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Murray MT, Wetmore SD. Unlocking precision in aptamer engineering: a case study of the thrombin binding aptamer illustrates why modification size, quantity, and position matter. Nucleic Acids Res 2024:gkae729. [PMID: 39217472 DOI: 10.1093/nar/gkae729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Revised: 08/02/2024] [Accepted: 08/23/2024] [Indexed: 09/04/2024] Open
Abstract
The thrombin binding aptamer (TBA) is a prototypical platform used to understand the impact of chemically-modified nucleotides on aptamer stability and target affinity. To provide structural insight into the experimentally-observed effects of modification size, location, and number on aptamer performance, long time-scale molecular dynamics (MD) simulations were performed on multiple binding orientations of TBA-thrombin complexes that contain a large, flexible tryptophan thymine derivative (T-W) or a truncated analogue (T-K). Depending on modification position, T-W alters aptamer-target binding orientations, fine-tunes aptamer-target interactions, strengthens networks of nucleic acid-protein contacts, and/or induces target conformational changes to enhance binding. The proximity and 5'-to-3' directionality of nucleic acid structural motifs also play integral roles in the behavior of the modifications. Modification size can differentially influence target binding by promoting more than one aptamer-target binding pose. Multiple modifications can synergistically strengthen aptamer-target binding by generating novel nucleic acid-protein structural motifs that are unobtainable for single modifications. By studying a diverse set of modified aptamers, our work uncovers design principles that must be considered in the future development of aptamers containing chemically-modified nucleotides for applications in medicine and biotechnology, highlighting the value of computational studies in nucleic acids research.
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Affiliation(s)
- Makay T Murray
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
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Berzal-Herranz A, Romero-López C. Aptamers' Potential to Fill Therapeutic and Diagnostic Gaps. Pharmaceuticals (Basel) 2024; 17:105. [PMID: 38256938 PMCID: PMC10818422 DOI: 10.3390/ph17010105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 12/22/2023] [Accepted: 01/04/2024] [Indexed: 01/24/2024] Open
Abstract
More than 30 years ago, in 1990, three independent research groups published several papers demonstrating that genetics could be performed in vitro in the absence of living organisms or cells [...].
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Affiliation(s)
- Alfredo Berzal-Herranz
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas. PTS Granada, Av. del Conocimiento 17, 18016 Granada, Spain
| | - Cristina Romero-López
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas. PTS Granada, Av. del Conocimiento 17, 18016 Granada, Spain
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Kohn EM, Konovalov K, Gomez CA, Hoover GN, Yik AKH, Huang X, Martell JD. Terminal Alkyne-Modified DNA Aptamers with Enhanced Protein Binding Affinities. ACS Chem Biol 2023; 18:1976-1984. [PMID: 37531184 DOI: 10.1021/acschembio.3c00183] [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] [Indexed: 08/03/2023]
Abstract
Nucleic acid-based receptors, known as aptamers, are relatively fast to discover and manufacture but lack the diverse functional groups of protein receptors (e.g., antibodies). The binding properties of DNA aptamers can be enhanced by attaching abiotic functional groups; for example, aromatic groups such as naphthalene slow dissociation from proteins. Although the terminal alkyne is a π-electron-rich functional group that has been used in small molecule drugs to enhance binding to proteins through noncovalent interactions, it remains unexplored for enhancing DNA aptamer binding affinity. Here, we demonstrate the utility of the terminal alkyne for improving the binding of DNA to proteins. We prepared a library of 256 terminal-alkyne-bearing variants of HD22, a DNA aptamer that binds the protein thrombin with nanomolar affinity. After a one-step thrombin-binding selection, a high-affinity aptamer containing two alkynes was discovered, exhibiting 3.2-fold tighter thrombin binding than the corresponding unmodified sequence. The tighter binding was attributable to a slower rate of dissociation from thrombin (5.2-fold slower than HD22). Molecular dynamics simulations with enhanced sampling by Replica Exchange with Solute Tempering (REST2) suggest that the π-electron-rich alkyne interacts with an asparagine side chain N-H group on thrombin, forming a noncovalent interaction that stabilizes the aptamer-protein interface. Overall, this work represents the first case of terminal alkynes enhancing the binding properties of an aptamer and underscores the utility of the terminal alkyne as an atom economical π-electron-rich functional group to enhance binding affinity with minimal steric perturbation.
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Affiliation(s)
- Eric M Kohn
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Kirill Konovalov
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Theoretical Chemistry Institute, Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Christian A Gomez
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Gillian N Hoover
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Andrew Kai-Hei Yik
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Theoretical Chemistry Institute, Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Xuhui Huang
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Theoretical Chemistry Institute, Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Jeffrey D Martell
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705, United States
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Shien Yeoh T, Yusof Hazrina H, Bukari BA, Tang TH, Citartan M. Generation of an RNA aptamer against LipL32 of Leptospira isolated by Tripartite-hybrid SELEX coupled with in-house Python-aided unbiased data sorting. Bioorg Med Chem 2023; 81:117186. [PMID: 36812779 DOI: 10.1016/j.bmc.2023.117186] [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: 04/27/2022] [Revised: 01/16/2023] [Accepted: 01/23/2023] [Indexed: 02/05/2023]
Abstract
Leptospirosis is a potentially life-threatening zoonosis caused by pathogenic Leptospira. The major hurdle of the diagnosis of Leptospirosis lies in the issues associated with current methods of detection, which are time-consuming, tedious and the need for sophisticated, special equipments. Restrategizing the diagnostics of Leptospirosis may involve considerations of the direct detection of the outer membrane protein, which can be faster, cost-saving and require fewer equipments. One such promising marker is LipL32, which is an antigen with high amino acid sequence conservation among all the pathogenic strains. In this study, we endeavored to isolate an aptamer against LipL32 protein via a modified SELEX strategy known as tripartite-hybrid SELEX, based on 3 different partitioning strategies. In this study, we also demonstrated the deconvolution of the candidate aptamers by using in-house Python-aided unbiased data sorting in examining multiple parameters to isolate potent aptamers. We have successfully generated an RNA aptamer against LipL32 of Leptospira, LepRapt-11, which is applicable in a simple direct ELASA for the detection of LipL32. LepRapt-11 can be a promising molecular recognition element for the diagnosis of leptospirosis by targeting LipL32.
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Affiliation(s)
- Tzi Shien Yeoh
- Department of Biomedical Science, Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia, Bertam, 13200 Kepala Batas, Penang, Malaysia
| | - Hamdani Yusof Hazrina
- Department of Biomedical Science, Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia, Bertam, 13200 Kepala Batas, Penang, Malaysia
| | - Bakhtiar A Bukari
- School of Medicine, Deakin University, 3216 Geelong, Victoria, Australia
| | - Thean-Hock Tang
- Department of Biomedical Science, Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia, Bertam, 13200 Kepala Batas, Penang, Malaysia
| | - Marimuthu Citartan
- Department of Biomedical Science, Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia, Bertam, 13200 Kepala Batas, Penang, Malaysia.
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Roxo C, Pasternak A. Changes in physicochemical and anticancer properties modulated by chemically modified sugar moieties within sequence-related G-quadruplex structures. PLoS One 2022; 17:e0273528. [PMID: 35998148 PMCID: PMC9397905 DOI: 10.1371/journal.pone.0273528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 08/09/2022] [Indexed: 11/18/2022] Open
Abstract
We systematically investigated the influence of locked nucleic acid (LNA), unlock nucleic acid (UNA), and 2’-O-methyl-RNA (2’-O-Me-RNA) residues on the thermal stability, structure folding topology, biological activity and enzymatic resistance of three sequence-related DNA G-quadruplexes. In order to better understand the mechanism of action of the studied modifications, a single-position substitution in the loops or G-tetrads was performed and their influence was analyzed for a total of twenty-seven modified G-quadruplex variants. The studies show that the influence of each modification on the physicochemical properties of G-quadruplexes is position-dependent, due to mutual interactions between G-tetrads, loops, and additional guanosine at 5’ or 3’ end. Nevertheless, the anticancer activity of the modified G-quadruplexes is determined by their structure, thus also by the local changes of chemical character of sugar moieties, what might influence the specific interactions with therapeutic targets. In general, UNA modifications are efficient modulators of the G-quadruplex thermodynamic stability, however they are poor tools to improve the anticancer properties. In contrast, LNA and 2’-O-Me-RNA modified G-quadruplexes demonstrated certain antiproliferative potential and might be used as molecular tools for designing novel G-quadruplex-based therapeutics.
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Affiliation(s)
- Carolina Roxo
- Department of Nucleic Acids Bioengineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Anna Pasternak
- Department of Nucleic Acids Bioengineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
- * E-mail:
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