RNA of a defined length can cost-efficiently be obtained in (multi-)milligram quantities without in vitro enzymatic manipulations.
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Affiliation(s)
- Frank H T Nelissen
- Department of Biophysical Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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Thakur CS, Luo Y, Chen B, Eldho NV, Dayie TK. Biomass production of site selective 13C/15N nucleotides using wild type and a transketolase E. coli mutant for labeling RNA for high resolution NMR. JOURNAL OF BIOMOLECULAR NMR 2012; 52:103-14. [PMID: 22124680 PMCID: PMC3277826 DOI: 10.1007/s10858-011-9586-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 11/06/2011] [Indexed: 05/25/2023]
Abstract
Characterization of the structure and dynamics of nucleic acids by NMR benefits significantly from position specifically labeled nucleotides. Here an E. coli strain deficient in the transketolase gene (tktA) and grown on glucose that is labeled at different carbon sites is shown to facilitate cost-effective and large scale production of useful nucleotides. These nucleotides are site specifically labeled in C1' and C5' with minimal scrambling within the ribose ring. To demonstrate the utility of this labeling approach, the new site-specific labeled and the uniformly labeled nucleotides were used to synthesize a 36-nt RNA containing the catalytically essential domain 5 (D5) of the brown algae group II intron self-splicing ribozyme. The D5 RNA was used in binding and relaxation studies probed by NMR spectroscopy. Key nucleotides in the D5 RNA that are implicated in binding Mg(2+) ions are well resolved. As a result, spectra obtained using selectively labeled nucleotides have higher signal-to-noise ratio compared to those obtained using uniformly labeled nucleotides. Thus, compared to the uniformly (13)C/(15)N-labeled nucleotides, these specifically labeled nucleotides eliminate the extensive (13)C-(13)C coupling within the nitrogenous base and ribose ring, give rise to less crowded and more resolved NMR spectra, and accurate relaxation rates without the need for constant-time or band-selective decoupled NMR experiments. These position selective labeled nucleotides should, therefore, find wide use in NMR analysis of biologically interesting RNA molecules.
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Affiliation(s)
- Chandar S. Thakur
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - Yiling Luo
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - Bin Chen
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - Nadukkudy V. Eldho
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - T. Kwaku Dayie
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
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Thakur CS, Dayie TK. Asymmetry of 13C labeled 3-pyruvate affords improved site specific labeling of RNA for NMR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2012; 52:65-77. [PMID: 22089526 PMCID: PMC3266500 DOI: 10.1007/s10858-011-9582-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Accepted: 10/10/2011] [Indexed: 05/07/2023]
Abstract
Selective isotopic labeling provides an unparalleled window within which to study the structure and dynamics of RNAs by high resolution NMR spectroscopy. Unlike commonly used carbon sources, the asymmetry of (13)C-labeled pyruvate provides selective labeling in both the ribose and base moieties of nucleotides using Escherichia coli variants, that until now were not feasible. Here we show that an E. coli mutant strain that lacks succinate and malate dehydrogenases (DL323) and grown on [3-(13)C]-pyruvate affords ribonucleotides with site specific labeling at C5' (~95%) and C1' (~42%) and minimal enrichment elsewhere in the ribose ring. Enrichment is also achieved at purine C2 and C8 (~95%) and pyrimidine C5 (~100%) positions with minimal labeling at pyrimidine C6 and purine C5 positions. These labeling patterns contrast with those obtained with DL323 E. coli grown on [1, 3-(13)C]-glycerol for which the ribose ring is labeled in all but the C4' carbon position, leading to multiplet splitting of the C1', C2' and C3' carbon atoms. The usefulness of these labeling patterns is demonstrated with a 27-nt RNA fragment derived from the 30S ribosomal subunit. Removal of the strong magnetic coupling within the ribose and base leads to increased sensitivity, substantial simplification of NMR spectra, and more precise and accurate dynamic parameters derived from NMR relaxation measurements. Thus these new labels offer valuable probes for characterizing the structure and dynamics of RNA that were previously limited by the constraint of uniformly labeled nucleotides.
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Affiliation(s)
- Chandar S. Thakur
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - T. Kwaku Dayie
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
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Thakur CS, Dayie TK. Asymmetry of (13)C labeled 3-pyruvate affords improved site specific labeling of RNA for NMR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2011; 51:505-17. [PMID: 22038649 PMCID: PMC3222825 DOI: 10.1007/s10858-011-9581-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 10/11/2011] [Indexed: 05/15/2023]
Abstract
Selective isotopic labeling provides an unparalleled window within which to study the structure and dynamics of RNAs by high resolution NMR spectroscopy. Unlike commonly used carbon sources, the asymmetry of (13)C-labeled pyruvate provides selective labeling in both the ribose and base moieties of nucleotides using E. coli variants, that until now were not feasible. Here we show that an E. coli mutant strain that lacks succinate and malate dehydrogenases (DL323) and grown on [3-(13)C]-pyruvate affords ribonucleotides with site specific labeling at C5' (~95%) and C1' (~42%) and minimal enrichment elsewhere in the ribose ring. Enrichment is also achieved at purine C2 and C8 (~95%) and pyrimidine C5 (~100%) positions with minimal labeling at pyrimidine C6 and purine C5 positions. These labeling patterns contrast with those obtained with DL323 E. coli grown on [1, 3-(13)C]-glycerol for which the ribose ring is labeled in all but the C4' carbon position, leading to multiplet splitting of the C1', C2' and C3' carbon atoms. The usefulness of these labeling patterns is demonstrated with a 27-nt RNA fragment derived from the 30S ribosomal subunit. Removal of the strong magnetic coupling within the ribose and base leads to increased sensitivity, substantial simplification of NMR spectra, and more precise and accurate dynamic parameters derived from NMR relaxation measurements. Thus these new labels offer valuable probes for characterizing the structure and dynamics of RNA that were previously limited by the constraint of uniformly labeled nucleotides.
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Affiliation(s)
- Chandar S Thakur
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, College Park, USA
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Thakur CS, Sama JN, Jackson ME, Chen B, Dayie TK. Selective 13C labeling of nucleotides for large RNA NMR spectroscopy using an E. coli strain disabled in the TCA cycle. JOURNAL OF BIOMOLECULAR NMR 2010; 48:179-92. [PMID: 21057854 PMCID: PMC2988204 DOI: 10.1007/s10858-010-9454-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Accepted: 07/28/2010] [Indexed: 05/05/2023]
Abstract
Escherichia coli (E. coli) is an ideal organism to tailor-make labeled nucleotides for biophysical studies of RNA. Recently, we showed that adding labeled formate enhanced the isotopic enrichment at protonated carbon sites in nucleotides. In this paper, we show that growth of a mutant E. coli strain DL323 (lacking succinate and malate dehydrogenases) on (13)C-2-glycerol and (13)C-1,3-glycerol enables selective labeling at many useful sites for RNA NMR spectroscopy. For DL323 E. coli grown in (13)C-2-glycerol without labeled formate, all the ribose carbon atoms are labeled except the C3' and C5' carbon positions. Consequently the C1', C2' and C4' positions remain singlet. In addition, only the pyrimidine base C6 atoms are substantially labeled to ~96% whereas the C2 and C8 atoms of purine are labeled to ~5%. Supplementing the growth media with (13)C-formate increases the labeling at C8 to ~88%, but not C2. Not unexpectedly, addition of exogenous formate is unnecessary for attaining the high enrichment levels of ~88% for the C2 and C8 purine positions in a (13)C-1,3-glycerol based growth. Furthermore, the ribose ring is labeled in all but the C4' carbon position, such that the C2' and C3' positions suffer from multiplet splitting but the C5' position remains singlet and the C1' position shows a small amount of residual C1'-C2' coupling. As expected, all the protonated base atoms, except C6, are labeled to ~90%. In addition, labeling with (13)C-1,3-glycerol affords an isolated methylene ribose with high enrichment at the C5' position (~90%) that makes it particularly attractive for NMR applications involving CH(2)-TROSY modules without the need for decoupling the C4' carbon. To simulate the tumbling of large RNA molecules, perdeuterated glycerol was added to a mixture of the four nucleotides, and the methylene TROSY experiment recorded at various temperatures. Even under conditions of slow tumbling, all the expected carbon correlations were observed, which indicates this approach of using nucleotides obtained from DL323 E. coli will be applicable to high molecular weight RNA systems.
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Affiliation(s)
- Chandar S. Thakur
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - Jacob N. Sama
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - Melantha E. Jackson
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - Bin Chen
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
| | - T. Kwaku Dayie
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, 1115 Biomolecular Sciences Bldg (#296), College Park, MD 20742-3360 USA
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Thakur CS, Brown ME, Sama JN, Jackson ME, Dayie TK. Growth of wildtype and mutant E. coli strains in minimal media for optimal production of nucleic acids for preparing labeled nucleotides. Appl Microbiol Biotechnol 2010; 88:771-9. [PMID: 20730533 PMCID: PMC2938442 DOI: 10.1007/s00253-010-2813-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2010] [Revised: 07/23/2010] [Accepted: 07/30/2010] [Indexed: 01/27/2023]
Abstract
Since RNAs lie at the center of most cellular processes, there is a need for synthesizing large amounts of RNAs made from stable isotope-labeled nucleotides to advance the study of their structure and dynamics by nuclear magnetic resonance (NMR) spectroscopy. A particularly effective means of obtaining labeled nucleotides is to harvest these nucleotides from bacteria grown in defined minimal media supplemented with 15NH4Cl and various carbon sources. Given the high cost of carbon precursors required for labeling nucleic acids for NMR studies, it becomes important to evaluate the optimal growth for commonly used strains under standard minimal media conditions. Such information is lacking. In this study, we characterize the growth for Escherichia coli strains K12, K10zwf, and DL323 in three minimal media with isotopic-labeled carbon sources of acetate, glycerol, and glycerol combined with formate. Of the three media, the LeMaster-Richards and the Studier media outperform the commonly used M9 media and both support optimal growth of E. coli for the production of nucleotides. However, the growth of all three E. coli strains in acetate is reduced almost twofold compared to growth in glycerol. Analysis of the metabolic pathway and previous gene array studies help to explain this differential growth in glycerol and acetate. These studies should benefit efforts to make selective 13C-15N isotopic-labeled nucleotides for synthesizing biologically important RNAs.
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Affiliation(s)
- Chandar S Thakur
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure & Organization, University of Maryland, 1115 Biomolecular Sciences, Bldg #296, College Park, MD 20742-3360, USA
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