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Kaur J, Sharma A, Mundlia P, Sood V, Pandey A, Singh G, Barnwal RP. RNA-Small-Molecule Interaction: Challenging the "Undruggable" Tag. J Med Chem 2024. [PMID: 38498010 DOI: 10.1021/acs.jmedchem.3c01354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
RNA targeting, specifically with small molecules, is a relatively new and rapidly emerging avenue with the promise to expand the target space in the drug discovery field. From being "disregarded" as an "undruggable" messenger molecule to FDA approval of an RNA-targeting small-molecule drug Risdiplam, a radical change in perspective toward RNA has been observed in the past decade. RNAs serve important regulatory functions beyond canonical protein synthesis, and their dysregulation has been reported in many diseases. A deeper understanding of RNA biology reveals that RNA molecules can adopt a variety of structures, carrying defined binding pockets that can accommodate small-molecule drugs. Due to its functional diversity and structural complexity, RNA can be perceived as a prospective target for therapeutic intervention. This perspective highlights the proof of concept of RNA-small-molecule interactions, exemplified by targeting of various transcripts with functional modulators. The advent of RNA-oriented knowledge would help expedite drug discovery.
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Affiliation(s)
- Jaskirat Kaur
- Department of Biophysics, Panjab University, Chandigarh 160014, India
| | - Akanksha Sharma
- Department of Biophysics, Panjab University, Chandigarh 160014, India
- University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh 160014, India
| | - Poonam Mundlia
- Department of Biophysics, Panjab University, Chandigarh 160014, India
| | - Vikas Sood
- Department of Biochemistry, Jamia Hamdard, New Delhi 110062, India
| | - Ankur Pandey
- Department of Chemistry, Panjab University, Chandigarh 160014, India
| | - Gurpal Singh
- University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh 160014, India
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Fedorova O, Arhin G, Pyle AM, Frank AT. In Silico Discovery of Group II Intron RNA Splicing Inhibitors. ACS Chem Biol 2023; 18:1968-1975. [PMID: 37602469 DOI: 10.1021/acschembio.3c00160] [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: 08/22/2023]
Abstract
Here, we describe the discovery of compounds that inhibit self-splicing in group II introns. Using docking calculations, we targeted the catalytic active site within the Oceanobacillus iheyensis group IIC intron and virtually screened a library of lead-like compounds. From this initial virtual screen, we identified three unique scaffolds that inhibit splicing in vitro. Additional tests revealed that an analog of the lead scaffold inhibits splicing in an intron-dependent manner. Furthermore, this analog exhibited activity against the group II intron from a different class: the yeast ai5γ IIB intron. The splicing inhibitors we identified could serve as chemical tools for developing group II intron-targeted antifungals, and, more broadly, our results highlight the potential of in silico techniques for identifying bioactive hits against structured and functionally complex RNAs.
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Affiliation(s)
| | - Grace Arhin
- Biophysics Program, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Anna Marie Pyle
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Aaron T Frank
- Biophysics Program, University of Michigan, Ann Arbor, Michigan 48109, United States
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3
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Wu Y, Brooks CL. Flexible CDOCKER: Hybrid Searching Algorithm and Scoring Function with Side Chain Conformational Entropy. J Chem Inf Model 2021; 61:5535-5549. [PMID: 34704754 PMCID: PMC8684595 DOI: 10.1021/acs.jcim.1c01078] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The binding of small-molecule ligands to protein or nucleic acid targets is important to numerous biological processes. Accurate prediction of the binding modes between a ligand and a macromolecule is of fundamental importance in structure-based structure-function exploration. When multiple ligands with different sizes are docked to a target receptor, it is reasonable to assume that the residues in the binding pocket may adopt alternative conformations upon interacting with the different ligands. In addition, it has been suggested that the entropic contribution to binding can be important. However, only a few attempts to include the side chain conformational entropy upon binding within the application of flexible receptor docking methodology exist. Here, we propose a new physics-based scoring function that includes both enthalpic and entropic contributions upon binding by considering the conformational variability of the flexible side chains within the ensemble of docked poses. We also describe a novel hybrid searching algorithm that combines both molecular dynamics (MD)-based simulated annealing and genetic algorithm crossovers to address the enhanced sampling of the increased search space. We demonstrate improved accuracy in flexible cross-docking experiments compared with rigid cross-docking. We test our developments by considering five protein targets, thrombin, dihydrofolate reductase(DHFR), T4 L99A, T4 L99A/M102Q, and PDE10A, which belong to different enzyme classes with different binding pocket environments, as a representative set of diverse ligands and receptors. Each target contains dozens of different ligands bound to the same binding pocket. We also demonstrate that this flexible docking algorithm may be applicable to RNA docking with a representative riboswitch example. Our findings show significant improvements in top ranking accuracy across this set, with the largest improvement relative to rigid, 23.64%, occurring for ligands binding to DHFR. We then evaluate the ability to identify lead compounds among a large chemical space for the proposed flexible receptor docking algorithm using a subset of the DUD-E containing receptor targets MCR, GCR, and ANDR. We demonstrate that our new algorithms show improved performance in modeling flexible binding site residues compared to DOCK. Finally, we select the T4 L99A and T4 L99A/M102Q decoy sets, containing dozens of binders and experimentally validated nonbinders, to test our approach in distinguishing binders from nonbinders. We illustrate that our new algorithms for searching and scoring have superior performance to rigid receptor CDOCKER as well as AutoDock Vina. Finally, we suggest that flexible CDOCKER is sufficiently fast to be utilized in high-throughput docking screens in the context of hierarchical approaches.
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Affiliation(s)
- Yujin Wu
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Charles L Brooks
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Biophysics Program, University of Michigan, Ann Arbor, Michigan 48109, United States
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Manigrasso J, Marcia M, De Vivo M. Computer-aided design of RNA-targeted small molecules: A growing need in drug discovery. Chem 2021. [DOI: 10.1016/j.chempr.2021.05.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Wu J, Wang S, Li X, Zhang Q, Yang J, Ma Y, Guan Z, Yang Z. Selective Anti-melanoma Effect of Phosphothioated Aptamer Encapsulated by Neutral Cytidinyl/Cationic Lipids. Front Cell Dev Biol 2021; 9:660233. [PMID: 34262898 PMCID: PMC8273494 DOI: 10.3389/fcell.2021.660233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 06/01/2021] [Indexed: 12/11/2022] Open
Abstract
BC15-31 is a DNA aptamer that targets heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1), which plays a crucial role in the process of pre-RNA maturation and is also essential for the rapid proliferation of tumor cells. In this research, we modified BC15-31 with a phosphorothioate (PS) backbone, LNA, and 2-O-MOE to enhance its stability and target affinity. In addition, a neutral cytidinyl lipid (DNCA) and a cationic lipid (CLD) were mixed to encapsulate modified aptamers with the aim of improving their cell permeability with low toxicity. Under the DNCA/CLD package, aptamers are mainly distributed in the nucleus. A modified sequence WW-24 showed an excellent selective anti-melanoma (A375 cells, ∼25 nM, 80%) activity, targeted to both hnRNP A1 and hnRNP A2/B1 found by the BLI experiment, and induced more early and late apoptosis in vitro, which also showed stronger antitumor effect and longer accumulation time in vivo. These results provide a new strategy for further clinical applications.
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Affiliation(s)
- Jing Wu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Shuhe Wang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Xiang Li
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Qi Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Jie Yang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Yuan Ma
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Zhu Guan
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Zhenjun Yang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
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Al-Masoudi NA, Essa AH, Alwaaly AA, Saeed BA, Langer P. Synthesis and conformational analysis of new arylated-diphenylurea derivatives related to sorafenib drug via Suzuki-Miyaura cross-coupling reaction. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.06.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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7
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In silico identification of novel ligands for G-quadruplex in the c-MYC promoter. J Comput Aided Mol Des 2014; 29:339-48. [PMID: 25527072 DOI: 10.1007/s10822-014-9826-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 12/11/2014] [Indexed: 10/24/2022]
Abstract
G-quadruplex DNA formed in NHEIII1 region of oncogene promoter inhibits transcription of the genes. In this study, virtual screening combining pharmacophore-based search and structure-based docking screening was conducted to discover ligands binding to G-quadruplex in promoter region of c-MYC. Several hit ligands showed the selective PCR-arresting effects for oligonucleotide containing c-MYC G-quadruplex forming sequence. Among them, three hits selectively inhibited cell proliferation and decreased c-MYC mRNA level in Ramos cells, where NHEIII1 is included in translocated c-MYC gene for overexpression. Promoter assay using two kinds of constructs with wild-type and mutant sequences showed that interaction of these ligands with the G-quadruplex resulted in turning-off of the reporter gene. In conclusion, combined virtual screening methods were successfully used for discovery of selective c-MYC promoter G-quadruplex binders with anticancer activity.
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Daldrop P, Brenk R. Structure-based virtual screening for the identification of RNA-binding ligands. Methods Mol Biol 2014; 1103:127-39. [PMID: 24318891 DOI: 10.1007/978-1-62703-730-3_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Structure-based virtual screening exploits the 3D structure of the target as a template for the discovery of new ligands. It is a key method for hit discovery and was originally developed for protein targets. Recently, this method has also been applied to RNA targets. This chapter gives an overview of this method and its application in the context of ligand discovery for RNA. In addition, it describes in detail how to conduct virtual screening for RNA targets, making use of software that is free for noncommercial use. Some advice on how to avoid common pitfalls in virtual screening is also given.
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Affiliation(s)
- Peter Daldrop
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, UK
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Dinman JD. Virtual Screening for RNA-Interacting Small Molecules. BIOPHYSICAL APPROACHES TO TRANSLATIONAL CONTROL OF GENE EXPRESSION 2012. [PMCID: PMC7123052 DOI: 10.1007/978-1-4614-3991-2_12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Computational virtual screening is useful and powerful strategy for rapid discovery of small biologically active molecules in the early stage of drug discovery. The discovery of a broad range of important biological processes involved by RNA has increased the importance of RNA as a new drug target. To apply structure-based virtual screening methods to the discovery of RNA-binding ligands, many RNA 3D structure prediction programs and optimized docking algorithms have been developed. In this chapter, a number of successful cases of virtual screening targeting RNA will be introduced.
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Affiliation(s)
- Jonathan D. Dinman
- College Park, Cell Biology and Molecular Genetics, University of Maryland, Rm. 2135 Microbiology Building, College Park, 20742-4451 Maryland USA
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Türkel S, Kaplan G, Farabaugh PJ. Glucose signalling pathway controls the programmed ribosomal frameshift efficiency in retroviral-like element Ty3 in Saccharomyces cerevisiae. Yeast 2011; 28:799-808. [PMID: 21989811 PMCID: PMC7169698 DOI: 10.1002/yea.1906] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 08/13/2011] [Accepted: 08/30/2011] [Indexed: 12/22/2022] Open
Abstract
Ty3 elements of S. cerevisiae contain two overlapping coding regions, GAG3 and POL3, which are functional homologues of retroviral gag and pol genes, respectively. Pol3 is translated as a Gag3‐Pol3 fusion protein dependent on a +1 programmed frameshift at a site with the overlap between the two genes. We show that the Ty3 frameshift frequency varies up to 10‐fold in S. cerevisiae cells depending on carbon source. Frameshift efficiency is significantly lower in cells growing on glucose as carbon source than in cells growing on poor alternative carbon sources (glycerol/lactate or galactose). Our results indicate that Ty3 programmed ribosomal frameshift efficiency in response to glucose signalling requires two protein kinases: Snf1p and cAMP‐dependent protein kinase A (PKA). Increased frameshifting on alternative carbon sources also appears to require cytoplasmic localization of Snf1p, mediated by the Sip2p protein. In addition to the two required protein kinases, our results implicate that Stm1p, a ribosome‐associated protein involved in nutrient sensing, is essential for the carbon source‐dependent regulation of Ty3 frameshifting. These data indicate that Ty3 programmed ribosomal frameshift is not a constitutive process but that it is regulated in response to the glucose‐signalling pathway. Copyright © 2011 John Wiley & Sons, Ltd.
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Affiliation(s)
- Sezai Türkel
- Uludag University, Faculty of Arts and Sciences, Department of Biology, 16059-, Bursa, Turkey.
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Annexin A2 binds RNA and reduces the frameshifting efficiency of infectious bronchitis virus. PLoS One 2011; 6:e24067. [PMID: 21918681 PMCID: PMC3168876 DOI: 10.1371/journal.pone.0024067] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 07/29/2011] [Indexed: 12/15/2022] Open
Abstract
Annexin A2 (ANXA2) is a protein implicated in diverse cellular functions, including exocytosis, DNA synthesis and cell proliferation. It was recently proposed to be involved in RNA metabolism because it was shown to associate with some cellular mRNA. Here, we identified ANXA2 as a RNA binding protein (RBP) that binds IBV (Infectious Bronchitis Virus) pseudoknot RNA. We first confirmed the binding of ANXA2 to IBV pseudoknot RNA by ultraviolet crosslinking and showed its binding to RNA pseudoknot with ANXA2 protein in vitro and in the cells. Since the RNA pseudoknot located in the frameshifting region of IBV was used as bait for cellular RBPs, we tested whether ANXA2 could regulate the frameshfting of IBV pseudoknot RNA by dual luciferase assay. Overexpression of ANXA2 significantly reduced the frameshifting efficiency from IBV pseudoknot RNA and knockdown of the protein strikingly increased the frameshifting efficiency. The results suggest that ANXA2 is a cellular RBP that can modulate the frameshifting efficiency of viral RNA, enabling it to act as an anti-viral cellular protein, and hinting at roles in RNA metabolism for other cellular mRNAs.
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Daldrop P, Reyes FE, Robinson DA, Hammond CM, Lilley DM, Batey RT, Brenk R. Novel ligands for a purine riboswitch discovered by RNA-ligand docking. ACTA ACUST UNITED AC 2011; 18:324-35. [PMID: 21439477 PMCID: PMC3119931 DOI: 10.1016/j.chembiol.2010.12.020] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 12/02/2010] [Accepted: 12/29/2010] [Indexed: 01/01/2023]
Abstract
The increasing number of RNA crystal structures enables a structure-based approach to the discovery of new RNA-binding ligands. To develop the poorly explored area of RNA-ligand docking, we have conducted a virtual screening exercise for a purine riboswitch to probe the strengths and weaknesses of RNA-ligand docking. Using a standard protein-ligand docking program with only minor modifications, four new ligands with binding affinities in the micromolar range were identified, including two compounds based on molecular scaffolds not resembling known ligands. RNA-ligand docking performed comparably to protein-ligand docking indicating that this approach is a promising option to explore the wealth of RNA structures for structure-based ligand design.
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Affiliation(s)
- Peter Daldrop
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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Park SJ, Kim YG, Park HJ. Identification of RNA pseudoknot-binding ligand that inhibits the -1 ribosomal frameshifting of SARS-coronavirus by structure-based virtual screening. J Am Chem Soc 2011; 133:10094-100. [PMID: 21591761 DOI: 10.1021/ja1098325] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Programmed -1 ribosomal frameshifting (-1 RF) is an essential regulating mechanism of translation used by SARS-CoV (severe acute respiratory syndrome coronavirus) to synthesize the key replicative proteins encoded by two overlapping open reading frames. The integrity of RNA pseudoknot stability and structure in the -1 RF site is important for efficient -1 RF. Thus, small molecules interacting with high affinity and selectivity with the RNA pseudoknot in the -1 RF site of SARS-CoV (SARS-pseudoknot) would disrupt -1 RF and be fatal to viral infectivity and production. To discover ligands for the SARS-pseudoknot by virtual screening, we constructed a 3D structural model of the SARS-pseudoknot and conducted a computational screening of the chemical database. After virtual screening of about 80,000 compounds against the SARS-pseudoknot structure, high-ranked compounds were selected and their activities were examined by in vitro and cell-based -1 RF assay. We successfully identified a novel ligand 43 that dramatically inhibits the -1 RF of SARS-CoV. This antiframeshift agent is an interesting lead for the design of novel antiviral agents against SARS-CoV.
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Affiliation(s)
- So-Jung Park
- School of Pharmacy, Sungkyunkwan University, Suwon 440-746, Korea
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Abstract
Bacterial ribosomal RNA is the target of clinically important antibiotics, while biologically important RNAs in viral and eukaryotic genomes present a range of potential drug targets. The physicochemical properties of RNA present difficulties for medicinal chemistry, particularly when oral availability is needed. Peptidic ligands and analysis of their RNA-binding properties are providing insight into RNA recognition. RNA-binding ligands include far more chemical classes than just aminoglycosides. Chemical functionalities from known RNA-binding small molecules are being exploited in fragment- and ligand-based projects. While targeting of RNA for drug design is very challenging, continuing advances in our understanding of the principles of RNA–ligand interaction will be necessary to realize the full potential of this class of targets.
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Abstract
Programmed ribosomal frameshifting (PRF) is one of the multiple translational recoding processes that fundamentally alters triplet decoding of the messenger RNA by the elongating ribosome. The ability of the ribosome to change translational reading frames in the −1 direction (−1 PRF) is employed by many positive strand RNA viruses, including economically important plant viruses and many human pathogens, such as retroviruses, e.g., HIV-1, and coronaviruses, e.g., the causative agent of severe acute respiratory syndrome (SARS), in order to properly express their genomes. −1 PRF is programmed by a bipartite signal embedded in the mRNA and includes a heptanucleotide “slip site” over which the paused ribosome “backs up” by one nucleotide, and a downstream stimulatory element, either an RNA pseudoknot or a very stable RNA stem–loop. These two elements are separated by six to eight nucleotides, a distance that places the 5′ edge of the downstream stimulatory element in direct contact with the mRNA entry channel of the 30S ribosomal subunit. The precise mechanism by which the downstream RNA stimulates −1 PRF by the translocating ribosome remains unclear. This review summarizes the recent structural and biophysical studies of RNA pseudoknots and places this work in the context of our evolving mechanistic understanding of translation elongation. Support for the hypothesis that the downstream stimulatory element provides a kinetic barrier to the ribosome-mediated unfolding is discussed.
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