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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.
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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
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2
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Li NS, Dai Q, Weissman B, Harris ME, Piccirilli JA. A general and efficient approach to synthesize the phosphoramidites of 5'- 18O labeled purine nucleosides. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2023; 42:930-943. [PMID: 37233721 PMCID: PMC10529648 DOI: 10.1080/15257770.2023.2218421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 05/12/2023] [Accepted: 05/22/2023] [Indexed: 05/27/2023]
Abstract
5'-18O labeled RNA oligos are important probes to investigate the mechanism of 2'-O-transphosphorylation reactions. Here we describe a general and efficient synthetic approach to the phosphoramidite derivatives of 5'-18O labeled nucleosides starting from the corresponding commercially available 5'-O-DMT protected nucleosides. Using this method, we prepared 5'-18O-guanosine phosphoramidite in 8 steps (13.2% overall yield), 5'-18O-adenosine phosphoramidite in 9 steps (10.1% overall yield) and 5'-18O-2'-deoxyguanosine phosphoramidite in 6 steps (12.8% overall yield). These 5'-18O labeled phosphoramidites can be incorporated into RNA oligos by solid phase synthesis for determination of heavy atom isotope effects in RNA 2'-O-transphosphorylation reactions.
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Affiliation(s)
- Nan-Sheng Li
- Department of Biochemistry & Molecular Biology, University of Chicago, Chicago, Illinois, USA
| | - Qing Dai
- Department of Chemistry, University of Chicago, Chicago, Illinois, USA
| | - Benjamin Weissman
- Department of Chemistry, University of Chicago, Chicago, Illinois, USA
| | - Michael E Harris
- Department of Chemistry, University of Florida, Gainesville, Florida, USA
| | - Joseph A Piccirilli
- Department of Biochemistry & Molecular Biology, University of Chicago, Chicago, Illinois, USA
- Department of Chemistry, University of Chicago, Chicago, Illinois, USA
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3
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Bege M, Kiss A, Bereczki I, Hodek J, Polyák L, Szemán-Nagy G, Naesens L, Weber J, Borbás A. Synthesis and Anticancer and Antiviral Activities of C-2′-Branched Arabinonucleosides. Int J Mol Sci 2022; 23:ijms232012566. [PMID: 36293420 PMCID: PMC9603951 DOI: 10.3390/ijms232012566] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/07/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022] Open
Abstract
d-Arabinofuranosyl-pyrimidine and -purine nucleoside analogues containing alkylthio-, acetylthio- or 1-thiosugar substituents at the C2’ position were prepared from the corresponding 3’,5’-O-silylene acetal-protected nucleoside 2’-exomethylenes by photoinitiated, radical-mediated hydrothiolation reactions. Although the stereochemical outcome of the hydrothiolation depended on the structure of both the thiol and the furanoside aglycone, in general, high d-arabino selectivity was obtained. The cytotoxic effect of the arabinonucleosides was studied on tumorous SCC (mouse squamous cell) and immortalized control HaCaT (human keratinocyte) cell lines by MTT assay. Three pyrimidine nucleosides containing C2’-butylsulfanylmethyl or -acetylthiomethyl groups showed promising cytotoxicity at low micromolar concentrations with good selectivity towards tumor cells. SAR analysis using a methyl β-d-arabinofuranoside reference compound showed that the silyl-protecting group, the nucleobase and the corresponding C2’ substituent are crucial for the cell growth inhibitory activity. The effects of the three most active nucleoside analogues on parameters indicative of cytotoxicity, such as cell size, division time and cell generation time, were investigated by near-infrared live cell imaging, which showed that the 2’-acetylthiomethyluridine derivative induced the most significant functional and morphological changes. Some nucleoside analogues also exerted anti-SARS-CoV-2 and/or anti-HCoV-229E activity with low micromolar EC50 values; however, the antiviral activity was always accompanied by significant cytotoxicity.
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Affiliation(s)
- Miklós Bege
- Department of Pharmaceutical Chemistry, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
- Institute of Healthcare Industry, University of Debrecen, Nagyerdei krt 98, 4032 Debrecen, Hungary
- MTA-DE Molecular Recognition and Interaction Research Group, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Alexandra Kiss
- Department of Biotechnology and Microbiology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Ilona Bereczki
- Department of Pharmaceutical Chemistry, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
- National Laboratory of Virology, University of Pécs, Ifjúság útja 20, 7624 Pécs, Hungary
| | - Jan Hodek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, CZ-16000 Prague, Czech Republic
| | - Lenke Polyák
- Department of Biotechnology and Microbiology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Gábor Szemán-Nagy
- Department of Biotechnology and Microbiology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Lieve Naesens
- Rega Institute for Medical Research, KU Leuven, B-3000 Leuven, Belgium
| | - Jan Weber
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, CZ-16000 Prague, Czech Republic
| | - Anikó Borbás
- Department of Pharmaceutical Chemistry, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
- National Laboratory of Virology, University of Pécs, Ifjúság útja 20, 7624 Pécs, Hungary
- Correspondence: ; Tel.: +36-52512900
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4
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Honcharenko D, Rocha CSJ, Lundin KE, Maity J, Milton S, Tedebark U, Murtola M, Honcharenko M, Slaitas A, Smith CIE, Zain R, Strömberg R. 2'- O-( N-(Aminoethyl)carbamoyl)methyl Modification Allows for Lower Phosphorothioate Content in Splice-Switching Oligonucleotides with Retained Activity. Nucleic Acid Ther 2022; 32:221-233. [PMID: 35238623 PMCID: PMC9221157 DOI: 10.1089/nat.2021.0086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
2′-O-(N-(Aminoethyl)carbamoyl)methyl (2′-O-AECM)-modified oligonucleotides (ONs) and their mixmers with 2′-O-methyl oligonucleotides (2′-OMe ONs) with phosphodiester linkers as well as with partial and full phosphorothioate (PS) inclusion were synthesized and functionally evaluated as splice-switching oligonucleotides in several different reporter cell lines originating from different tissues. This was enabled by first preparing the AECM-modified A, C, G and U, which required a different strategy for each building block. The AECM modification has previously been shown to provide high resistance to enzymatic degradation, even without PS linkages. It is therefore particularly interesting and unprecedented that the 2′-O-AECM ONs are shown to have efficient splice-switching activity even without inclusion of PS linkages and found to be as effective as 2′-OMe PS ONs. Importantly, the PS linkages can be partially included, without any significant reduction in splice-switching efficacy. This suggests that AECM modification has the potential to be used in balancing the PS content of ONs. Furthermore, conjugation of 2′-O-AECM ONs to an endosomal escape peptide significantly increased splice-switching suggesting that this effect could possibly be due to an increase in uptake of ON to the site of action.
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Affiliation(s)
- Dmytro Honcharenko
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Cristina S J Rocha
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden
| | - Karin E Lundin
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden
| | - Jyotirmoy Maity
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Stefan Milton
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Ulf Tedebark
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Merita Murtola
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | | | | | - C I Edvard Smith
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden
| | - Rula Zain
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden.,Department of Clinical Genetics, Center for Rare Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Roger Strömberg
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
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5
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Pham TC, Nguyen VN, Choi Y, Lee S, Yoon J. Recent Strategies to Develop Innovative Photosensitizers for Enhanced Photodynamic Therapy. Chem Rev 2021; 121:13454-13619. [PMID: 34582186 DOI: 10.1021/acs.chemrev.1c00381] [Citation(s) in RCA: 532] [Impact Index Per Article: 177.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This review presents a robust strategy to design photosensitizers (PSs) for various species. Photodynamic therapy (PDT) is a photochemical-based treatment approach that involves the use of light combined with a light-activated chemical, referred to as a PS. Attractively, PDT is one of the alternatives to conventional cancer treatment due to its noninvasive nature, high cure rates, and low side effects. PSs play an important factor in photoinduced reactive oxygen species (ROS) generation. Although the concept of photosensitizer-based photodynamic therapy has been widely adopted for clinical trials and bioimaging, until now, to our surprise, there has been no relevant review article on rational designs of organic PSs for PDT. Furthermore, most of published review articles in PDT focused on nanomaterials and nanotechnology based on traditional PSs. Therefore, this review aimed at reporting recent strategies to develop innovative organic photosensitizers for enhanced photodynamic therapy, with each example described in detail instead of providing only a general overview, as is typically done in previous reviews of PDT, to provide intuitive, vivid, and specific insights to the readers.
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Affiliation(s)
- Thanh Chung Pham
- Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan 48513, Korea
| | - Van-Nghia Nguyen
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 03760, Korea
| | - Yeonghwan Choi
- Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan 48513, Korea
| | - Songyi Lee
- Department of Chemistry, Pukyong National University, Busan 48513, Korea.,Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan 48513, Korea
| | - Juyoung Yoon
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 03760, Korea
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6
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Tsukamoto M, Oyama KI. Recent application of acidic 1,3-azolium salts as promoters in the solution-phase synthesis of nucleosides and nucleotides. Tetrahedron Lett 2018. [DOI: 10.1016/j.tetlet.2018.03.074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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7
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Weissman BP, Li NS, York D, Harris M, Piccirilli JA. Heavy atom labeled nucleotides for measurement of kinetic isotope effects. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1737-45. [PMID: 25828952 DOI: 10.1016/j.bbapap.2015.03.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/06/2015] [Accepted: 03/18/2015] [Indexed: 02/01/2023]
Abstract
Experimental analysis of kinetic isotope effects represents an extremely powerful approach for gaining information about the transition state structure of complex reactions not available through other methodologies. The implementation of this approach to the study of nucleic acid chemistry requires the synthesis of nucleobases and nucleotides enriched for heavy isotopes at specific positions. In this review, we highlight current approaches to the synthesis of nucleic acids enriched site specifically for heavy oxygen and nitrogen and their application in heavy atom isotope effect studies. This article is part of a special issue titled: Enzyme Transition States from Theory and Experiment.
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Affiliation(s)
| | - Nan-Sheng Li
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Darrin York
- Center for Integrative Proteomics Research, Biology at the Interface with the Mathematical and Physical Sciences (BioMaPS) Institute for Quantitative Biology, The State University of New Jersey, Piscataway, NJ, USA; Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Michael Harris
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Joseph A Piccirilli
- Department of Chemistry, University of Chicago, Chicago, IL, USA; Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA.
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8
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Mellal D, Fonvielle M, Santarem M, Chemama M, Schneider Y, Iannazzo L, Braud E, Arthur M, Etheve-Quelquejeu M. Synthesis and biological evaluation of non-isomerizable analogues of Ala-tRNAAla. Org Biomol Chem 2013; 11:6161-9. [DOI: 10.1039/c3ob41206g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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9
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A two-step chemical mechanism for ribosome-catalysed peptide bond formation. Nature 2011; 476:236-9. [PMID: 21765427 PMCID: PMC3154986 DOI: 10.1038/nature10248] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 06/03/2011] [Indexed: 01/18/2023]
Abstract
The chemical step of natural protein synthesis, peptide bond formation, is catalysed by the large subunit of the ribosome. Crystal structures have shown that the active site for peptide bond formation is composed entirely of RNA. Recent work has focused on how an RNA active site is able to catalyse this fundamental biological reaction at a suitable rate for protein synthesis. On the basis of the absence of important ribosomal functional groups, lack of a dependence on pH, and the dominant contribution of entropy to catalysis, it has been suggested that the role of the ribosome is limited to bringing the substrates into close proximity. Alternatively, the importance of the 2'-hydroxyl of the peptidyl-transfer RNA and a Brønsted coefficient near zero have been taken as evidence that the ribosome coordinates a proton-transfer network. Here we report the transition state of peptide bond formation, based on analysis of the kinetic isotope effect at five positions within the reaction centre of a peptidyl-transfer RNA mimic. Our results indicate that in contrast to the uncatalysed reaction, formation of the tetrahedral intermediate and proton transfer from the nucleophilic nitrogen both occur in the rate-limiting step. Unlike in previous proposals, the reaction is not fully concerted; instead, breakdown of the tetrahedral intermediate occurs in a separate fast step. This suggests that in addition to substrate positioning, the ribosome is contributing to chemical catalysis by changing the rate-limiting transition state.
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10
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Caron J, Lepeltier E, Reddy LH, Lepêtre-Mouelhi S, Wack S, Bourgaux C, Couvreur P, Desmaële D. Squalenoyl Gemcitabine Monophosphate: Synthesis, Characterisation of Nanoassemblies and Biological Evaluation. European J Org Chem 2011. [DOI: 10.1002/ejoc.201100036] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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11
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Rangelov MA, Petrova GP, Yomtova VM, Vayssilov GN. Catalytic Role of Vicinal OH in Ester Aminolysis: Proton Shuttle versus Hydrogen Bond Stabilization. J Org Chem 2010; 75:6782-92. [DOI: 10.1021/jo100886p] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Miroslav A. Rangelov
- Laboratory of BioCatalysis, Institute of Organic Chemistry, Bulgarian Academy of Sciences, Str. Acad. G. Bontchev, Bl. 9, 1113 Sofia, Bulgaria
| | - Galina P. Petrova
- Faculty of Chemistry, University of Sofia, Boulevard James Bouchier 1, 1164 Sofia, Bulgaria
| | - Vihra M. Yomtova
- Laboratory of BioCatalysis, Institute of Organic Chemistry, Bulgarian Academy of Sciences, Str. Acad. G. Bontchev, Bl. 9, 1113 Sofia, Bulgaria
| | - Georgi N. Vayssilov
- Faculty of Chemistry, University of Sofia, Boulevard James Bouchier 1, 1164 Sofia, Bulgaria
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12
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Rangelov MA, Petrova GP, Yomtova VM, Vayssilov GN. Hierarchical approach to conformational search and selection of computational method in modeling the mechanism of ester ammonolysis. J Mol Graph Model 2010; 29:246-55. [DOI: 10.1016/j.jmgm.2010.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2010] [Revised: 07/17/2010] [Accepted: 07/20/2010] [Indexed: 02/02/2023]
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13
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Hiller DA, Zhong M, Singh V, Strobel SA. Transition states of uncatalyzed hydrolysis and aminolysis reactions of a ribosomal P-site substrate determined by kinetic isotope effects. Biochemistry 2010; 49:3868-78. [PMID: 20359191 PMCID: PMC2864349 DOI: 10.1021/bi901458x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The ester bond of peptidyl-tRNA undergoes nucleophilic attack in solution and when catalyzed by the ribosome. To characterize the uncatalyzed hydrolysis reaction, a model of peptide release, the transition state structure for hydrolysis of a peptidyl-tRNA mimic was determined. Kinetic isotope effects were measured at several atoms that potentially undergo a change in bonding in the transition state. Large kinetic isotope effects of carbonyl (18)O and alpha-deuterium substitutions on uncatalyzed hydrolysis indicate the transition state is nearly tetrahedral. Kinetic isotope effects were also measured for aminolysis by hydroxylamine to study a reaction similar to the formation of a peptide bond. In contrast to hydrolysis, the large leaving group (18)O isotope effect indicates the C-O3' bond has undergone significant scission in the transition state. The smaller carbonyl (18)O and alpha-deuterium effects are consistent with a later transition state. The assay developed here can also be used to measure isotope effects for the ribosome-catalyzed reactions. These uncatalyzed reactions serve as a basis for determining what aspects of the transition states are stabilized by the ribosome to achieve a rate enhancement.
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Affiliation(s)
- David A Hiller
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven CT 06511 USA
| | | | - Vipender Singh
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven CT 06511 USA
| | - Scott A Strobel
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven CT 06511 USA
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14
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Caron J, Reddy LH, Lepêtre-Mouelhi S, Wack S, Clayette P, Rogez-Kreuz C, Yousfi R, Couvreur P, Desmaële D. Squalenoyl nucleoside monophosphate nanoassemblies: new prodrug strategy for the delivery of nucleotide analogues. Bioorg Med Chem Lett 2010; 20:2761-4. [PMID: 20363623 DOI: 10.1016/j.bmcl.2010.03.070] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 03/16/2010] [Accepted: 03/16/2010] [Indexed: 10/19/2022]
Abstract
4-(N)-1,1',2-trisnor-squalenoyldideoxycytidine monophosphate (SQddC-MP) and 4-(N)-1,1',2-trisnor-squalenoylgemcitabine monophosphate (SQdFdC-MP) were synthesized using phosphoramidite chemistry. These amphiphilic molecules self-assembled to about hundred nanometers size nanoassemblies in aqueous medium. Nanoassemblies of SQddC-MP displayed significant anti-HIV activity whereas SQdFdC-MP nanoassemblies displayed promising anticancer activity on leukemia cells. These results suggested that squalene conjugate of negatively charged nucleotide analogues efficiently penetrated within cells. Thus, we propose a new prodrug strategy for improved delivery of nucleoside analogues to ameliorate their biological efficacy.
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Affiliation(s)
- Joachim Caron
- Université Paris-Sud, Faculté de Pharmacie, UMR CNRS 8076, 5 rue J.-B. Clément, 92296 Châtenay-Malabry, France
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15
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Frederiksen JK, Piccirilli JA. Identification of catalytic metal ion ligands in ribozymes. Methods 2009; 49:148-66. [PMID: 19651216 DOI: 10.1016/j.ymeth.2009.07.005] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 07/20/2009] [Accepted: 07/29/2009] [Indexed: 01/05/2023] Open
Abstract
Site-bound metal ions participate in the catalytic mechanisms of many ribozymes. Understanding these mechanisms therefore requires knowledge of the specific ligands on both substrate and ribozyme that coordinate these catalytic metal ions. A number of different structural and biochemical strategies have been developed and refined for identifying metal ion binding sites within ribozymes, and for assessing the catalytic contributions of the metal ions bound at those sites. We review these approaches and provide examples of their application, focusing in particular on metal ion rescue experiments and their roles in the construction of the transition state models for the Tetrahymena group I and RNase P ribozymes.
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Affiliation(s)
- John K Frederiksen
- The Pritzker School of Medicine, The University of Chicago, Chicago, IL 60637, USA
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16
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Moroder H, Steger J, Graber D, Fauster K, Trappl K, Marquez V, Polacek N, Wilson D, Micura R. Non-Hydrolyzable RNA-Peptide Conjugates: A Powerful Advance in the Synthesis of Mimics for 3′-Peptidyl tRNA Termini. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200900939] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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17
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Moroder H, Steger J, Graber D, Fauster K, Trappl K, Marquez V, Polacek N, Wilson D, Micura R. Non-Hydrolyzable RNA-Peptide Conjugates: A Powerful Advance in the Synthesis of Mimics for 3′-Peptidyl tRNA Termini. Angew Chem Int Ed Engl 2009; 48:4056-60. [DOI: 10.1002/anie.200900939] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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18
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Harris ME, Cassano AG. Experimental analyses of the chemical dynamics of ribozyme catalysis. Curr Opin Chem Biol 2008; 12:626-39. [PMID: 18952193 DOI: 10.1016/j.cbpa.2008.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2008] [Revised: 10/13/2008] [Accepted: 10/13/2008] [Indexed: 11/30/2022]
Abstract
Most ribozymes in Nature catalyze alcoholysis or hydrolysis of RNA phosphodiester bonds. Studies of the corresponding non-enzymatic reactions reveal a complex mechanistic landscape allowing for a variety of transition states and both concerted and stepwise mechanisms. High-resolution structures, incisive biochemical studies and computer simulations are providing glimpses into how ribozyme catalyzed reactions traverse this landscape. However, direct experimental tests of mechanistic detail at the chemical level are not easily achieved. Kinetic isotope effects (KIEs) probe directly the differences in the vibrational 'environment' of the atoms undergoing chemical transformation on going from the ground state to the transition state. Thus, KIEs can in principle provide direct information about transition state bonding and so may be instrumental in evaluating possible transition states for ribozyme catalyzed reactions. Understanding charge distribution in the transition state may help resolve how rate acceleration is accomplished and perhaps the similarities and differences in how RNA and protein active sites operate. Several barriers to successful application of KIE analysis to ribozymes have recently been overcome, and new chemical details are beginning to emerge.
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Affiliation(s)
- Michael E Harris
- RNA Center and Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH 44118, USA.
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