1
|
Das G, Harikrishna S, Gore KR. Investigating the Effect of Chemical Modifications on the Ribose Sugar Conformation, Watson-Crick Base Pairing, and Intrastrand Stacking Interactions: A Theoretical Approach. J Phys Chem B 2024; 128:8313-8331. [PMID: 39172066 DOI: 10.1021/acs.jpcb.4c02557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2024]
Abstract
Over the last few decades, chemically modified sugars have been incorporated into nucleic acid-based therapeutics to improve their pharmacological potential. Chemical modification can influence the sugar conformation, Watson-Crick hydrogen (W-C) bonding, and nucleobase stacking interactions, which play major roles in the structural integrity and dynamic properties of nucleic acid duplexes. In this study, we categorized 33 uridine (U*) and cytidine (C*) sugar modifications and calculated their sugar conformational parameters. We also calculated the Watson-Crick hydrogen bond energies of the modified RNA-type base pairs (U*:A and C*:G) using DFT and sSAPT0 methods. The W-C base pairing energy calculations suggested that the South-type modified sugar strengthens the C*:G base pair and weakens the U*:A base pair compared to the unmodified one. In contrast, the North-type sugar modifications form weaker C*:G base pair and marginally stronger U*:A base pair compared to the South-type modified sugars. Moreover, intrastrand base stacking energies were calculated for 15 modifications incorporated at the fourth position in 7-mer non-self-complementary RNA duplexes [(GCAU*GAC)2 and (GCAC*GAC)2], utilizing molecular dynamics simulation and quantum mechanical (DFT and sSAPT0) methods. The sugar modifications were found to have minimal effect on the intrastrand base-stacking interactions. However, the glycol nucleic acid modification disturbs the intrastrand base-stacking significantly, corroborating the experimental data.
Collapse
Affiliation(s)
- Gourav Das
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - S Harikrishna
- Department of Chemistry and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Kiran R Gore
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| |
Collapse
|
2
|
Li Q, Dong M, Chen P. Advances in structural-guided modifications of siRNA. Bioorg Med Chem 2024; 110:117825. [PMID: 38954918 DOI: 10.1016/j.bmc.2024.117825] [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: 05/16/2024] [Revised: 06/27/2024] [Accepted: 06/27/2024] [Indexed: 07/04/2024]
Abstract
To date, the US Food and Drug Administration (FDA) has approved six small interfering RNA (siRNA) drugs: patisiran, givosiran, lumasiran, inclisiran, vutrisiran, and nedosiran, serving as compelling evidence of the promising potential of RNA interference (RNAi) therapeutics. The successful implementation of siRNA therapeutics is improved through a combination of various chemical modifications and diverse delivery approaches. The utilization of chemically modified siRNA at specific sites on either the sense strand (SS) or antisense strand (AS) has the potential to enhance resistance to ribozyme degradation, improve stability and specificity, and prolong the efficacy of drugs. Herein, we provide comprehensive analyses concerning the correlation between chemical modifications and structure-guided siRNA design. Various modifications, such as 2'-modifications, 2',4'-dual modifications, non-canonical sugar modifications, and phosphonate mimics, are crucial for the activity of siRNA. We also emphasize the essential strategies for enhancing overhang stability, improving RISC loading efficacy and strand selection, reducing off-target effects, and discussing the future of targeted delivery.
Collapse
Affiliation(s)
- Qiang Li
- Department of Medicinal Chemistry, School of Pharmacy, Qingdao University, Qingdao 266021, China; Research and Development Department, NanoPeptide (Qingdao) Biotechnology Ltd., Qingdao, China.
| | - Mingxin Dong
- Department of Medicinal Chemistry, School of Pharmacy, Qingdao University, Qingdao 266021, China.
| | - Pu Chen
- Research and Development Department, NanoPeptide (Qingdao) Biotechnology Ltd., Qingdao, China; Department of Chemical Engineering and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON, Canada.
| |
Collapse
|
3
|
Novikova D, Sagaidak A, Vorona S, Tribulovich V. A Visual Compendium of Principal Modifications within the Nucleic Acid Sugar Phosphate Backbone. Molecules 2024; 29:3025. [PMID: 38998973 PMCID: PMC11243533 DOI: 10.3390/molecules29133025] [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: 04/22/2024] [Revised: 06/21/2024] [Accepted: 06/24/2024] [Indexed: 07/14/2024] Open
Abstract
Nucleic acid chemistry is a huge research area that has received new impetus due to the recent explosive success of oligonucleotide therapy. In order for an oligonucleotide to become clinically effective, its monomeric parts are subjected to modifications. Although a large number of redesigned natural nucleic acids have been proposed in recent years, the vast majority of them are combinations of simple modifications proposed over the past 50 years. This review is devoted to the main modifications of the sugar phosphate backbone of natural nucleic acids known to date. Here, we propose a systematization of existing knowledge about modifications of nucleic acid monomers and an acceptable classification from the point of view of chemical logic. The visual representation is intended to inspire researchers to create a new type of modification or an original combination of known modifications that will produce unique oligonucleotides with valuable characteristics.
Collapse
Affiliation(s)
- Daria Novikova
- Laboratory of Molecular Pharmacology, St. Petersburg State Institute of Technology, St. Petersburg 190013, Russia
| | - Aleksandra Sagaidak
- Laboratory of Molecular Pharmacology, St. Petersburg State Institute of Technology, St. Petersburg 190013, Russia
| | - Svetlana Vorona
- Laboratory of Molecular Pharmacology, St. Petersburg State Institute of Technology, St. Petersburg 190013, Russia
| | - Vyacheslav Tribulovich
- Laboratory of Molecular Pharmacology, St. Petersburg State Institute of Technology, St. Petersburg 190013, Russia
| |
Collapse
|
4
|
Goyon A, Blevins MS, Napolitano JG, Nguyen D, Goel M, Scott B, Wang J, Koenig SG, Chen T, Zhang K. Characterization of antisense oligonucleotide and guide ribonucleic acid diastereomers by hydrophilic interaction liquid chromatography coupled to mass spectrometry. J Chromatogr A 2023; 1708:464327. [PMID: 37660562 DOI: 10.1016/j.chroma.2023.464327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/21/2023] [Accepted: 08/23/2023] [Indexed: 09/05/2023]
Abstract
Oligonucleotides have become an essential modality for a variety of therapeutic approaches, including cell and gene therapies. Rapid progress in the field has attracted significant research in designing novel oligonucleotide chemistries and structures. Beyond their polar nature, the length of large RNAs and presence of numerous diastereomers for phosphorothioate (PS)-modified RNAs pose heightened challenges for their characterization. In this study, the stereochemistry of a fully-modified antisense oligonucleotide (ASO) and partially-modified guide RNAs (gRNAs) was investigated using HILIC and orthogonal techniques. The profiles of three lots of a fully-modified ASO with PS linkages were compared using ion-pairing RPLC (IPRP) and HILIC. Interestingly, three isomer peaks were partially resolved by HILIC for two lots while only one peak was observed on the IPRP profile. Model oligonucleotides having the same sequence of the five nucleotides incorporated to the 3'-end of the gRNA but differing in their number and position of PS linkages were investigated by HILIC, IPRP, ion mobility spectrometry-mass spectrometry (IM-MS) and nuclear magnetic resonance (NMR). An strategy was ultimately designed to aid in the characterization of gRNA stereochemistry. Ribonuclease (RNase) T1 digestion enabled the characterization of gRNA diastereomers by reducing their number from 32 at the gRNA intact level to 4 or 8 at the fragment level. To our knowledge, this is the first time that HILIC has successfully been utilized for the profiling of diastereomers for various oligonucleotide formats and chemical modifications.
Collapse
Affiliation(s)
- Alexandre Goyon
- Synthetic Molecule Pharmaceutical Sciences, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA.
| | - Molly S Blevins
- Synthetic Molecule Pharmaceutical Sciences, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - José G Napolitano
- Synthetic Molecule Pharmaceutical Sciences, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Daniel Nguyen
- Synthetic Molecule Pharmaceutical Sciences, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Meenakshi Goel
- Synthetic Molecule Pharmaceutical Sciences, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Brandon Scott
- Synthetic Molecule Pharmaceutical Sciences, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Jenny Wang
- Synthetic Molecule Pharmaceutical Sciences, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Stefan G Koenig
- Synthetic Molecule Pharmaceutical Sciences, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Tao Chen
- Synthetic Molecule Pharmaceutical Sciences, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Kelly Zhang
- Synthetic Molecule Pharmaceutical Sciences, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA.
| |
Collapse
|
5
|
Martínez-Montero S, Rajwanshi VK, Pandey RK, De Costa NTS, Hong J, Beigelman L, Gryaznov SM, Pourshahian S. New Oligonucleotide 2'-O-Alkyl N3'→P5' (Thio)-Phosphoramidates as Potent Antisense Agents: Physicochemical Properties and Biological Activity. Nucleic Acid Ther 2023; 33:319-328. [PMID: 37638793 DOI: 10.1089/nat.2023.0014] [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] [Indexed: 08/29/2023] Open
Abstract
We describe here the design, synthesis, physicochemical properties, and hepatitis B antiviral activity of new 2'-O-alkyl ribonucleotide N3'→P5' phosphoramidate (2'-O-alkyl-NPO) and (thio)-phosphoramidite (2'-O-alkyl-NPS) oligonucleotide analogs. Oligonucleotides with different 2'-O-alkyl modifications such as 2'-O-methyl, -O-ethyl, -O-allyl, and -O-methoxyethyl combined with 3'-amino sugar-phosphate backbone were synthesized and evaluated. These molecules form stable duplexes with complementary DNA and RNA strands. They show an increase in duplex melting temperatures of up to 2.5°C and 4°C per linkage, respectively, compared to unmodified DNA. The results agree with predominantly C3'-endo sugar pucker conformation. Moreover, 2'-O-alkyl phosphoramidites demonstrate higher hydrolytic stability at pH 5.5 than 2'-deoxy NPOs. In addition, the relative lipophilicity of the 2'-O-alkyl-NPO and NPS oligonucleotides is higher than that of their 3'-O- counterparts. The 2'-O-alkyl-NPS oligonucleotides were evaluated as antisense (ASO) compounds in vitro and in vivo using Hepatitis B virus as a model system. Subcutaneous delivery of GalNAc conjugated 2'-O-MOE-NPS gapmers demonstrated higher activity than the 3'-O-containing 2'-O-MOE counterpart. The properties of 2'-O-alkyl-NPS constructs make them attractive candidates as ASO suitable for further evaluation and development.
Collapse
Affiliation(s)
- Saúl Martínez-Montero
- Janssen Pharmaceutical Companies of Johnson and Johnson, South San Francisco, California, USA
| | - Vivek K Rajwanshi
- Janssen Pharmaceutical Companies of Johnson and Johnson, South San Francisco, California, USA
| | - Rajendra K Pandey
- Janssen Pharmaceutical Companies of Johnson and Johnson, South San Francisco, California, USA
| | - N Tilani S De Costa
- Janssen Pharmaceutical Companies of Johnson and Johnson, South San Francisco, California, USA
| | - Jin Hong
- Janssen Pharmaceutical Companies of Johnson and Johnson, South San Francisco, California, USA
| | - Leonid Beigelman
- Janssen Pharmaceutical Companies of Johnson and Johnson, South San Francisco, California, USA
| | - Sergei M Gryaznov
- Janssen Pharmaceutical Companies of Johnson and Johnson, South San Francisco, California, USA
| | - Soheil Pourshahian
- Janssen Pharmaceutical Companies of Johnson and Johnson, South San Francisco, California, USA
| |
Collapse
|
6
|
Sato H, Chandela A, Ueno Y. Synthesis and characterization of novel (S)-5'-C-aminopropyl-2'-fluorouridine modified oligonucleotides as therapeutic siRNAs. Bioorg Med Chem 2023; 87:117317. [PMID: 37196425 DOI: 10.1016/j.bmc.2023.117317] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/04/2023] [Accepted: 05/04/2023] [Indexed: 05/19/2023]
Abstract
The lack of stability of natural nucleosides limits their application in small interfering RNA (siRNA)-mediated RNA interference (RNAi). Various chemical modifications have been reported to improve their pharmacokinetic behavior; however, the development of potential candidates is still underway. In this study, we designed and synthesized (S)-5'-C-aminopropyl-2'-fluorouridine (5'-AP-2'-FU) and evaluated the properties of siRNAs containing this analog. A comparative thermodynamic study revealed the enhanced thermal stability of double-stranded RNAs (dsRNAs) containing 5'-AP-2'-FU in a position-specific manner, whereas (S)-5'-C-aminopropyl-2'-O-methyluridine (5'-AP-2'-MoU)-modified dsRNAs exhibited lower melting temperatures. This improved thermal stability of RNA duplexes is attributed to favorable entropy loss, which induces the duplex into an N-type (C3'-endo) conformation and enhances duplex binding in this case. The 5'-AP-2'-FU analog was also suitable for incorporation into the passenger strand to induce gene-silencing activity. Gene knockdown efficacy was comparable to that of unmodified siRNAs, and the best response was observed by introducing 5'-AP-2'-FU near the 3'-terminal end of the passenger strand. In addition, the single-stranded RNAs (ssRNAs) modified with 5'-AP-2'-FU showed strong resistance against decomposition by nucleases when treated with buffer containing bovine serum, which was similar to 5'-AP-2'-MoU.
Collapse
Affiliation(s)
- Hitotaka Sato
- United Graduate School of Agricultural Science, Gifu University, Japan
| | - Akash Chandela
- Course of Applied Life Science, Faculty of Applied Biological Sciences, Gifu University, Japan
| | - Yoshihito Ueno
- Department of Life Science and Chemistry, Graduate School of Natural Science and Technology, Gifu University, Japan; Course of Applied Life Science, Faculty of Applied Biological Sciences, Gifu University, Japan; United Graduate School of Agricultural Science, Gifu University, Japan; Center for One Medicine Innovative Translational Research (COMIT), Gifu University Institute for Advanced Study, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
| |
Collapse
|
7
|
Lowe PT, O'Hagan D. 4'-Fluoro-nucleosides and nucleotides: from nucleocidin to an emerging class of therapeutics. Chem Soc Rev 2023; 52:248-276. [PMID: 36472161 DOI: 10.1039/d2cs00762b] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The history and development of 4'-fluoro-nucleosides is discussed in this review. This is a class of nucleosides which have their origin in the discovery of the rare fluorine containing natural product nucleocidin. Nucleocidin contains a fluorine atom located at the 4'-position of its ribose ring. From its early isolation as an unexpected natural product, to its total synthesis and bioactivity assessment, nucleocidin has played a role in inspiring the exploration of 4'-fluoro-nucleosides as a privileged motif for nucleoside-based therapeutics.
Collapse
Affiliation(s)
- Phillip T Lowe
- School of Chemistry and Biomedical Sciences Research Centre, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK.
| | - David O'Hagan
- School of Chemistry and Biomedical Sciences Research Centre, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK.
| |
Collapse
|
8
|
Das G, Harikrishna S, Gore KR. Influence of Sugar Modifications on the Nucleoside Conformation and Oligonucleotide Stability: A Critical Review. CHEM REC 2022; 22:e202200174. [PMID: 36048010 DOI: 10.1002/tcr.202200174] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/16/2022] [Indexed: 12/15/2022]
Abstract
Ribofuranose sugar conformation plays an important role in the structure and dynamics of functional nucleic acids such as siRNAs, AONs, aptamers, miRNAs, etc. To improve their therapeutic potential, several chemical modifications have been introduced into the sugar moiety over the years. The stability of the oligonucleotide duplexes as well as the formation of stable and functional protein-oligonucleotide complexes are dictated by the conformation and dynamics of the sugar moiety. In this review, we systematically categorise various ribofuranose sugar modifications employed in DNAs and RNAs so far. We discuss different stereoelectronic effects imparted by different substituents on the sugar ring and how these effects control sugar puckering. Using this data, it would be possible to predict the precise use of chemical modifications and design novel sugar-modified nucleosides for therapeutic oligonucleotides that can improve their physicochemical properties.
Collapse
Affiliation(s)
- Gourav Das
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal-721302, India
| | - S Harikrishna
- Department of Chemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Kiran R Gore
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal-721302, India
| |
Collapse
|
9
|
Kusaka S, Yamamoto K, Shinohara M, Minato Y, Ichikawa S. Design, synthesis and conformation-activity relationship analysis of LNA/BNA-type 5'-O-aminoribosyluridine as MraY inhibitors. Bioorg Med Chem 2022; 65:116744. [PMID: 35500521 DOI: 10.1016/j.bmc.2022.116744] [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: 03/17/2022] [Revised: 04/03/2022] [Accepted: 04/05/2022] [Indexed: 11/02/2022]
Abstract
It is important to understand and control the biologically active conformation in medicinal chemistry. Muraymycins and caprazamycins, which are strong inhibitors of MraY, are promising antibacterial agents with a novel mode of action. Focusing on a sugar puckering and a dihedral angle ϕ of the uridine moiety of these natural products, LNA/BNA-type 5'-O-aminoribosyluridine analogues, whose puckering of the ribose moiety are completely restricted to the N-type, were designed and synthesized as simplified MraY inhibitors. Their conformation-activity relationship was further investigated in details. The conformation-activity relationship analysis investigated in this study could be a general guideline for simplification and rational drug design of MraY inhibitory nucleoside natural products.
Collapse
Affiliation(s)
- Shintaro Kusaka
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan
| | - Kazuki Yamamoto
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan
| | - Motoko Shinohara
- Department of Microbiology, Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi, 470-1192, Japan
| | - Yusuke Minato
- Department of Microbiology, Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi, 470-1192, Japan
| | - Satoshi Ichikawa
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan; Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan; Global Station for Biosurfaces and Drug Discovery, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan.
| |
Collapse
|
10
|
Katsuzaki Y, Tsukimura R, Chandela A, Chano T, Ueno Y. 4'-C-Aminoethoxy-Modified DNAs Exhibit Increased Nuclease Resistance, Sustained RNase H Activity, and Inhibition of KRAS Gene Expression. Chem Biodivers 2022; 19:e202200125. [PMID: 35773240 DOI: 10.1002/cbdv.202200125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 06/17/2022] [Indexed: 11/09/2022]
Abstract
The linear synthesis of 4'-C-aminoethoxy thymidine (AEoT) nucleoside phosphoramidite was accomplished using deoxythymidine as the starting material. This analog was incorporated into several oligonucleotides, the applicability of which as antisense oligonucleotides (ASOs) was then evaluated. The AEoT-modified DNA/RNA duplex exhibited improved thermal stability compared to unmodified and 4'-C-aminoethyl thymidine (4'-AET) modified heteroduplexes. The serum stability of AEoT-modified DNA was notably increased by several-folds compared to that of unmodified DNA. Furthermore, RNase H-dependent cleavage of the modified-DNA/RNA hybrids was found to be sustained. In addition, the modified antisense and unmodified oligonucleotides also displayed relatively comparable inhibition of the KRAS gene in human lung cancer cells. This study strengthens our understanding of the potential application of 4'-C-aminoethoxy-modified nucleotides as ASO therapeutics.
Collapse
Affiliation(s)
- Yuki Katsuzaki
- Department of Life Science and Chemistry, Graduate School of Natural Science and Technology, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Ryo Tsukimura
- Department of Life Science and Chemistry, Graduate School of Natural Science and Technology, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Akash Chandela
- Faculty of Applied Biological Sciences, Gifu University, Japan
| | - Tokuhiro Chano
- Department of Medical Genetics, Shiga University of Medical, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan
| | - Yoshihito Ueno
- Department of Life Science and Chemistry, Graduate School of Natural Science and Technology, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.,Faculty of Applied Biological Sciences, Gifu University, Japan.,Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, Japan
| |
Collapse
|
11
|
Shet H, Sahu R, Sanghvi YS, Kapdi AR. Strategies for the Synthesis of Fluorinated Nucleosides, Nucleotides and Oligonucleotides. CHEM REC 2022; 22:e202200066. [PMID: 35638251 DOI: 10.1002/tcr.202200066] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/11/2022] [Indexed: 11/09/2022]
Abstract
Fluorinated nucleosides and oligonucleotides are of specific interest as probes for studying nucleic acids interaction, structures, biological transformations, and its biomedical applications. Among various modifications of oligonucleotides, fluorination of preformed nucleoside and/or nucleotides have recently gained attention owing to the unique properties of fluorine atoms imparting medicinal properties with respect to the small size, electronegativity, lipophilicity, and ability for stereochemical control. This review deals with synthetic protocols for selective fluorination either at sugar or base moiety in a preformed nucleosides, nucleotides and nucleic acids using specific fluorinating reagents.
Collapse
Affiliation(s)
- Harshita Shet
- Department of Chemistry, Institute of Chemical Technology -, Indian Oil Odisha Campus, IIT Kharagpur Extension Centre, Mouza Samantpuri, Bhubaneswar, Odisha-751013, India.,Department of Chemistry, Institute of Chemical Technology, Nathalal Parekh road, Matunga, Mumbai-400019, India
| | - Rajesh Sahu
- Department of Chemistry, Institute of Chemical Technology, Nathalal Parekh road, Matunga, Mumbai-400019, India
| | - Yogesh S Sanghvi
- Rasayan Inc., 2802, Crystal Ridge, Encinitas, CA92024-6615, California, USA
| | - Anant R Kapdi
- Department of Chemistry, Institute of Chemical Technology, Nathalal Parekh road, Matunga, Mumbai-400019, India
| |
Collapse
|
12
|
Kajino R, Sakamoto S, Ueno Y. Synthesis, gene silencing activity, thermal stability, and serum stability of siRNA containing four ( S)-5'- C-aminopropyl-2'- O-methylnucleosides (A, adenosine; U, uridine; G, guanosine; and C, cytidine). RSC Adv 2022; 12:11454-11476. [PMID: 35425057 PMCID: PMC9002251 DOI: 10.1039/d2ra00705c] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 03/30/2022] [Indexed: 11/29/2022] Open
Abstract
Herein, we report the synthesis of (S)-5'-C-aminopropyl-2'-O-methyladenosine and (S)-5'-C-aminopropyl-2'-O-methylguanosine phosphoramidites and the properties of small interfering RNAs (siRNAs) containing four (S)-5'-C-aminopropyl-2'-O-methylnucleosides (A, adenosine; U, uridine; G, guanosine; and C, cytidine). The siRNAs containing (S)-5'-C-aminopropyl-nucleosides at the 3'- and 5'-regions of the passenger strand were well tolerated for RNA interference (RNAi) activity. Conversely, the (S)-5'-C-aminopropyl modification in the central region of the passenger strand decreased the RNAi activity. Furthermore, the siRNAs containing three or four consecutive (S)-5'-C-aminopropyl-2'-O-methylnucleosides at the 3'- and 5'-regions of the passenger strand exhibited RNAi activity similar to that of the corresponding 2'-O-methyl-modified siRNAs. Finally, it was observed that (S)-5'-C-aminopropyl modifications effectively improved the serum stability of the siRNAs, compared with 2'-O-methyl modifications. Therefore, (S)-5'-C-aminopropyl-2'-O-methylnucleosides would be useful for improving the serum stability of therapeutic siRNA molecules without affecting their RNAi activities.
Collapse
Affiliation(s)
- Ryohei Kajino
- United Graduate School of Agricultural Science, Gifu University Japan +81-58-293-2919 +81-58-293-2919
| | - Shuichi Sakamoto
- Institute of Microbial Chemistry (BIKAKEN) Numazu Branch, Microbial Chemistry Research Foundation 18-24 Miyamoto Numazu Shizuoka 410-0301 Japan
| | - Yoshihito Ueno
- United Graduate School of Agricultural Science, Gifu University Japan +81-58-293-2919 +81-58-293-2919
- Department of Life Science and Chemistry, The Graduate School of Natural Science and Technology, Gifu University Japan
- Course of Applied Life Science, Faculty of Applied Biological Sciences, Gifu University Japan
- Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University 1-1 Yanagido Gifu 501-1193 Japan
| |
Collapse
|
13
|
Ribosomal RNA 2'- O-methylations regulate translation by impacting ribosome dynamics. Proc Natl Acad Sci U S A 2022; 119:e2117334119. [PMID: 35294285 PMCID: PMC8944910 DOI: 10.1073/pnas.2117334119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
SignificanceThe presence of RNA chemical modifications has long been known, but their precise molecular consequences remain unknown. 2'-O-methylation is an abundant modification that exists in RNA in all domains of life. Ribosomal RNA (rRNA) represents a functionally important RNA that is heavily modified by 2'-O-methylations. Although abundant at functionally important regions of the rRNA, the contribution of 2'-O-methylations to ribosome activities is unknown. By establishing a method to disturb rRNA 2'-O-methylation patterns, we show that rRNA 2'-O-methylations affect the function and fidelity of the ribosome and change the balance between different ribosome conformational states. Our work links 2'-O-methylation to ribosome dynamics and defines a set of critical rRNA 2'-O-methylations required for ribosome biogenesis and others that are dispensable.
Collapse
|
14
|
Jones SP, Goossen C, Lewis SD, Delaney AM, Gleghorn ML. Not making the cut: Techniques to prevent RNA cleavage in structural studies of RNase-RNA complexes. J Struct Biol X 2022; 6:100066. [PMID: 35340590 PMCID: PMC8943300 DOI: 10.1016/j.yjsbx.2022.100066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 03/04/2022] [Indexed: 11/16/2022] Open
Abstract
RNases are varied in the RNA structures and sequences they target for cleavage and are an important type of enzyme in cells. Despite the numerous examples of RNases known, and of those with determined three-dimensional structures, relatively few examples exist with the RNase bound to intact cognate RNA substrate prior to cleavage. To better understand RNase structure and sequence specificity for RNA targets, in vitro methods used to assemble these enzyme complexes trapped in a pre-cleaved state have been developed for a number of different RNases. We have surveyed the Protein Data Bank for such structures and in this review detail methodologies that have successfully been used and relate them to the corresponding structures. We also offer ideas and suggestions for future method development. Many strategies within this review can be used in combination with X-ray crystallography, as well as cryo-EM, and other structure-solving techniques. Our hope is that this review will be used as a guide to resolve future yet-to-be-determined RNase-substrate complex structures.
Collapse
Affiliation(s)
- Seth P. Jones
- School of Chemistry and Materials Science, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623-5603, United States
| | - Christian Goossen
- School of Chemistry and Materials Science, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623-5603, United States
- Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Lothrop St, Pittsburgh, PA 15261, United States
| | - Sean D. Lewis
- School of Chemistry and Materials Science, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623-5603, United States
- Mayo Clinic, 200 1st St SW, Rochester, MN 5590, United States
| | - Annie M. Delaney
- School of Chemistry and Materials Science, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623-5603, United States
| | - Michael L. Gleghorn
- School of Chemistry and Materials Science, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623-5603, United States
| |
Collapse
|
15
|
Jana SK, Harikrishna S, Sudhakar S, El-Khoury R, Pradeepkumar PI, Damha MJ. Nucleoside Analogues with a Seven-Membered Sugar Ring: Synthesis and Structural Compatibility in DNA-RNA Hybrids. J Org Chem 2022; 87:2367-2379. [PMID: 35133166 DOI: 10.1021/acs.joc.1c02254] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein we describe results on the pairing properties of synthetic DNA and RNA oligonucleotides that contain nucleotide analogues with a 7-membered sugar ring (oxepane nucleotides). Specifically, we describe the stereoselective synthesis of a set of three oxepane thymine nucleosides (OxT), their conversion to phosphoramidite derivatives, and their use in solid-phase synthesis to yield chimeric OxT-DNA and OxT-RNA strands. The different regioisomeric OxT phosphoramidites allowed for positional variations of the phosphate bridge and assessment of duplex stability when the oxepane nucleotides were incorporated in dsDNA, dsRNA, and DNA-RNA hybrids. Little to no destabilization was observed when two of the three regioisomeric OxT units were incorporated in the DNA strand of DNA-RNA hybrids, a remarkable result considering the dramatically different structure of oxepanes in comparison to 2'-deoxynucleosides. Extensive molecular modeling and dynamics studies further revealed the various structural features responsible for the tolerance of both OxT modifications in DNA-RNA duplexes, such as base-base stacking and sugar-phosphate H-bond interactions. These studies suggest that oxepane nucleotide analogues may find applications in synthetic biology, where synthetic oligonucleotides can be used to create new tools for biotechnology and medicine.
Collapse
Affiliation(s)
- Sunit Kumar Jana
- Department of Chemistry, McGill University, 801 Sherbrooke St. West, Montreal, QC H3A 0B8, Canada
| | - S Harikrishna
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Sruthi Sudhakar
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Roberto El-Khoury
- Department of Chemistry, McGill University, 801 Sherbrooke St. West, Montreal, QC H3A 0B8, Canada
| | - P I Pradeepkumar
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Masad J Damha
- Department of Chemistry, McGill University, 801 Sherbrooke St. West, Montreal, QC H3A 0B8, Canada
| |
Collapse
|
16
|
Ding D, Zhou L, Giurgiu C, Szostak JW. Kinetic explanations for the sequence biases observed in the nonenzymatic copying of RNA templates. Nucleic Acids Res 2021; 50:35-45. [PMID: 34893864 PMCID: PMC8754633 DOI: 10.1093/nar/gkab1202] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/17/2021] [Accepted: 12/08/2021] [Indexed: 11/15/2022] Open
Abstract
The identification of nonenzymatic pathways for nucleic acid replication is a key challenge in understanding the origin of life. We have previously shown that nonenzymatic RNA primer extension using 2-aminoimidazole (2AI) activated nucleotides occurs primarily through an imidazolium-bridged dinucleotide intermediate. The reactive nature and preorganized structure of the intermediate increase the efficiency of primer extension but remain insufficient to drive extensive copying of RNA templates containing all four canonical nucleotides. To understand the factors that limit RNA copying, we synthesized all ten 2AI-bridged dinucleotide intermediates and measured the kinetics of primer extension in a model system. The affinities of the ten dinucleotides for the primer/template/helper complexes vary by over 7,000-fold, consistent with nearest neighbor energetic predictions. Surprisingly, the reaction rates at saturating intermediate concentrations still vary by over 15-fold, with the most weakly binding dinucleotides exhibiting a lower maximal reaction rate. Certain noncanonical nucleotides can decrease sequence dependent differences in affinity and primer extension rate, while monomers bridged to short oligonucleotides exhibit enhanced binding and reaction rates. We suggest that more uniform binding and reactivity of imidazolium-bridged intermediates may lead to the ability to copy arbitrary template sequences under prebiotically plausible conditions.
Collapse
Affiliation(s)
- Dian Ding
- Howard Hughes Medical Institute, Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, USA.,Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA
| | - Lijun Zhou
- Howard Hughes Medical Institute, Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, USA.,Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA
| | - Constantin Giurgiu
- Howard Hughes Medical Institute, Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, USA.,Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA
| | - Jack W Szostak
- Howard Hughes Medical Institute, Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, USA.,Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.,Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA
| |
Collapse
|
17
|
Liczner C, Duke K, Juneau G, Egli M, Wilds CJ. Beyond ribose and phosphate: Selected nucleic acid modifications for structure-function investigations and therapeutic applications. Beilstein J Org Chem 2021; 17:908-931. [PMID: 33981365 PMCID: PMC8093555 DOI: 10.3762/bjoc.17.76] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/14/2021] [Indexed: 12/16/2022] Open
Abstract
Over the past 25 years, the acceleration of achievements in the development of oligonucleotide-based therapeutics has resulted in numerous new drugs making it to the market for the treatment of various diseases. Oligonucleotides with alterations to their scaffold, prepared with modified nucleosides and solid-phase synthesis, have yielded molecules with interesting biophysical properties that bind to their targets and are tolerated by the cellular machinery to elicit a therapeutic outcome. Structural techniques, such as crystallography, have provided insights to rationalize numerous properties including binding affinity, nuclease stability, and trends observed in the gene silencing. In this review, we discuss the chemistry, biophysical, and structural properties of a number of chemically modified oligonucleotides that have been explored for gene silencing.
Collapse
Affiliation(s)
- Christopher Liczner
- Department of Chemistry and Biochemistry, Concordia University, Montréal, Québec H4B 1R6, Canada
| | - Kieran Duke
- Department of Chemistry and Biochemistry, Concordia University, Montréal, Québec H4B 1R6, Canada
| | - Gabrielle Juneau
- Department of Chemistry and Biochemistry, Concordia University, Montréal, Québec H4B 1R6, Canada
| | - Martin Egli
- Department of Biochemistry, Vanderbilt Institute of Chemical Biology, and Center for Structural Biology, School of Medicine, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Christopher J Wilds
- Department of Chemistry and Biochemistry, Concordia University, Montréal, Québec H4B 1R6, Canada
| |
Collapse
|
18
|
Akabane-Nakata M, Erande ND, Kumar P, Degaonkar R, Gilbert JA, Qin J, Mendez M, Woods LB, Jiang Y, Janas M, O’Flaherty DK, Zlatev I, Schlegel M, Matsuda S, Egli M, Manoharan M. siRNAs containing 2'-fluorinated Northern-methanocarbacyclic (2'-F-NMC) nucleotides: in vitro and in vivo RNAi activity and inability of mitochondrial polymerases to incorporate 2'-F-NMC NTPs. Nucleic Acids Res 2021; 49:2435-2449. [PMID: 33577685 PMCID: PMC7969009 DOI: 10.1093/nar/gkab050] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 01/13/2021] [Accepted: 02/07/2021] [Indexed: 02/01/2023] Open
Abstract
We recently reported the synthesis of 2'-fluorinated Northern-methanocarbacyclic (2'-F-NMC) nucleotides, which are based on a bicyclo[3.1.0]hexane scaffold. Here, we analyzed RNAi-mediated gene silencing activity in cell culture and demonstrated that a single incorporation of 2'-F-NMC within the guide or passenger strand of the tri-N-acetylgalactosamine-conjugated siRNA targeting mouse Ttr was generally well tolerated. Exceptions were incorporation of 2'-F-NMC into the guide strand at positions 1 and 2, which resulted in a loss of the in vitro activity. Activity at position 1 was recovered when the guide strand was modified with a 5' phosphate, suggesting that the 2'-F-NMC is a poor substrate for 5' kinases. In mice, the 2'-F-NMC-modified siRNAs had comparable RNAi potencies to the parent siRNA. 2'-F-NMC residues in the guide seed region position 7 and at positions 10, 11 and 12 were well tolerated. Surprisingly, when the 5'-phosphate mimic 5'-(E)-vinylphosphonate was attached to the 2'-F-NMC at the position 1 of the guide strand, activity was considerably reduced. The steric constraints of the bicyclic 2'-F-NMC may impair formation of hydrogen-bonding interactions between the vinylphosphonate and the MID domain of Ago2. Molecular modeling studies explain the position- and conformation-dependent RNAi-mediated gene silencing activity of 2'-F-NMC. Finally, the 5'-triphosphate of 2'-F-NMC is not a substrate for mitochondrial RNA and DNA polymerases, indicating that metabolites should not be toxic.
Collapse
Affiliation(s)
| | - Namrata D Erande
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA 02142, USA
| | - Pawan Kumar
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA 02142, USA
| | - Rohan Degaonkar
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA 02142, USA
| | - Jason A Gilbert
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA 02142, USA
| | - June Qin
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA 02142, USA
| | - Martha Mendez
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA 02142, USA
| | - Lauren Blair Woods
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA 02142, USA
| | - Yongfeng Jiang
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA 02142, USA
| | - Maja M Janas
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA 02142, USA
| | - Derek K O’Flaherty
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA 02142, USA
| | - Ivan Zlatev
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA 02142, USA
| | - Mark K Schlegel
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA 02142, USA
| | - Shigeo Matsuda
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA 02142, USA
| | - Martin Egli
- Department of Biochemistry, School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
| | - Muthiah Manoharan
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA 02142, USA
| |
Collapse
|
19
|
Nikam RR, Harikrishna S, Gore KR. Synthesis, Structural, and Conformational Analysis of 4′‐
C
‐Alkyl‐2′‐
O
‐Ethyl‐Uridine Modified Nucleosides. European J Org Chem 2021. [DOI: 10.1002/ejoc.202001348] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Rahul R. Nikam
- Department of Chemistry University of Mumbai Mumbai 400098 India
| | - S. Harikrishna
- Center for Structural Biology Vanderbilt University Nashville, Tennessee 37232 United States
| | - Kiran R. Gore
- Department of Chemistry University of Mumbai Mumbai 400098 India
- Department of Chemistry Indian Institute of Technology Kharagpur Kharagpur, West Bengal 721302 India
| |
Collapse
|
20
|
4′-C-Aminoethoxy modification enhanced nuclease resistance of RNAs and improved thermal stability of RNA duplexes. RESULTS IN CHEMISTRY 2021. [DOI: 10.1016/j.rechem.2021.100231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
|
21
|
Abou Assi H, Rangadurai AK, Shi H, Liu B, Clay MC, Erharter K, Kreutz C, Holley CL, Al-Hashimi H. 2'-O-Methylation can increase the abundance and lifetime of alternative RNA conformational states. Nucleic Acids Res 2020; 48:12365-12379. [PMID: 33104789 PMCID: PMC7708057 DOI: 10.1093/nar/gkaa928] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/10/2020] [Accepted: 10/09/2020] [Indexed: 12/18/2022] Open
Abstract
2'-O-Methyl (Nm) is a highly abundant post-transcriptional RNA modification that plays important biological roles through mechanisms that are not entirely understood. There is evidence that Nm can alter the biological activities of RNAs by biasing the ribose sugar pucker equilibrium toward the C3'-endo conformation formed in canonical duplexes. However, little is known about how Nm might more broadly alter the dynamic ensembles of flexible RNAs containing bulges and internal loops. Here, using NMR and the HIV-1 transactivation response (TAR) element as a model system, we show that Nm preferentially stabilizes alternative secondary structures in which the Nm-modified nucleotides are paired, increasing both the abundance and lifetime of low-populated short-lived excited states by up to 10-fold. The extent of stabilization increased with number of Nm modifications and was also dependent on Mg2+. Through phi-value analysis, the Nm modification also provided rare insights into the structure of the transition state for conformational exchange. Our results suggest that Nm could alter the biological activities of Nm-modified RNAs by modulating their secondary structural ensembles as well as establish the utility of Nm as a tool for the discovery and characterization of RNA excited state conformations.
Collapse
Affiliation(s)
- Hala Abou Assi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Atul K Rangadurai
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Honglue Shi
- Department of Chemistry, Duke University, Durham, NC 27708, USA
| | - Bei Liu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Mary C Clay
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kevin Erharter
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - Christopher L Holley
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Hashim M Al-Hashimi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Chemistry, Duke University, Durham, NC 27708, USA
| |
Collapse
|
22
|
Gu Q, Kong L, Yang L, Zhu L, Hong R. A stereotetrad-centered approach toward pironetin: Dead ends, Detour, and evolution of the synthetic strategy. Tetrahedron 2020. [DOI: 10.1016/j.tet.2020.131660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
23
|
Mikami A, Erande N, Matsuda S, Kel'in A, Woods LB, Chickering T, Pallan PS, Schlegel MK, Zlatev I, Egli M, Manoharan M. Synthesis, chirality-dependent conformational and biological properties of siRNAs containing 5'-(R)- and 5'-(S)-C-methyl-guanosine. Nucleic Acids Res 2020; 48:10101-10124. [PMID: 32990754 PMCID: PMC7544225 DOI: 10.1093/nar/gkaa750] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 08/10/2020] [Accepted: 08/27/2020] [Indexed: 12/22/2022] Open
Abstract
Various chemical modifications have been identified that enhance potency of small interfering RNAs (siRNAs) and that reduce off-target effects, immune stimulation, and toxicities of metabolites of these therapeutic agents. We previously described 5′-C-methyl pyrimidine nucleotides also modified at the 2′ position of the sugar. Here, we describe the synthesis of 2′-position unmodified 5′-(R)- and 5′-(S)-C-methyl guanosine and evaluation of these nucleotides in the context of siRNA. The (R) isomer provided protection from 5′ exonuclease and the (S) isomer provided protection from 3′ exonuclease in the context of a terminally modified oligonucleotide. siRNA potency was maintained when these modifications were incorporated at the tested positions of sense and antisense strands. Moreover, the corresponding 5′ triphosphates were not substrates for mitochondrial DNA polymerase. Models generated based on crystal structures of 5′ and 3′ exonuclease oligonucleotide complexes with 5′-(R)- and 5′-(S)-C-methyl substituents attached to the 5′- and 3′-terminal nucleotides, respectively, provided insight into the origins of the observed protections. Structural properties of 5′-(R)-C-methyl guanosine incorporated into an RNA octamer were analysed by X-ray crystallography, and the structure explains the loss in duplex thermal stability for the (R) isomer compared with the (S) isomer. Finally, the effect of 5′-C-methylation on endoribonuclease activity has been explained.
Collapse
Affiliation(s)
- Atsushi Mikami
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, Massachusetts 02142, USA
| | - Namrata Erande
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, Massachusetts 02142, USA
| | - Shigeo Matsuda
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, Massachusetts 02142, USA
| | - Alexander Kel'in
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, Massachusetts 02142, USA
| | - Lauren Blair Woods
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, Massachusetts 02142, USA
| | - Tyler Chickering
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, Massachusetts 02142, USA
| | - Pradeep S Pallan
- Department of Biochemistry Vanderbilt University, School of Medicine Nashville, TN 37232, USA
| | - Mark K Schlegel
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, Massachusetts 02142, USA
| | - Ivan Zlatev
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, Massachusetts 02142, USA
| | - Martin Egli
- Department of Biochemistry Vanderbilt University, School of Medicine Nashville, TN 37232, USA
| | - Muthiah Manoharan
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, Massachusetts 02142, USA
| |
Collapse
|
24
|
|
25
|
Capilato JN, Pitts CR, Rowshanpour R, Dudding T, Lectka T. Site-Selective Photochemical Fluorination of Ketals: Unanticipated Outcomes in Selectivity and Stability. J Org Chem 2020; 85:2855-2864. [PMID: 32031800 DOI: 10.1021/acs.joc.9b03047] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a method for the regioselective photochemical sp3 C-H fluorination of acetonide ketals that presents interesting problems in chemical reactivity. The question of why certain products of the reaction are stable while others are not is addressed, as is the question of why only select α-ethereal hydrogen atoms are targeted in the reaction. We demonstrate that the method can be employed to synthesize unprecedented fluorinated sugars and steroids, and it can also be applied toward the fluorination of carbamates. Though some substrates contain up to eight discrete α-ethereal C-H bonds, we observed site-selectivity in each case, prompting us to investigate potential transition states for the reaction. Finally, a remarkable regiochemical switch upon minor structural modification of a diketal is also analyzed.
Collapse
Affiliation(s)
- Joseph N Capilato
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Cody Ross Pitts
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Rozhin Rowshanpour
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - Travis Dudding
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - Thomas Lectka
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| |
Collapse
|
26
|
Miroshnichenko SK, Amirloo B, Bichenkova EV, Vlassov VV, Zenkova MA, Patutina OA. 2'OMe Modification of Anti-miRNA-21 Oligonucleotide–Peptide Conjugate Improves Its Hybridization Properties and Catalytic Activity. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2020. [DOI: 10.1134/s1068162019060281] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
27
|
O'Reilly D, Kartje ZJ, Ageely EA, Malek-Adamian E, Habibian M, Schofield A, Barkau CL, Rohilla KJ, DeRossett LB, Weigle AT, Damha MJ, Gagnon KT. Extensive CRISPR RNA modification reveals chemical compatibility and structure-activity relationships for Cas9 biochemical activity. Nucleic Acids Res 2019; 47:546-558. [PMID: 30517736 PMCID: PMC6344873 DOI: 10.1093/nar/gky1214] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/29/2018] [Indexed: 12/26/2022] Open
Abstract
CRISPR (clustered regularly interspaced short palindromic repeat) endonucleases are at the forefront of biotechnology, synthetic biology and gene editing. Methods for controlling enzyme properties promise to improve existing applications and enable new technologies. CRISPR enzymes rely on RNA cofactors to guide catalysis. Therefore, chemical modification of the guide RNA can be used to characterize structure-activity relationships within CRISPR ribonucleoprotein (RNP) enzymes and identify compatible chemistries for controlling activity. Here, we introduce chemical modifications to the sugar–phosphate backbone of Streptococcus pyogenes Cas9 CRISPR RNA (crRNA) to probe chemical and structural requirements. Ribose sugars that promoted or accommodated A-form helical architecture in and around the crRNA ‘seed’ region were tolerated best. A wider range of modifications were acceptable outside of the seed, especially D-2′-deoxyribose, and we exploited this property to facilitate exploration of greater chemical diversity within the seed. 2′-fluoro was the most compatible modification whereas bulkier O-methyl sugar modifications were less tolerated. Activity trends could be rationalized for selected crRNAs using RNP stability and DNA target binding experiments. Cas9 activity in vitro tolerated most chemical modifications at predicted 2′-hydroxyl contact positions, whereas editing activity in cells was much less tolerant. The biochemical principles of chemical modification identified here will guide CRISPR-Cas9 engineering and enable new or improved applications.
Collapse
Affiliation(s)
- Daniel O'Reilly
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Zachary J Kartje
- Department of Chemistry & Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, USA
| | - Eman A Ageely
- Department of Chemistry & Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, USA
| | - Elise Malek-Adamian
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Maryam Habibian
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Annabelle Schofield
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Christopher L Barkau
- Department of Biochemistry & Molecular Biology, School of Medicine, Southern Illinois University, Carbondale, Illinois 62901, USA
| | - Kushal J Rohilla
- Department of Biochemistry & Molecular Biology, School of Medicine, Southern Illinois University, Carbondale, Illinois 62901, USA
| | - Lauren B DeRossett
- Department of Chemistry & Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, USA
| | - Austin T Weigle
- Department of Chemistry & Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, USA
| | - Masad J Damha
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Keith T Gagnon
- Department of Chemistry & Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, USA.,Department of Biochemistry & Molecular Biology, School of Medicine, Southern Illinois University, Carbondale, Illinois 62901, USA
| |
Collapse
|
28
|
Harp JM, Guenther DC, Bisbe A, Perkins L, Matsuda S, Bommineni GR, Zlatev I, Foster DJ, Taneja N, Charisse K, Maier MA, Rajeev KG, Manoharan M, Egli M. Structural basis for the synergy of 4'- and 2'-modifications on siRNA nuclease resistance, thermal stability and RNAi activity. Nucleic Acids Res 2019; 46:8090-8104. [PMID: 30107495 PMCID: PMC6144868 DOI: 10.1093/nar/gky703] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/23/2018] [Indexed: 12/11/2022] Open
Abstract
Chemical modification is a prerequisite of oligonucleotide therapeutics for improved metabolic stability, uptake and activity, irrespective of their mode of action, i.e. antisense, RNAi or aptamer. Phosphate moiety and ribose C2′/O2′ atoms are the most common sites for modification. Compared to 2′-O-substituents, ribose 4′-C-substituents lie in proximity of both the 3′- and 5′-adjacent phosphates. To investigate potentially beneficial effects on nuclease resistance we combined 2′-F and 2′-OMe with 4′-Cα- and 4′-Cβ-OMe, and 2′-F with 4′-Cα-methyl modification. The α- and β-epimers of 4′-C-OMe-uridine and the α-epimer of 4′-C-Me-uridine monomers were synthesized and incorporated into siRNAs. The 4′α-epimers affect thermal stability only minimally and show increased nuclease stability irrespective of the 2′-substituent (H, F, OMe). The 4′β-epimers are strongly destabilizing, but afford complete resistance against an exonuclease with the phosphate or phosphorothioate backbones. Crystal structures of RNA octamers containing 2′-F,4′-Cα-OMe-U, 2′-F,4′-Cβ-OMe-U, 2′-OMe,4′-Cα-OMe-U, 2′-OMe,4′-Cβ-OMe-U or 2′-F,4′-Cα-Me-U help rationalize these observations and point to steric and electrostatic origins of the unprecedented nuclease resistance seen with the chain-inverted 4′β-U epimer. We used structural models of human Argonaute 2 in complex with guide siRNA featuring 2′-F,4′-Cα-OMe-U or 2′-F,4′-Cβ-OMe-U at various sites in the seed region to interpret in vitro activities of siRNAs with the corresponding 2′-/4′-C-modifications.
Collapse
Affiliation(s)
- Joel M Harp
- Department of Biochemistry, Vanderbilt University, School of Medicine, Nashville, TN 37232, USA
| | - Dale C Guenther
- Alnylam Pharmaceuticals, 300 Third Street, Cambridge, MA 02142, USA
| | - Anna Bisbe
- Alnylam Pharmaceuticals, 300 Third Street, Cambridge, MA 02142, USA
| | - Lydia Perkins
- Alnylam Pharmaceuticals, 300 Third Street, Cambridge, MA 02142, USA
| | - Shigeo Matsuda
- Alnylam Pharmaceuticals, 300 Third Street, Cambridge, MA 02142, USA
| | | | - Ivan Zlatev
- Alnylam Pharmaceuticals, 300 Third Street, Cambridge, MA 02142, USA
| | - Donald J Foster
- Alnylam Pharmaceuticals, 300 Third Street, Cambridge, MA 02142, USA
| | - Nate Taneja
- Alnylam Pharmaceuticals, 300 Third Street, Cambridge, MA 02142, USA
| | - Klaus Charisse
- Alnylam Pharmaceuticals, 300 Third Street, Cambridge, MA 02142, USA
| | - Martin A Maier
- Alnylam Pharmaceuticals, 300 Third Street, Cambridge, MA 02142, USA
| | | | - Muthiah Manoharan
- Alnylam Pharmaceuticals, 300 Third Street, Cambridge, MA 02142, USA
- To whom correspondence should be addressed. Tel: +1 615 343 8070; Fax: +1 615 343 0704; . Correspondence may also be addressed to Muthiah Manoharan. Tel: +1 617 551 8319; Fax: +1 617 551 8101;
| | - Martin Egli
- Department of Biochemistry, Vanderbilt University, School of Medicine, Nashville, TN 37232, USA
- To whom correspondence should be addressed. Tel: +1 615 343 8070; Fax: +1 615 343 0704; . Correspondence may also be addressed to Muthiah Manoharan. Tel: +1 617 551 8319; Fax: +1 617 551 8101;
| |
Collapse
|
29
|
Malek-Adamian E, Fakhoury J, Arnold AE, Martínez-Montero S, Shoichet MS, Damha MJ. Effect of Sugar 2',4'-Modifications on Gene Silencing Activity of siRNA Duplexes. Nucleic Acid Ther 2019; 29:187-194. [PMID: 31084536 PMCID: PMC6686699 DOI: 10.1089/nat.2019.0792] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In this study, we explore the effect of a library of 2′-, 4′-, and 2′,4′-modified uridine nucleosides and their impact on silencing firefly luciferase and on down-regulated in renal cell carcinoma (DRR) gene targets. The modifications studied were 2′-F-ribose, 2′-F-arabinose, 2′-OMe-ribose, 2′-F,4′-OMe-ribose, 2′-F,4′-OMe-arabinose, and 2′-OMe,4′-F-ribose. We found that 2′,4′-modifications are well tolerated within A-form RNA duplexes, leading to virtually no change in melting temperature as assessed by UV thermal melting. The impact of the dual (2′,4′) modification was assessed by comparing gene silencing ability to 2′- or 4′- (singly) modified siRNA counterparts. siRNAs with (2′,4′)-modified overhangs generally outperformed the native siRNA as well as siRNAs with a 2′- or 4′-modified overhang, suggesting that 2′,4′-modified nucleotides interact favorably with Argonaute protein's PAZ domain. Among the most active siRNAs were those with 2′-F,4′-OMe-ribose or 2′-F,4′-OMe-arabinose at the overhangs. When modifications were placed at both overhangs and internal positions, a duplex with the 2′-F (internal) and 2′-F,4′-OMe (overhang) combination was found to be the most potent, followed by the duplex with 2′-OMe (internal) and 2′,4′-diOMe (overhang) modifications. Given the nuclease resistance exhibited by 2′,4′-modified siRNAs, particularly when the modification is placed at or near the overhangs, these findings may allow the creation of superior siRNAs for therapy.
Collapse
Affiliation(s)
| | - Johans Fakhoury
- 1Department of Chemistry, McGill University, Montreal, Canada
| | - Amy E Arnold
- 2Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | | | - Molly S Shoichet
- 2Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada.,3Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada.,4Department of Chemistry, University of Toronto, Toronto, Canada
| | - Masad J Damha
- 1Department of Chemistry, McGill University, Montreal, Canada
| |
Collapse
|
30
|
Mangla P, Maity J, Rungta P, Verma V, Sanghvi YS, Prasad AK. Synthesis of 6′‐Methyl‐2′‐
O
,4′‐
C
‐methylene‐
α
‐L‐ ribofuranosyl‐pyrimidine Nucleosides. ChemistrySelect 2019. [DOI: 10.1002/slct.201900809] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Priyanka Mangla
- Bioorganic Laboratory, Department of ChemistryUniversity of Delhi Delhi- 110 007 India
| | - Jyotirmoy Maity
- Bioorganic Laboratory, Department of ChemistryUniversity of Delhi Delhi- 110 007 India
| | - Pallavi Rungta
- Bioorganic Laboratory, Department of ChemistryUniversity of Delhi Delhi- 110 007 India
| | - Vineet Verma
- Bioorganic Laboratory, Department of ChemistryUniversity of Delhi Delhi- 110 007 India
| | | | - Ashok K. Prasad
- Bioorganic Laboratory, Department of ChemistryUniversity of Delhi Delhi- 110 007 India
| |
Collapse
|
31
|
Akabane-Nakata M, Kumar P, Das RS, Erande ND, Matsuda S, Egli M, Manoharan M. Synthesis and Biophysical Characterization of RNAs Containing 2'-Fluorinated Northern Methanocarbacyclic Nucleotides. Org Lett 2019; 21:1963-1967. [PMID: 30892051 DOI: 10.1021/acs.orglett.8b04153] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
2'-Fluorinated Northern methanocarbacyclic (2'-F-NMC) nucleosides and phosphoramidites, based on a bicyclo[3.1.0]hexane scaffold bearing all four natural nucleobases (U, C, A, and G), were synthesized to enable exploration of this novel nucleotide modification related to the clinically validated 2'-deoxy-2'-fluororibonucleotides (2'-F-RNA). Biophysical properties of the 2'-F-NMC-containing oligonucleotides were evaluated. A duplex of 2'-F-NMC-modified oligonucleotide with RNA exhibited thermal stability similar to that of the parent RNA duplex, 2'-F-NMC-modified oligonucleotides had higher stability against 5'- and 3'-exonucleolytic degradation than the corresponding oligonucleotides modified with 2'-F-RNA, and 2'-F-NMC-modified oligonucleotides exhibited higher lipophilicity than the corresponding RNA oligonucleotides as well as those modified with 2'-F-RNA.
Collapse
Affiliation(s)
- Masaaki Akabane-Nakata
- Alnylam Pharmaceuticals , 300 Third Street , Cambridge , Massachusetts 02142 , United States
| | - Pawan Kumar
- Alnylam Pharmaceuticals , 300 Third Street , Cambridge , Massachusetts 02142 , United States
| | - Rajat S Das
- Alnylam Pharmaceuticals , 300 Third Street , Cambridge , Massachusetts 02142 , United States
| | - Namrata D Erande
- Alnylam Pharmaceuticals , 300 Third Street , Cambridge , Massachusetts 02142 , United States
| | - Shigeo Matsuda
- Alnylam Pharmaceuticals , 300 Third Street , Cambridge , Massachusetts 02142 , United States
| | - Martin Egli
- Department of Biochemistry, School of Medicine , Vanderbilt University , Nashville , Tennessee 37232 , United States
| | - Muthiah Manoharan
- Alnylam Pharmaceuticals , 300 Third Street , Cambridge , Massachusetts 02142 , United States
| |
Collapse
|
32
|
O'Reilly D, Stein RS, Patrascu MB, Jana SK, Kurian J, Moitessier N, Damha MJ. Exploring Atypical Fluorine-Hydrogen Bonds and Their Effects on Nucleoside Conformations. Chemistry 2018; 24:16432-16439. [PMID: 30125398 DOI: 10.1002/chem.201803940] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Indexed: 12/16/2022]
Affiliation(s)
- Daniel O'Reilly
- Department of Chemistry; McGill University; Otto Maass Chemistry Bldg.; 801 Sherbrooke St. West Montreal QC, H3C0B8 Canada
| | - Robin S. Stein
- Department of Chemistry; McGill University; Otto Maass Chemistry Bldg.; 801 Sherbrooke St. West Montreal QC, H3C0B8 Canada
| | - Mihai Burai Patrascu
- Department of Chemistry; McGill University; Otto Maass Chemistry Bldg.; 801 Sherbrooke St. West Montreal QC, H3C0B8 Canada
| | - Sunit Kumar Jana
- Department of Chemistry; McGill University; Otto Maass Chemistry Bldg.; 801 Sherbrooke St. West Montreal QC, H3C0B8 Canada
| | - Jerry Kurian
- Department of Chemistry; McGill University; Otto Maass Chemistry Bldg.; 801 Sherbrooke St. West Montreal QC, H3C0B8 Canada
| | - Nicolas Moitessier
- Department of Chemistry; McGill University; Otto Maass Chemistry Bldg.; 801 Sherbrooke St. West Montreal QC, H3C0B8 Canada
| | - Masad J. Damha
- Department of Chemistry; McGill University; Otto Maass Chemistry Bldg.; 801 Sherbrooke St. West Montreal QC, H3C0B8 Canada
| |
Collapse
|