1
|
Flemmich L, Bereiter R, Micura R. Chemical Synthesis of Modified RNA. Angew Chem Int Ed Engl 2024; 63:e202403063. [PMID: 38529723 DOI: 10.1002/anie.202403063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/16/2024] [Accepted: 03/26/2024] [Indexed: 03/27/2024]
Abstract
Ribonucleic acids (RNAs) play a vital role in living organisms. Many of their cellular functions depend critically on chemical modification. Methods to modify RNA in a controlled manner-both in vitro and in vivo-are thus essential to evaluate and understand RNA biology at the molecular and mechanistic levels. The diversity of modifications, combined with the size and uniformity of RNA (made up of only 4 nucleotides) makes its site-specific modification a challenging task that needs to be addressed by complementary approaches. One such approach is solid-phase RNA synthesis. We discuss recent developments in this field, starting with new protection concepts in the ongoing effort to overcome current size limitations. We continue with selected modifications that have posed significant challenges for their incorporation into RNA. These include deazapurine bases required for atomic mutagenesis to elucidate mechanistic aspects of catalytic RNAs, and RNA containing xanthosine, N4-acetylcytidine, 5-hydroxymethylcytidine, 3-methylcytidine, 2'-OCF3, and 2'-N3 ribose modifications. We also discuss the all-chemical synthesis of 5'-capped mRNAs and the enzymatic ligation of chemically synthesized oligoribonucleotides to obtain long RNA with multiple distinct modifications, such as those needed for single-molecule FRET studies. Finally, we highlight promising developments in RNA-catalyzed RNA modification using cofactors that transfer bioorthogonal functionalities.
Collapse
Affiliation(s)
- Laurin Flemmich
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Raphael Bereiter
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| |
Collapse
|
2
|
Radwan M, Jana M, Cairo CW. Facile synthesis of C5-azido derivatives of thiosialosides and 2,3-dehydro-5-N-acetylneuraminic acid (DANA). Carbohydr Res 2024; 536:109013. [PMID: 38185031 DOI: 10.1016/j.carres.2023.109013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/14/2023] [Accepted: 12/14/2023] [Indexed: 01/09/2024]
Abstract
Neuraminic acid (Neu5Ac, also known as sialic acid) is an important monosaccharide found in glycoproteins and glycolipids which plays a vital role in regulation of physiological functions and pathological conditions. The study of sialoglycans has benefitted from the development of glycomimetic probes and inhibitors for proteins and enzymes that interact with and modify neuraminic acid in glycan chains. Methods to access sialoside intermediates with high yield are needed to facilitate the design of new targets. Here, we report the synthesis of C5-azido thiosialosides using a mild method to deprotect the C5-acetamido functional group followed by the use of a diazo-transfer reagent. We examined two diazo-transfer strategies and compared their yields and tolerance of acetate protecting groups. The same methods and comparisons were also performed for the 2,3-dehydro-5-N-acetylneuraminic acid (DANA) scaffold which is commonly used to generate inhibitors of neuraminidase (sialidase) enzymes. We found that C5-azido derivatives of both thiosialosides and DANA could be produced in five or six steps with yields up to 76 % and 83 %, respectively. Diazo-transfer reagents compared in this study were trifluoromethanesulfonyl azide (TfN3) and imidazole-1-sulfonyl azide (ImzSO2N3). We found that both reagents were compatible with this method and showed comparable yields. Finally, we show that C5-azido derivatives can help to avoid O, N-acyl protecting group migration which was observed in C5-NHAc analogs.
Collapse
Affiliation(s)
- Mostafa Radwan
- Department of Chemistry, University of Alberta, Edmonton Alberta, T6G 2G2, Canada
| | - Manas Jana
- Department of Chemistry, University of Alberta, Edmonton Alberta, T6G 2G2, Canada
| | - Christopher W Cairo
- Department of Chemistry, University of Alberta, Edmonton Alberta, T6G 2G2, Canada.
| |
Collapse
|
3
|
Thaler J, Syroegin EA, Breuker K, Polikanov YS, Micura R. Practical Synthesis of N-Formylmethionylated Peptidyl-tRNA Mimics. ACS Chem Biol 2023; 18:2233-2239. [PMID: 37433044 PMCID: PMC10594587 DOI: 10.1021/acschembio.3c00237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 06/22/2023] [Indexed: 07/13/2023]
Abstract
Hydrolysis-resistant RNA-peptide conjugates that mimic peptidyl-tRNAs are frequently needed for structural and functional studies of protein synthesis in the ribosome. Such conjugates are accessible by chemical solid-phase synthesis, allowing for the utmost flexibility of both the peptide and the RNA sequence. Commonly used protection group strategies, however, have severe limitations with respect to generating the characteristic Nα-formylmethionyl terminus because the formyl group of the conjugate synthesized at the solid support is easily cleaved during the final basic deprotection/release step. In this study, we demonstrate a simple solution to the problem by coupling appropriately activated Nα-formyl methionine to the fully deprotected conjugate. The structural integrity of the obtained Nα-formylmethionyl conjugate─and hence the chemoselectivity of the reaction─were verified by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry sequence analysis. Additionally, we confirmed the applicability of our procedure for structural studies by obtaining two structures of the ribosome in complex with either fMAI-nh-ACCA or fMFI-nh-ACCA in the P site and ACC-PMN in the A site of the bacterial ribosome at 2.65 and 2.60 Å resolution, respectively. In summary, our approach for hydrolysis-resistant Nα-formylated RNA-peptide conjugates is synthetically straightforward and opens up new avenues to explore ribosomal translation with high-precision substrate mimics.
Collapse
Affiliation(s)
- Julia Thaler
- Institute
of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Egor A. Syroegin
- Department
of Biological Sciences, University of Illinois
at Chicago, Chicago, Illinois 60607, United States
| | - Kathrin Breuker
- Institute
of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Yury S. Polikanov
- Department
of Biological Sciences, University of Illinois
at Chicago, Chicago, Illinois 60607, United States
- Department
of Pharmaceutical Sciences, University of
Illinois at Chicago, Chicago, Illinois 60607, United States
- Center
for Biomolecular Sciences, University of
Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Ronald Micura
- Institute
of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
- Center
for Biomolecular Sciences, University of
Illinois at Chicago, Chicago, Illinois 60607, United States
| |
Collapse
|
4
|
Polikanov YS, Etheve-Quelquejeu M, Micura R. Synthesis of Peptidyl-tRNA Mimics for Structural Biology Applications. Acc Chem Res 2023; 56:2713-2725. [PMID: 37728742 PMCID: PMC10552525 DOI: 10.1021/acs.accounts.3c00412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Indexed: 09/21/2023]
Abstract
Protein biosynthesis is a central process in all living cells that is catalyzed by a complex molecular machine─the ribosome. This process is termed translation because the language of nucleotides in mRNAs is translated into the language of amino acids in proteins. Transfer RNA (tRNA) molecules charged with amino acids serve as adaptors and recognize codons of mRNA in the decoding center while simultaneously the individual amino acids are assembled into a peptide chain in the peptidyl transferase center (PTC). As the nascent peptide emerges from the ribosome, it is threaded through a long tunnel referred to as a nascent peptide exit tunnel (NPET). The PTC and NPET are the sites targeted by many antibiotics and are thus of tremendous importance from a biomedical perspective and for drug development in the pharmaceutical industry.Researchers have achieved much progress in characterizing ribosomal translation at the molecular level; an impressive number of high-resolution structures of different functional and inhibited states of the ribosome are now available. These structures have significantly contributed to our understanding of how the ribosome interacts with its key substrates, namely, mRNA, tRNAs, and translation factors. In contrast, much less is known about the mechanisms of how small molecules, especially antibiotics, affect ribosomal protein synthesis. This mainly concerns the structural basis of small molecule-NPET interference with cotranslational protein folding and the regulation of protein synthesis. Growing biochemical evidence suggests that NPET plays an active role in the regulation of protein synthesis.Much-needed progress in this field is hampered by the fact that during the preparation of ribosome complexes for structural studies (i.e., X-ray crystallography, cryoelectron microscopy, and NMR spectroscopy) the aminoacyl- or peptidyl-tRNAs are unstable and become hydrolyzed. A solution to this problem is the application of hydrolysis-resistant mimics of aminoacyl- or peptidyl-tRNAs.In this Account, we present an overview of synthetic methods for the generation of peptidyl-tRNA analogs. Modular approaches have been developed that combine (i) RNA and peptide solid-phase synthesis on 3'-aminoacylamino-adenosine resins, (ii) native chemical ligations and Staudinger ligations, (iii) tailoring of tRNAs by the selective cleavage of natural native tRNAs with DNAzymes followed by reassembly with enzymatic ligation to synthetic peptidyl-RNA fragments, and (iv) enzymatic tailing and cysteine charging of the tRNA to obtain modified CCA termini of a tRNA that are chemically ligated to the peptide moiety of interest. With this arsenal of tools, in principle, any desired sequence of a stably linked peptidyl-tRNA mimic is accessible. To underline the significance of the synthetic conjugates, we briefly point to the most critical applications that have shed new light on the molecular mechanisms underlying the context-specific activity of ribosome-targeting antibiotics, ribosome-dependent incorporation of multiple consecutive proline residues, the incorporation of d-amino acids, and tRNA mischarging.Furthermore, we discuss new types of stably charged tRNA analogs, relying on triazole- and squarate (instead of amide)-linked conjugates. Those have pushed forward our mechanistic understanding of nonribosomal peptide synthesis, where aminoacyl-tRNA-dependent enzymes are critically involved in various cellular processes in primary and secondary metabolism and in bacterial cell wall synthesis.
Collapse
Affiliation(s)
- Yury S. Polikanov
- Department
of Biological Sciences, University of Illinois
at Chicago, Chicago, Illinois 60607, United States
- Department
of Pharmaceutical Sciences, University of
Illinois at Chicago, Chicago, Illinois 60607, United States
- Center for
Biomolecular Sciences, University of Illinois
at Chicago, Chicago, Illinois 60607, United States
| | - Mélanie Etheve-Quelquejeu
- Université
Paris Cité, CNRS, Laboratoire de Chimie et Biochimie Pharmacologiques
et Toxicologiques, Paris F-75006, France
| | - Ronald Micura
- Institute
of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| |
Collapse
|
5
|
Bristiel A, Cadinot M, Pizzonero M, Taran F, Urban D, Guignard R, Guianvarc'h D. 2'-Modified Thymidines with Bioorthogonal Cyclopropene or Sydnone as Building Blocks for Copper-Free Postsynthetic Functionalization of Chemically Synthesized Oligonucleotides. Bioconjug Chem 2023; 34:1613-1621. [PMID: 37669427 DOI: 10.1021/acs.bioconjchem.3c00284] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
The development of facile methods for conjugating relevant probes, ligands, or delivery agents onto oligonucleotides (ONs) is highly desirable both for fundamental studies in chemical biology and for improving the pharmacology of ONs in medicinal chemistry. Numerous efforts have been focused on the introduction of bioorthogonal groups onto phosphoramidite building blocks, allowing the controlled chemical synthesis of reactive ONs for postsynthetic modifications. Among these building blocks, alkyne, cyclooctynes, trans-cyclooctene, and norbornene have been proved to be compatible with automated solid-phase chemistry. Herein, we present the development of novel 2'-functionalized nucleoside phosphoramidite monomers comprising bioorthogonal methylcyclopropene or sydnone moieties and their introduction for the first time to ON solid-phase synthesis. Traceless ON postsynthetic modifications with reactive complementary probes were successfully achieved through either inverse electron-demand Diels-Alder (iEDDA) reactions or strain-promoted sydnone-alkyne cycloaddition (SPSAC). These results expand the set of bioorthogonal phosphoramidite building blocks to generate ONs for postsynthetic labeling.
Collapse
Affiliation(s)
- Alexandra Bristiel
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), UMR 8182, 91405, Orsay, France
- Unité Drug Design Small Molecules, Institut de Recherche et Développement Servier Paris-Saclay, 22 route 128, Gif-sur-Yvette 91190, France
| | - Manon Cadinot
- Unité Drug Design Small Molecules, Institut de Recherche et Développement Servier Paris-Saclay, 22 route 128, Gif-sur-Yvette 91190, France
| | - Mathieu Pizzonero
- Unité Drug Design Small Molecules, Institut de Recherche et Développement Servier Paris-Saclay, 22 route 128, Gif-sur-Yvette 91190, France
| | - Frédéric Taran
- CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SCBM, Université Paris-Saclay, Gif-sur-Yvette 91191, France
| | - Dominique Urban
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), UMR 8182, 91405, Orsay, France
| | - Raphaël Guignard
- Unité Drug Design Small Molecules, Institut de Recherche et Développement Servier Paris-Saclay, 22 route 128, Gif-sur-Yvette 91190, France
| | - Dominique Guianvarc'h
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), UMR 8182, 91405, Orsay, France
| |
Collapse
|
6
|
Moreno S, Ramos Pittol JM, Hartl M, Micura R. Robust synthesis of 2'-azido modified RNA from 2'-amino precursors by diazotransfer reaction. Org Biomol Chem 2022; 20:7845-7850. [PMID: 36172831 DOI: 10.1039/d2ob01560a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Azides are versatile bioorthogonal reporter moieties that are commonly used for site-specific labeling and functionalization of RNA to probe its biology. The preparation of azido modified nucleic acids by solid-phase synthesis is problematic due to the inherent reactivity of P(III) species with azides according to the Staudinger reaction. Various strategies have been developed to bypass this limitation and are often time-consuming, low-yielding and labor-intensive. In particular, the synthesis of RNA with internal 2'-azido modifications is restricted to a single approach that employs P(V) chemistry instead of the widely used P(III) phosphoramidite chemistry. To fill this methodological gap, we present a novel convenient path toward 2'-azido RNA from readily accessible 2'-amino RNA through treatment with the diazotizing reagent fluorosulfuryl azide (FSO2N3). A diazotransfer reaction was established for oligoribonucleotides of different lengths and secondary structures. The robustness of the approach was further demonstrated for RNAs containing multiple 2'-azido moieties and for RNAs containing other sensitive modifications such as thiouridine or methylated nucleobases with a positive charge. The synthetic ease of generating 2'-azido RNA will pave the way for biotechnological applications, in particular for siRNA technologies and for referencing the growing number of RNA metabolic labeling approaches that rely on 2'-azido nucleosides.
Collapse
Affiliation(s)
- Sarah Moreno
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria.
| | - José M Ramos Pittol
- Institute of Biochemistry, Center for Chemistry and Biomedicine (CCB) Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Markus Hartl
- Institute of Biochemistry, Center for Chemistry and Biomedicine (CCB) Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Ronald Micura
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria.
| |
Collapse
|
7
|
Müggenburg F, Müller S. Azide-modified Nucleosides as Versatile Tools for Bioorthogonal Labeling and Functionalization. CHEM REC 2022; 22:e202100322. [PMID: 35189013 DOI: 10.1002/tcr.202100322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 02/10/2022] [Accepted: 02/10/2022] [Indexed: 02/06/2023]
Abstract
Azide-modified nucleosides are important building blocks for RNA and DNA functionalization by click chemistry based on azide-alkyne cycloaddition. This has put demand on synthetic chemistry to develop approaches for the preparation of azide-modified nucleoside derivatives. We review here the available methods for the synthesis of various nucleosides decorated with azido groups at the sugar residue or nucleobase, their incorporation into oligonucleotides and cellular RNAs, and their application in azide-alkyne cycloadditions for labelling and functionalization.
Collapse
Affiliation(s)
- Frederik Müggenburg
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Straße 4, 17487, Greifswald, Germany
| | - Sabine Müller
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Straße 4, 17487, Greifswald, Germany
| |
Collapse
|
8
|
Liu H, Wang Y, Zhou X. Labeling and sequencing nucleic acid modifications using bio-orthogonal tools. RSC Chem Biol 2022; 3:994-1007. [PMID: 35975003 PMCID: PMC9347354 DOI: 10.1039/d2cb00087c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 06/20/2022] [Indexed: 11/25/2022] Open
Abstract
The bio-orthogonal reaction is a type of reaction that can occur within a cell without interfering with the active components of the cell. Bio-orthogonal reaction techniques have been used to label and track the synthesis, metabolism, and interactions of distinct biomacromolecules in cells. Thus, it is a handy tool for analyzing biological macromolecules within cells. Nucleic acid modifications are widely distributed in DNA and RNA in cells and play a critical role in regulating physiological and pathological cellular activities. Utilizing bio-orthogonal tools to study modified bases is a critical and worthwhile research direction. The development of bio-orthogonal reactions focusing on nucleic acid modifications has enabled the mapping of nucleic acid modifications in DNA and RNA. This review discusses the recent advances in bio-orthogonal labeling and sequencing nucleic acid modifications in DNA and RNA. Labeling nucleic acid modifications using bio-orthogonal tools, then sequencing and imaging the labeled modifications in DNA and RNA.![]()
Collapse
Affiliation(s)
- Hui Liu
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Yafen Wang
- School of Public Health, Wuhan University, Wuhan 430071, China
| | - Xiang Zhou
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| |
Collapse
|
9
|
Müggenburg F, Biallas A, Debiais M, Smietana M, Müller S. Azido Functionalized Nucleosides Linked to Controlled Pore Glass as Suitable Starting Materials for Oligonucleotide Synthesis by the Phosphoramidite Approach. European J Org Chem 2021. [DOI: 10.1002/ejoc.202101140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Frederik Müggenburg
- Institut für Biochemie Universität Greifswald Felix-Hausdorff-Straße 4 17487 Greifswald Germany
| | - Alexander Biallas
- Institut für Biochemie Universität Greifswald Felix-Hausdorff-Straße 4 17487 Greifswald Germany
| | - Mégane Debiais
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM Place Eugène Bataillon 34095 Montpellier France
| | - Michael Smietana
- Institut des Biomolécules Max Mousseron Université de Montpellier, CNRS, ENSCM Place Eugène Bataillon 34095 Montpellier France
| | - Sabine Müller
- Institut für Biochemie Universität Greifswald Felix-Hausdorff-Straße 4 17487 Greifswald Germany
| |
Collapse
|
10
|
Krasheninina OA, Thaler J, Erlacher MD, Micura R. Amine-to-Azide Conversion on Native RNA via Metal-Free Diazotransfer Opens New Avenues for RNA Manipulations. Angew Chem Int Ed Engl 2021; 60:6970-6974. [PMID: 33400347 PMCID: PMC8048507 DOI: 10.1002/anie.202015034] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/19/2020] [Indexed: 12/12/2022]
Abstract
A major challenge in the field of RNA chemistry is the identification of selective and quantitative conversion reactions on RNA that can be used for tagging and any other RNA tool development. Here, we introduce metal-free diazotransfer on native RNA containing an aliphatic primary amino group using the diazotizing reagent fluorosulfuryl azide (FSO2 N3 ). The reaction provides the corresponding azide-modified RNA in nearly quantitatively yields without affecting the nucleobase amino groups. The obtained azido-RNA can then be further processed utilizing well-established bioortho-gonal reactions, such as azide-alkyne cycloadditions (Click) or Staudinger ligations. We exemplify the robustness of this approach for the synthesis of peptidyl-tRNA mimics and for the pull-down of 3-(3-amino-3-carboxypropyl)uridine (acp3 U)- and lysidine (k2 C)-containing tRNAs of an Escherichia coli tRNA pool isolated from cellular extracts. Our approach therefore adds a new dimension to the targeted chemical manipulation of diverse RNA species.
Collapse
Affiliation(s)
- Olga A. Krasheninina
- Institute of Organic Chemistry and Center for Molecular BiosciencesUniversity of InnsbruckInnrain 80–826020InnsbruckAustria
| | - Julia Thaler
- Institute of Organic Chemistry and Center for Molecular BiosciencesUniversity of InnsbruckInnrain 80–826020InnsbruckAustria
| | - Matthias D. Erlacher
- Institute of Genomics and RNomicsBiocenterMedical University of InnsbruckInnrain 80–826020InnsbruckAustria
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular BiosciencesUniversity of InnsbruckInnrain 80–826020InnsbruckAustria
| |
Collapse
|