1
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Zhang S, Li J, Chen SJ. Machine learning in RNA structure prediction: Advances and challenges. Biophys J 2024:S0006-3495(24)00067-5. [PMID: 38297836 DOI: 10.1016/j.bpj.2024.01.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/08/2024] [Accepted: 01/24/2024] [Indexed: 02/02/2024] Open
Abstract
RNA molecules play a crucial role in various biological processes, with their functionality closely tied to their structures. The remarkable advancements in machine learning techniques for protein structure prediction have shown promise in the field of RNA structure prediction. In this perspective, we discuss the advances and challenges encountered in constructing machine learning-based models for RNA structure prediction. We explore topics including model building strategies, specific challenges involved in predicting RNA secondary (2D) and tertiary (3D) structures, and approaches to these challenges. In addition, we highlight the advantages and challenges of constructing RNA language models. Given the rapid advances of machine learning techniques, we anticipate that machine learning-based models will serve as important tools for predicting RNA structures, thereby enriching our understanding of RNA structures and their corresponding functions.
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Affiliation(s)
- Sicheng Zhang
- Department of Physics and Institute of Data Science and Informatics, University of Missouri, Columbia, Missouri
| | - Jun Li
- Department of Physics and Institute of Data Science and Informatics, University of Missouri, Columbia, Missouri
| | - Shi-Jie Chen
- Department of Physics and Institute of Data Science and Informatics, University of Missouri, Columbia, Missouri; Department of Biochemistry, University of Missouri, Columbia, Missouri.
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2
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Niu X, Xu Z, Zhang Y, Zuo X, Chen C, Fang X. Structural and dynamic mechanisms for coupled folding and tRNA recognition of a translational T-box riboswitch. Nat Commun 2023; 14:7394. [PMID: 37968328 PMCID: PMC10651847 DOI: 10.1038/s41467-023-43232-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 11/03/2023] [Indexed: 11/17/2023] Open
Abstract
T-box riboswitches are unique riboregulators where gene regulation is mediated through interactions between two highly structured RNAs. Despite extensive structural insights, how RNA-RNA interactions drive the folding and structural transitions of T-box to achieve functional conformations remains unclear. Here, by combining SAXS, single-molecule FRET and computational modeling, we elaborate the folding energy landscape of a translational T-box aptamer consisting of stems I, II and IIA/B, which Mg2+-induced global folding and tRNA binding are cooperatively coupled. smFRET measurements reveal that high Mg2+ stabilizes IIA/B and its stacking on II, which drives the pre-docking of I and II into a competent conformation, subsequent tRNA binding promotes docking of I and II to form a high-affinity tRNA binding groove, of which the essentiality of IIA/B and S-turn in II is substantiated with mutational analysis. We highlight a delicate balance among Mg2+, the intra- and intermolecular RNA-RNA interactions in modulating RNA folding and function.
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Affiliation(s)
- Xiaolin Niu
- Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Zhonghe Xu
- Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yufan Zhang
- Key Laboratory of RNA Science and Engineering, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xiaobing Zuo
- X-ray Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Chunlai Chen
- Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing, 100084, China.
| | - Xianyang Fang
- Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Key Laboratory of RNA Science and Engineering, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
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3
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Hori N, Thirumalai D. Watching ion-driven kinetics of ribozyme folding and misfolding caused by energetic and topological frustration one molecule at a time. Nucleic Acids Res 2023; 51:10737-10751. [PMID: 37758176 PMCID: PMC10602927 DOI: 10.1093/nar/gkad755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 08/23/2023] [Accepted: 09/05/2023] [Indexed: 10/03/2023] Open
Abstract
Folding of ribozymes into well-defined tertiary structures usually requires divalent cations. How Mg2+ ions direct the folding kinetics has been a long-standing unsolved problem because experiments cannot detect the positions and dynamics of ions. To address this problem, we used molecular simulations to dissect the folding kinetics of the Azoarcus ribozyme by monitoring the path each molecule takes to reach the folded state. We quantitatively establish that Mg2+ binding to specific sites, coupled with counter-ion release of monovalent cations, stimulate the formation of secondary and tertiary structures, leading to diverse pathways that include direct rapid folding and trapping in misfolded structures. In some molecules, key tertiary structural elements form when Mg2+ ions bind to specific RNA sites at the earliest stages of the folding, leading to specific collapse and rapid folding. In others, the formation of non-native base pairs, whose rearrangement is needed to reach the folded state, is the rate-limiting step. Escape from energetic traps, driven by thermal fluctuations, occurs readily. In contrast, the transition to the native state from long-lived topologically trapped native-like metastable states is extremely slow. Specific collapse and formation of energetically or topologically frustrated states occur early in the assembly process.
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Affiliation(s)
- Naoto Hori
- Department of Chemistry, University of Texas, Austin, TX 78712, USA
- School of Pharmacy, University of Nottingham, Nottingham, UK
| | - D Thirumalai
- Department of Chemistry, University of Texas, Austin, TX 78712, USA
- Department of Physics, University of Texas, Austin, TX 78712, USA
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4
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Sarkar R, Singh RK, Roy S. Hierarchical Hydration Dynamics of RNA with Nano-Water-Pool at Its Core. J Phys Chem B 2023; 127:6903-6919. [PMID: 37506269 DOI: 10.1021/acs.jpcb.3c03553] [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: 07/30/2023]
Abstract
Many functional RNAs fold into a compact, roughly globular shape by minimizing the electrostatic repulsion between their negatively charged phosphodiester backbone. The fold of such close, compact RNA architecture is often so designed that its outer surface and complex core both are predominately populated by phosphate groups loosely sequestering bases in the intermediate layers. A number of helical junctions maintain the RNA core and its nano-water-pool. While the folding of RNA is manifested by its counterion environment composed of mixed mono- and divalent salts, the concerted role of ion and water in maintaining an RNA fold is yet to be explored. In this work, detailed atomistic simulations of SAM-I and Add Adenine riboswitch aptamers, and subgenomic flavivirus RNA (sfRNA) have been performed in a physiological mixed mono- and divalent salt environment. All three RNA systems have compact folds with a core diameter of range 1-1.7 nm. The spatiotemporal heterogeneity of RNA hydration was probed in a layer-wise manner by distinguishing the core, the intermediate, and the outer layers. The layer-wise decomposition of hydrogen bonds and collective single-particle reorientational dynamics reveal a nonmonotonic relaxation pattern with the slowest relaxation observed at the intermediate layers that involves functionally important tertiary motifs. The slowness of this intermediate layer is attributed to two types of long-resident water molecules: (i) water from ion-hydration layers and (ii) structurally trapped water (distant from ions). The relaxation kinetics of the core and the surface water essentially exposed to the phosphate groups show well-separated time scales from the intermediate layers. In the slow intermediate layers, site-specific ions and water control the functional dynamics of important RNA motifs like kink-turn, observed in different structure-probing experiments. Most interestingly, we find that as the size of the RNA core increases (SAM1 core < sfRNAcore < Add adenine core), its hydration tends to show faster relaxation. The hierarchical hydration and the layer-wise base-phosphate composition uniquely portray the globular RNA to act like a soft vesicle with a quasi-dynamic nano-water-pool at its core.
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Affiliation(s)
- Raju Sarkar
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
| | - Rishabh K Singh
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
| | - Susmita Roy
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
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5
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Shin JH, Bonilla SL, Denny SK, Greenleaf WJ, Herschlag D. Dissecting the energetic architecture within an RNA tertiary structural motif via high-throughput thermodynamic measurements. Proc Natl Acad Sci U S A 2023; 120:e2220485120. [PMID: 36897989 PMCID: PMC10243134 DOI: 10.1073/pnas.2220485120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 02/01/2023] [Indexed: 03/12/2023] Open
Abstract
Structured RNAs and RNA/protein complexes perform critical cellular functions. They often contain structurally conserved tertiary contact "motifs," whose occurrence simplifies the RNA folding landscape. Prior studies have focused on the conformational and energetic modularity of intact motifs. Here, we turn to the dissection of one common motif, the 11nt receptor (11ntR), using quantitative analysis of RNA on a massively parallel array to measure the binding of all single and double 11ntR mutants to GAAA and GUAA tetraloops, thereby probing the energetic architecture of the motif. While the 11ntR behaves as a motif, its cooperativity is not absolute. Instead, we uncovered a gradient from high cooperativity amongst base-paired and neighboring residues to additivity between distant residues. As expected, substitutions at residues in direct contact with the GAAA tetraloop resulted in the largest decreases to binding, and energetic penalties of mutations were substantially smaller for binding to the alternate GUAA tetraloop, which lacks tertiary contacts present with the canonical GAAA tetraloop. However, we found that the energetic consequences of base partner substitutions are not, in general, simply described by base pair type or isostericity. We also found exceptions to the previously established stability-abundance relationship for 11ntR sequence variants. These findings of "exceptions to the rule" highlight the power of systematic high-throughput approaches to uncover novel variants for future study in addition to providing an energetic map of a functional RNA.
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Affiliation(s)
- John H. Shin
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA94305
- Department of Chemical Engineering, Stanford University, Stanford, CA94305
| | - Steve L. Bonilla
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Sarah K. Denny
- Department of Genetics, Stanford University School of Medicine, Stanford, CA94305
- Scribe Therapeutics, Alameda, CA94501
| | - William J. Greenleaf
- Department of Genetics, Stanford University School of Medicine, Stanford, CA94305
- Department of Applied Physics, Stanford University, Stanford, CA94305
- Chan Zuckerberg Biohub, San Francisco, CA94158
| | - Daniel Herschlag
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA94305
- Department of Chemical Engineering, Stanford University, Stanford, CA94305
- ChEM-H Institute, Stanford University, Stanford, CA94305
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6
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Chau C, Marcuccio F, Soulias D, Edwards MA, Tuplin A, Radford SE, Hewitt E, Actis P. Probing RNA Conformations Using a Polymer-Electrolyte Solid-State Nanopore. ACS NANO 2022; 16:20075-20085. [PMID: 36279181 PMCID: PMC9798860 DOI: 10.1021/acsnano.2c08312] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Nanopore systems have emerged as a leading platform for the analysis of biomolecular complexes with single-molecule resolution. The conformation of biomolecules, such as RNA, is highly dependent on the electrolyte composition, but solid-state nanopore systems often require high salt concentration to operate, precluding analysis of macromolecular conformations under physiologically relevant conditions. Here, we report the implementation of a polymer-electrolyte solid-state nanopore system based on alkali metal halide salts dissolved in 50% w/v poly(ethylene) glycol (PEG) to augment the performance of our system. We show that polymer-electrolyte bath governs the translocation dynamics of the analyte which correlates with the physical properties of the salt used in the bath. This allowed us to identify CsBr as the optimal salt to complement PEG to generate the largest signal enhancement. Harnessing the effects of the polymer-electrolyte, we probed the conformations of the Chikungunya virus (CHIKV) RNA genome fragments under physiologically relevant conditions. Our system was able to fingerprint CHIKV RNA fragments ranging from ∼300 to ∼2000 nt length and subsequently distinguish conformations between the co-transcriptionally folded and the natively refolded ∼2000 nt CHIKV RNA. We envision that the polymer-electrolyte solid-state nanopore system will further enable structural and conformational analyses of individual biomolecules under physiologically relevant conditions.
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Affiliation(s)
- Chalmers Chau
- School
of Molecular and Cellular Biology and Astbury Centre for Structural
Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K.
- School
of Electronic and Electrical Engineering and Pollard Institute, University of Leeds, Leeds LS2 9JT, U.K.
- Bragg
Centre for Materials Research, University
of Leeds, Leeds LS2 9JT, U.K.
| | - Fabio Marcuccio
- School
of Electronic and Electrical Engineering and Pollard Institute, University of Leeds, Leeds LS2 9JT, U.K.
- Bragg
Centre for Materials Research, University
of Leeds, Leeds LS2 9JT, U.K.
| | - Dimitrios Soulias
- School
of Electronic and Electrical Engineering and Pollard Institute, University of Leeds, Leeds LS2 9JT, U.K.
- Bragg
Centre for Materials Research, University
of Leeds, Leeds LS2 9JT, U.K.
| | - Martin Andrew Edwards
- Department
of Chemistry & Biochemistry, University
of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Andrew Tuplin
- School
of Molecular and Cellular Biology and Astbury Centre for Structural
Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K.
| | - Sheena E. Radford
- School
of Molecular and Cellular Biology and Astbury Centre for Structural
Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K.
| | - Eric Hewitt
- School
of Molecular and Cellular Biology and Astbury Centre for Structural
Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K.
| | - Paolo Actis
- School
of Electronic and Electrical Engineering and Pollard Institute, University of Leeds, Leeds LS2 9JT, U.K.
- Bragg
Centre for Materials Research, University
of Leeds, Leeds LS2 9JT, U.K.
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7
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Liu Z, Thirumalai D. Cooperativity and Folding Kinetics in a Multidomain Protein with Interwoven Chain Topology. ACS CENTRAL SCIENCE 2022; 8:763-774. [PMID: 35756371 PMCID: PMC9228575 DOI: 10.1021/acscentsci.2c00140] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Indexed: 06/15/2023]
Abstract
Although a large percentage of eukaryotic proteomes consist of proteins with multiple domains, not much is known about their assembly mechanism, especially those with intricate native state architectures. Some have a complex topology in which the structural elements along the sequence are interwoven in such a manner that the domains cannot be separated by cutting at any location along the sequence. Such proteins are multiply connected multidomain proteins (MMPs) with the three-domain (NMP, LID, and CORE) phosphotransferase enzyme adenylate kinase (ADK) being an example. We devised a coarse-grained model to simulate ADK folding initiated by changing either the temperature or guanidinium chloride (GdmCl) concentration. The simulations reproduce the experimentally measured melting temperatures (associated with two equilibrium transitions), FRET efficiency as a function of GdmCl concentration, and the folding times quantitatively. Although the NMP domain orders independently, cooperative interactions between the LID and the CORE domains are required for complete assembly of the enzyme. Kinetic simulations show that, on the collapse time scale, multiple interconnected metastable states are populated, attesting to the folding heterogeneity. The network of kinetically connected states reveals that the CORE domain folds only after the NMP and LID domains, reflecting the interwoven nature of the chain topology.
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Affiliation(s)
- Zhenxing Liu
- Department
of Physics, Beijing Normal University, Beijing 100875, China
| | - D. Thirumalai
- Department
of Chemistry, The University of Texas at
Austin, Austin, Texas 78712, United
States
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8
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Kumar S, Reddy G. TPP Riboswitch Populates Holo-Form-like Structure Even in the Absence of Cognate Ligand at High Mg 2+ Concentration. J Phys Chem B 2022; 126:2369-2381. [PMID: 35298161 DOI: 10.1021/acs.jpcb.1c10794] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Riboswitches are noncoding RNA that regulate gene expression by folding into specific three-dimensional structures (holo-form) upon binding by their cognate ligand in the presence of Mg2+. Riboswitch functioning is also hypothesized to be under kinetic control requiring large cognate ligand concentrations. We ask the question under thermodynamic conditions, can the riboswitches populate structures similar to the holo-form only in the presence of Mg2+ and absence of cognate ligand binding. We addressed this question using thiamine pyrophosphate (TPP) riboswitch as a model system and computer simulations using a coarse-grained model for RNA. The folding free energy surface (FES) shows that with the initial increase in Mg2+ concentration ([Mg2+]), the aptamer domain (AD) of TPP riboswitch undergoes a barrierless collapse in its dimensions. On further increase in [Mg2+], intermediates separated by barriers appear on the FES, and one of the intermediates has a TPP ligand-binding competent structure. We show that site-specific binding of the Mg2+ aids in the formation of tertiary contacts. For [Mg2+] greater than physiological concentration, AD folds into a structure similar to the crystal structure of the TPP holo-form even in the absence of the TPP ligand. The folding kinetics shows that TPP AD populates an intermediate due to the misalignment of two arms present in the structure, which acts as a kinetic trap, leading to larger folding timescales. The predictions of the intermediate structures from the simulations are amenable for experimental verification.
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Affiliation(s)
- Sunil Kumar
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Govardhan Reddy
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru, Karnataka 560012, India
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9
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Pseudoknot length modulates the folding, conformational dynamics, and robustness of Xrn1 resistance of flaviviral xrRNAs. Nat Commun 2021; 12:6417. [PMID: 34741027 PMCID: PMC8571300 DOI: 10.1038/s41467-021-26616-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 10/04/2021] [Indexed: 01/15/2023] Open
Abstract
To understand how RNA dynamics is regulated and connected to its function, we investigate the folding, conformational dynamics and robustness of Xrn1 resistance of a set of flaviviral xrRNAs using SAXS, smFRET and in vitro enzymatic assays. Flaviviral xrRNAs form discrete ring-like 3D structures, in which the length of a conserved long-range pseudoknot (PK2) ranges from 2 bp to 7 bp. We find that xrRNAs' folding, conformational dynamics and Xrn1 resistance are strongly correlated and highly Mg2+-dependent, furthermore, the Mg2+-dependence is modulated by PK2 length variations. xrRNAs with long PK2 require less Mg2+ to stabilize their folding, exhibit reduced conformational dynamics and strong Xrn1 resistance even at low Mg2+, and tolerate mutations at key tertiary motifs at high Mg2+, which generally are destructive to xrRNAs with short PK2. These results demonstrate an unusual regulatory mechanism of RNA dynamics providing insights into the functions and future biomedical applications of xrRNAs.
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10
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Villarreal LP, Witzany G. Social Networking of Quasi-Species Consortia drive Virolution via Persistence. AIMS Microbiol 2021; 7:138-162. [PMID: 34250372 PMCID: PMC8255905 DOI: 10.3934/microbiol.2021010] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 04/25/2021] [Indexed: 12/31/2022] Open
Abstract
The emergence of cooperative quasi-species consortia (QS-C) thinking from the more accepted quasispecies equations of Manfred Eigen, provides a conceptual foundation from which concerted action of RNA agents can now be understood. As group membership becomes a basic criteria for the emergence of living systems, we also start to understand why the history and context of social RNA networks become crucial for survival and function. History and context of social RNA networks also lead to the emergence of a natural genetic code. Indeed, this QS-C thinking can also provide us with a transition point between the chemical world of RNA replicators and the living world of RNA agents that actively differentiate self from non-self and generate group identity with membership roles. Importantly the social force of a consortia to solve complex, multilevel problems also depend on using opposing and minority functions. The consortial action of social networks of RNA stem-loops subsequently lead to the evolution of cellular organisms representing a tree of life.
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11
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Thompson MK, Kiourlappou M, Davis I. Ribo-Pop: simple, cost-effective, and widely applicable ribosomal RNA depletion. RNA (NEW YORK, N.Y.) 2020; 26:1731-1742. [PMID: 32759389 PMCID: PMC7566562 DOI: 10.1261/rna.076562.120] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/31/2020] [Indexed: 06/11/2023]
Abstract
The measurement of RNA abundance derived from massively parallel sequencing experiments is an essential technique. Methods that reduce ribosomal RNA levels are usually required prior to sequencing library construction because ribosomal RNA typically comprises the vast majority of a total RNA sample. For some experiments, ribosomal RNA depletion is favored over poly(A) selection because it offers a more inclusive representation of the transcriptome. However, methods to deplete ribosomal RNA are generally proprietary, complex, inefficient, applicable to only specific species, or compatible with only a narrow range of RNA input levels. Here, we describe Ribo-Pop (ribosomal RNA depletion for popular use), a simple workflow and antisense oligo design strategy that we demonstrate works over a wide input range and can be easily adapted to any organism with a sequenced genome. We provide a computational pipeline for probe selection, a streamlined 20-min protocol, and ready-to-use oligo sequences for several organisms. We anticipate that our simple and generalizable "open source" design strategy would enable virtually any laboratory to pursue full transcriptome sequencing in their organism of interest with minimal time and resource investment.
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Affiliation(s)
- Mary Kay Thompson
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
| | - Maria Kiourlappou
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
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12
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Xu X, Chen SJ. Topological constraints of RNA pseudoknotted and loop-kissing motifs: applications to three-dimensional structure prediction. Nucleic Acids Res 2020; 48:6503-6512. [PMID: 32491164 PMCID: PMC7337929 DOI: 10.1093/nar/gkaa463] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 05/19/2020] [Indexed: 01/23/2023] Open
Abstract
An RNA global fold can be described at the level of helix orientations and relatively flexible loop conformations that connect the helices. The linkage between the helices plays an essential role in determining the structural topology, which restricts RNA local and global folds, especially for RNA tertiary structures involving cross-linked base pairs. We quantitatively analyze the topological constraints on RNA 3D conformational space, in particular, on the distribution of helix orientations, for pseudoknots and loop-loop kissing structures. The result shows that a viable conformational space is predominantly determined by the motif type, helix size, and loop size, indicating a strong topological coupling between helices and loops in RNA tertiary motifs. Moreover, the analysis indicates that (cross-linked) tertiary contacts can cause much stronger topological constraints on RNA global fold than non-cross-linked base pairs. Furthermore, based on the topological constraints encoded in the 2D structure and the 3D templates, we develop a 3D structure prediction approach. This approach can be further combined with structure probing methods to expand the capability of computational prediction for large RNA folds.
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Affiliation(s)
- Xiaojun Xu
- Institute of Bioinformatics and Medical Engineering, Jiangsu University of Technology, Changzhou, Jiangsu 213001, China
| | - Shi-Jie Chen
- Department of Physics, Department of Biochemistry, and Informatics Institute, University of Missouri, Columbia, MO 65211, USA
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13
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Modeling Loop Composition and Ion Concentration Effects in RNA Hairpin Folding Stability. Biophys J 2020; 119:1439-1455. [PMID: 32949490 DOI: 10.1016/j.bpj.2020.07.042] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/12/2020] [Accepted: 07/08/2020] [Indexed: 12/21/2022] Open
Abstract
The ability to accurately predict RNA hairpin structure and stability for different loop sequences and salt conditions is important for understanding, modeling, and designing larger RNA folds. However, traditional RNA secondary structure models cannot treat loop-sequence and ionic effects on RNA hairpin folding. Here, we describe a general, three-dimensional (3D) conformation-based computational method for modeling salt concentration-dependent conformational distributions and the detailed 3D structures for a set of three RNA hairpins that contain a variable, 15-nucleotide loop sequence. For a given RNA sequence, the new, to our knowledge, method integrates a Vfold2D two-dimensional structure folding model with IsRNA coarse-grained molecular dynamics 3D folding simulations and Monte Carlo tightly bound ion estimations of ion-mediated electrostatic interactions. The model predicts free-energy landscapes for the different RNA hairpin-forming sequences with variable salt conditions. The theoretically predicted results agree with the experimental fluorescence measurements, validating the strategy. Furthermore, the theoretical model goes beyond the experimental results by enabling in-depth 3D structural analysis, revealing energetic mechanisms for the sequence- and salt-dependent folding stability. Although the computational framework presented here is developed for RNA hairpin systems, the general method may be applied to investigate other RNA systems, such as multiway junctions or pseudoknots in mixed metal ion solutions.
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14
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Mitchell C, Polanco JA, DeWald L, Kress D, Jaeger L, Grabow WW. Responsive self-assembly of tectoRNAs with loop-receptor interactions from the tetrahydrofolate (THF) riboswitch. Nucleic Acids Res 2020; 47:6439-6451. [PMID: 31045210 PMCID: PMC6614920 DOI: 10.1093/nar/gkz304] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 03/22/2019] [Accepted: 04/16/2019] [Indexed: 12/17/2022] Open
Abstract
Naturally occurring RNAs are known to exhibit a high degree of modularity, whereby specific structural modules (or motifs) can be mixed and matched to create new molecular architectures. The modular nature of RNA also affords researchers the ability to characterize individual structural elements in controlled synthetic contexts in order to gain new and critical insights into their particular structural features and overall performance. Here, we characterized the binding affinity of a unique loop–receptor interaction found in the tetrahydrofolate (THF) riboswitch using rationally designed self-assembling tectoRNAs. Our work suggests that the THF loop–receptor interaction has been fine-tuned for its particular role as a riboswitch component. We also demonstrate that the thermodynamic stability of this interaction can be modulated by the presence of folinic acid, which induces a local structural change at the level of the loop–receptor. This corroborates the existence of a THF binding site within this tertiary module and paves the way for its potential use as a THF responsive module for RNA nanotechnology and synthetic biology.
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Affiliation(s)
- Charles Mitchell
- Department of Chemistry and Biochemistry, Seattle Pacific University, Seattle, WA 918119-1997, USA
| | - Julio A Polanco
- Department of Chemistry and Biochemistry, Biomolecular Science and Engineering Program, University of California, Santa Barbara, CA 93106-9510, USA
| | - Laura DeWald
- Department of Chemistry and Biochemistry, Seattle Pacific University, Seattle, WA 918119-1997, USA
| | - Dustin Kress
- Department of Chemistry and Biochemistry, Seattle Pacific University, Seattle, WA 918119-1997, USA
| | - Luc Jaeger
- Department of Chemistry and Biochemistry, Biomolecular Science and Engineering Program, University of California, Santa Barbara, CA 93106-9510, USA
| | - Wade W Grabow
- Department of Chemistry and Biochemistry, Seattle Pacific University, Seattle, WA 918119-1997, USA
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15
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Grabow WW, Andrews GE. On the nature and origin of biological information: The curious case of RNA. Biosystems 2019; 185:104031. [PMID: 31525398 DOI: 10.1016/j.biosystems.2019.104031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 09/11/2019] [Accepted: 09/12/2019] [Indexed: 11/18/2022]
Abstract
Biological information is most commonly thought of in terms of biology's Central Dogma where DNA is viewed as a linearized code used to synthesize proteins. Using DNA's chemical cousin, RNA, as a case study we consider how biological information operates outside the linear arrangement of its polymeric subunits. Much like individual pieces of a jigsaw puzzle, particular structures enable biomolecules to undergo precise molecular interactions with one another based on their respective shapes. By exploring the relationship between sequence and structure in RNA we argue that biological information finds its ultimate functional fulfillment in the three-dimensional structural arrangement of its atoms. We show how recurrent structural RNA motifs-operating at the tertiary level of a molecule-provide robust building blocks for the formation of new structural configurations and thereby convey the information required for emergent biological functions. We posit that these same RNA structures, guided by their respective thermodynamic stabilities, experience selective pressure to maintain particular three-dimensional architectures over and above pressures to maintain a particular sequence of nucleotides. Ultimately, this framework for understanding the nature of biological information provides a useful paradigm for understanding its origins and how biological information can result from chaotic prebiotic conditions.
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Affiliation(s)
- Wade W Grabow
- Department of Chemistry and Biochemistry, Seattle Pacific University, Seattle, WA, 918119-1997, USA.
| | - Grace E Andrews
- Department of Chemistry and Biochemistry, Seattle Pacific University, Seattle, WA, 918119-1997, USA
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16
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Brosey CA, Tainer JA. Evolving SAXS versatility: solution X-ray scattering for macromolecular architecture, functional landscapes, and integrative structural biology. Curr Opin Struct Biol 2019; 58:197-213. [PMID: 31204190 PMCID: PMC6778498 DOI: 10.1016/j.sbi.2019.04.004] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 04/10/2019] [Accepted: 04/15/2019] [Indexed: 11/27/2022]
Abstract
Small-angle X-ray scattering (SAXS) has emerged as an enabling
integrative technique for comprehensive analyses of macromolecular structures
and interactions in solution. Over the past two decades, SAXS has become a
mainstay of the structural biologist’s toolbox, supplying multiplexed
measurements of molecular shape and dynamics that unveil biological function.
Here, we discuss evolving SAXS theory, methods, and applications that extend the
field of small-angle scattering beyond simple shape characterization. SAXS,
coupled with size-exclusion chromatography (SEC-SAXS) and time-resolved
(TR-SAXS) methods, is now providing high-resolution insight into macromolecular
flexibility and ensembles, delineating biophysical landscapes, and facilitating
high-throughput library screening to assess macromolecular properties and to
create opportunities for drug discovery. Looking forward, we consider SAXS in
the integrative era of hybrid structural biology methods, its potential for
illuminating cellular supramolecular and mesoscale structures, and its capacity
to complement high-throughput bioinformatics sequencing data. As advances in the
field continue, we look forward to proliferating uses of SAXS based upon its
abilities to robustly produce mechanistic insights for biology and medicine.
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Affiliation(s)
- Chris A Brosey
- Molecular and Cellular Oncology and Cancer Biology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
| | - John A Tainer
- Molecular and Cellular Oncology and Cancer Biology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA; MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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17
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Umuhire Juru A, Patwardhan NN, Hargrove AE. Understanding the Contributions of Conformational Changes, Thermodynamics, and Kinetics of RNA-Small Molecule Interactions. ACS Chem Biol 2019; 14:824-838. [PMID: 31042354 DOI: 10.1021/acschembio.8b00945] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The implication of RNA in multiple cellular processes beyond protein coding has revitalized interest in the development of small molecules for therapeutically targeting RNA and for further probing its cellular biology. However, the process of rationally designing such small molecule probes is hampered by the paucity of information about fundamental molecular recognition principles of RNA. In this Review, we summarize two important and often underappreciated aspects of RNA-small molecule recognition: RNA conformational dynamics and the biophysical properties of interactions of small molecules with RNA, specifically thermodynamics and kinetics. While conformational flexibility is often said to impede RNA ligand development, the ability of small molecules to influence the RNA conformational landscape can have a significant effect on the cellular functions of RNA. An analysis of the conformational landscape of RNA and the interactions of individual conformations with ligands can thus guide the development of new small molecule probes, which needs to be investigated further. Additionally, while it is common practice to quantify the binding affinities ( Ka or Kd) of small molecules for biomacromolecules as a measure of their activity, further biophysical characterization of their interaction can provide a deeper understanding. Studies that focus on the thermodynamic and kinetic parameters for interaction between RNA and ligands are next discussed. Finally, this Review provides the reader with a perspective on how such in-depth analysis of biophysical characteristics of the interaction of RNA and small molecules can impact our understanding of these interactions and how they will benefit the future design of small molecule probes.
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Affiliation(s)
- Aline Umuhire Juru
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Neeraj N. Patwardhan
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Amanda E. Hargrove
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
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18
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Hori N, Denesyuk NA, Thirumalai D. Ion Condensation onto Ribozyme Is Site Specific and Fold Dependent. Biophys J 2019; 116:2400-2410. [PMID: 31130233 DOI: 10.1016/j.bpj.2019.04.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/12/2019] [Accepted: 04/23/2019] [Indexed: 01/20/2023] Open
Abstract
The highly charged RNA molecules, with each phosphate carrying a single negative charge, cannot fold into well-defined architectures with tertiary interactions in the absence of ions. For ribozymes, divalent cations are known to be more efficient than monovalent ions in driving them to a compact state, although Mg2+ ions are needed for catalytic activities. Therefore, how ions interact with RNA is relevant in understanding RNA folding. It is often thought that most of the ions are territorially and nonspecifically bound to the RNA, as predicted by the counterion condensation theory. Here, we show using simulations of Azoarcus ribozyme, based on an accurate coarse-grained three-site interaction model with explicit divalent and monovalent cations, that ion condensation is highly specific and depends on the nucleotide position. The regions with high coordination between the phosphate groups and the divalent cations are discernible even at very low Mg2+ concentrations when the ribozyme does not form tertiary interactions. Surprisingly, these regions also contain the secondary structural elements that nucleate subsequently in the self-assembly of RNA, implying that ion condensation is determined by the architecture of the folded state. These results are in sharp contrast to interactions of ions (monovalent and divalent) with rigid charged rods, in which ion condensation is uniform and position independent. The differences are explained in terms of the dramatic nonmonotonic shape fluctuations in the ribozyme as it folds with increasing Mg2+ or Ca2+ concentration.
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Affiliation(s)
- Naoto Hori
- Department of Chemistry, University of Texas, Austin, Texas
| | - Natalia A Denesyuk
- Biophysics Program, Institute for Physical Science and Technology, University of Maryland, College Park, Maryland
| | - D Thirumalai
- Department of Chemistry, University of Texas, Austin, Texas.
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19
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Yamasaki S, Amemiya T, Yabuki Y, Horimoto K, Fukui K. ToGo-WF: prediction of RNA tertiary structures and RNA-RNA/protein interactions using the KNIME workflow. J Comput Aided Mol Des 2019; 33:497-507. [PMID: 30840170 PMCID: PMC7088279 DOI: 10.1007/s10822-019-00195-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 02/28/2019] [Indexed: 12/22/2022]
Abstract
Recent progress in molecular biology has revealed that many non-coding RNAs regulate gene expression or catalyze biochemical reactions in tumors, viruses and several other diseases. The tertiary structure of RNA molecules and RNA–RNA/protein interaction sites are of increasing importance as potential targets for new medicines that treat a broad array of human diseases. Current RNA drugs are split into two groups: antisense RNA molecules and aptamers. In this report, we present a novel workflow to predict RNA tertiary structures and RNA–RNA/protein interactions using the KNIME environment, which enabled us to assemble a combination of RNA-related analytical tools and databases. In this study, three analytical workflows for comprehensive structural analysis of RNA are introduced: (1) prediction of the tertiary structure of RNA; (2) prediction of the structure of RNA–RNA complexes and analysis of their interactions; and (3) prediction of the structure of RNA–protein complexes and analysis of their interactions. In an RNA–protein case study, we modeled the tertiary structure of pegaptanib, an aptamer drug, and performed docking calculations of the pegaptanib-vascular endothelial growth factor complex using a fragment of the interaction site of the aptamer. We also present molecular dynamics simulations of the RNA–protein complex to evaluate the affinity of the complex by mutating bases at the interaction interface. The results provide valuable information for designing novel features of aptamer-protein complexes.
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Affiliation(s)
- Satoshi Yamasaki
- Molecular Profiling for Drug Discovery Research Center (molprof), National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan. .,Laboratory of Molecular Medicine, Human Genome Center, The Institute of Medical Science, The University of Tokyo (IMSUT), 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan.
| | - Takayuki Amemiya
- Molecular Profiling for Drug Discovery Research Center (molprof), National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan
| | - Yukimitsu Yabuki
- Molecular Profiling for Drug Discovery Research Center (molprof), National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan.,IMSBIO Co., Ltd, 4-21-1-601 Higashi-Ikebukuro, Toshima-ku, Tokyo, 170-0013, Japan
| | - Katsuhisa Horimoto
- Molecular Profiling for Drug Discovery Research Center (molprof), National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan
| | - Kazuhiko Fukui
- Molecular Profiling for Drug Discovery Research Center (molprof), National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan.
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20
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Abstract
RNA-binding proteins chaperone the biological functions of noncoding RNA by reducing RNA misfolding, improving matchmaking between regulatory RNA and targets, and exerting quality control over RNP biogenesis. Recent studies of Escherichia coli CspA, HIV NCp, and E. coli Hfq are beginning to show how RNA-binding proteins remodel RNA structures. These different protein families use common strategies for disrupting or annealing RNA double helices, which can be used to understand the mechanisms by which proteins chaperone RNA-dependent regulation in bacteria.
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21
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Welty R, Pabit SA, Katz AM, Calvey GD, Pollack L, Hall KB. Divalent ions tune the kinetics of a bacterial GTPase center rRNA folding transition from secondary to tertiary structure. RNA (NEW YORK, N.Y.) 2018; 24:1828-1838. [PMID: 30254137 PMCID: PMC6239185 DOI: 10.1261/rna.068361.118] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 09/20/2018] [Indexed: 05/22/2023]
Abstract
Folding of an RNA from secondary to tertiary structure often depends on divalent ions for efficient electrostatic charge screening (nonspecific association) or binding (specific association). To measure how different divalent cations modify folding kinetics of the 60 nucleotide Ecoli rRNA GTPase center, we combined stopped-flow fluorescence in the presence of Mg2+, Ca2+, or Sr2+ together with time-resolved small angle X-ray scattering (SAXS) in the presence of Mg2+ to observe the folding process. Immediately upon addition of each divalent ion, the RNA undergoes a transition from an extended state with secondary structure to a more compact structure. Subsequently, specific divalent ions modulate populations of intermediates in conformational ensembles along the folding pathway with transition times longer than 10 msec. Rate constants for the five folding transitions act on timescales from submillisecond to tens of seconds. The sensitivity of RNA tertiary structure to divalent cation identity affects all but the fastest events in RNA folding, and allowed us to identify those states that prefer Mg2+ The GTPase center RNA appears to have optimized its folding trajectory to specifically utilize this most abundant intracellular divalent ion.
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Affiliation(s)
- Robb Welty
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Suzette A Pabit
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Andrea M Katz
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - George D Calvey
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Kathleen B Hall
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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22
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Plumridge A, Katz AM, Calvey GD, Elber R, Kirmizialtin S, Pollack L. Revealing the distinct folding phases of an RNA three-helix junction. Nucleic Acids Res 2018; 46:7354-7365. [PMID: 29762712 PMCID: PMC6101490 DOI: 10.1093/nar/gky363] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/17/2018] [Accepted: 04/24/2018] [Indexed: 01/08/2023] Open
Abstract
Remarkable new insight has emerged into the biological role of RNA in cells. RNA folding and dynamics enable many of these newly discovered functions, calling for an understanding of RNA self-assembly and conformational dynamics. Because RNAs pass through multiple structures as they fold, an ensemble perspective is required to visualize the flow through fleetingly populated sets of states. Here, we combine microfluidic mixing technology and small angle X-ray scattering (SAXS) to measure the Mg-induced folding of a small RNA domain, the tP5abc three helix junction. Our measurements are interpreted using ensemble optimization to select atomically detailed structures that recapitulate each experimental curve. Structural ensembles, derived at key stages in both time-resolved studies and equilibrium titrations, reproduce the features of known intermediates, and more importantly, offer a powerful new structural perspective on the time-progression of folding. Distinct collapse phases along the pathway appear to be orchestrated by specific interactions with Mg ions. These key interactions subsequently direct motions of the backbone that position the partners of tertiary contacts for later bonding, and demonstrate a remarkable synergy between Mg and RNA across numerous time-scales.
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Affiliation(s)
- Alex Plumridge
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Andrea M Katz
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - George D Calvey
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Ron Elber
- Department of Chemistry and Institute for Computational Engineering and Sciences (ICES) University of Texas at Austin, Austin, TX, USA
| | - Serdal Kirmizialtin
- Chemistry Program, Science Division, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
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23
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Abstract
Nanomedicine is a discipline that applies nanoscience and nanotechnology principles to the prevention, diagnosis, and treatment of human diseases. Self-assembly of molecular components is becoming a common strategy in the design and syntheses of nanomaterials for biomedical applications. In both natural and synthetic self-assembled nanostructures, molecular cooperativity is emerging as an important hallmark. In many cases, interplay of many types of noncovalent interactions leads to dynamic nanosystems with emergent properties where the whole is bigger than the sum of the parts. In this review, we provide a comprehensive analysis of the cooperativity principles in multiple self-assembled nanostructures. We discuss the molecular origin and quantitative modeling of cooperative behaviors. In selected systems, we describe the examples on how to leverage molecular cooperativity to design nanomedicine with improved diagnostic precision and therapeutic efficacy in medicine.
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Affiliation(s)
- Yang Li
- Department of Pharmacology, Simmons Comprehensive Cancer Center , UT Southwestern Medical Center , 5323 Harry Hines Boulevard , Dallas , Texas 75390 , United States
| | - Yiguang Wang
- Department of Pharmacology, Simmons Comprehensive Cancer Center , UT Southwestern Medical Center , 5323 Harry Hines Boulevard , Dallas , Texas 75390 , United States.,Beijing Key Laboratory of Molecular Pharmaceutics and State Key Laboratory of Natural and Biomimetic Drugs , Peking University , Beijing , 100191 , China
| | - Gang Huang
- Department of Pharmacology, Simmons Comprehensive Cancer Center , UT Southwestern Medical Center , 5323 Harry Hines Boulevard , Dallas , Texas 75390 , United States
| | - Jinming Gao
- Department of Pharmacology, Simmons Comprehensive Cancer Center , UT Southwestern Medical Center , 5323 Harry Hines Boulevard , Dallas , Texas 75390 , United States
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24
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Zhen JP, Wei XC, Shi WJ, Huang ZY, Jin B, Zhou YK. Cooperativity effect involving drug-DNA/RNA intermolecular interaction: A B3LYP-D3 and MP2 theoretical investigation on ketoprofen⋯cytosine⋯H 2O system. J Biomol Struct Dyn 2017; 36:3587-3606. [PMID: 29092677 DOI: 10.1080/07391102.2017.1400469] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In order to examine the origin of the drug action and design new DNA/RNA-targeted drugs, the cooperativity effect involving drug-DNA/RNA intermolecular interaction in ketoprofen⋯cytosine⋯H2O ternary system were investigated by the B3LYP, B3LYP-D3, and MP2 methods with the 6-311++G(2d,p) basis set. The thermodynamic cooperativity was also evaluated at 310.15 K. The N-H⋯O, O-H⋯O, O-H⋯N, C-H⋯N, and C-H⋯O H bonds coexist in ternary complexes. The intermolecular interactions obtained by B3LYP-D3 are close to those calculated by MP2. The steric effects and van der Waals interactions have little influence on the cooperativity effects. The anti-cooperativity effect in ket⋯cyt⋯H2O is far more notable than the cooperativity effect, and the stability of the cyclic structure with anti-cooperativity effect is higher than that of the linear structure with cooperativity effect, as is confirmed by the AIM (atoms in molecules) and RDG (reduced density gradient) analysis. Thus, it can be inferred that, in the presence of H2O, the anti-cooperativity effect plays a dominant role in the drug-DNA/RNA interaction, and the nature of the hydration in the binding of drugs to DNA/RNA bases is the H-bonding anti-cooperativity effect. Furthermore, the drug always links simultaneously with DNA/RNA base and H2O, and only in this way can the biological activity of drugs play a role. In most cases, the enthalpy change is the major factor driving the cooperativity, as is different from most of biomacromolecule complexes.
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Affiliation(s)
- Jun-Ping Zhen
- a Molecular Imaging Laboratory, Department of Radiology , The Second Hospital of Shanxi Medical University , Taiyuan 030053 , China
| | - Xiao-Chun Wei
- a Molecular Imaging Laboratory, Department of Radiology , The Second Hospital of Shanxi Medical University , Taiyuan 030053 , China
| | - Wen-Jing Shi
- a Molecular Imaging Laboratory, Department of Radiology , The Second Hospital of Shanxi Medical University , Taiyuan 030053 , China
| | - Zhu-Yuan Huang
- a Molecular Imaging Laboratory, Department of Radiology , The Second Hospital of Shanxi Medical University , Taiyuan 030053 , China
| | - Bo Jin
- a Molecular Imaging Laboratory, Department of Radiology , The Second Hospital of Shanxi Medical University , Taiyuan 030053 , China
| | - Yu-Kun Zhou
- a Molecular Imaging Laboratory, Department of Radiology , The Second Hospital of Shanxi Medical University , Taiyuan 030053 , China
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25
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Schlick T, Pyle AM. Opportunities and Challenges in RNA Structural Modeling and Design. Biophys J 2017; 113:225-234. [PMID: 28162235 PMCID: PMC5529161 DOI: 10.1016/j.bpj.2016.12.037] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 12/08/2016] [Accepted: 12/19/2016] [Indexed: 01/27/2023] Open
Abstract
We describe opportunities and challenges in RNA structural modeling and design, as recently discussed during the second Telluride Science Research Center workshop organized in June 2016. Topics include fundamental processes of RNA, such as structural assemblies (hierarchical folding, multiple conformational states and their clustering), RNA motifs, and chemical reactivity of RNA, as used for structural prediction and functional inference. We also highlight the software and database issues associated with RNA structures, such as the multiple approaches for motif annotation, the need for frequent database updating, and the importance of quality control of RNA structures. We discuss various modeling approaches for structure prediction, mechanistic analysis of RNA reactions, and RNA design, and the complementary roles that both atomistic and coarse-grained approaches play in such simulations. Collectively, as scientists from varied disciplines become familiar and drawn into these unique challenges, new approaches and collaborative efforts will undoubtedly be catalyzed.
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Affiliation(s)
- Tamar Schlick
- Department of Chemistry, New York University, New York, New York; Courant Institute of Mathematical Sciences, New York University, New York, New York.
| | - Anna Marie Pyle
- Department of Molecular and Cellular and Developmental Biology and Department of Chemistry, Yale University; Howard Hughes Medical Institute, New Haven, Connecticut.
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26
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Leamy KA, Yennawar NH, Bevilacqua PC. Cooperative RNA Folding under Cellular Conditions Arises From Both Tertiary Structure Stabilization and Secondary Structure Destabilization. Biochemistry 2017; 56:3422-3433. [PMID: 28657303 DOI: 10.1021/acs.biochem.7b00325] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
RNA folding has been studied extensively in vitro, typically under dilute solution conditions and abiologically high salt concentrations of 1 M Na+ or 10 mM Mg2+. The cellular environment is very different, with 20-40% crowding and only 10-40 mM Na+, 140 mM K+, and 0.5-2.0 mM Mg2+. As such, RNA structures and functions can be radically altered under cellular conditions. We previously reported that tRNAphe secondary and tertiary structures unfold together in a cooperative two-state fashion under crowded in vivo-like ionic conditions, but in a noncooperative multistate fashion under dilute in vitro ionic conditions unless in nonphysiologically high concentrations of Mg2+. The mechanistic basis behind these effects remains unclear, however. To address the mechanism that drives RNA folding cooperativity, we probe effects of cellular conditions on structures and stabilities of individual secondary structure fragments comprising the full-length RNA. We elucidate effects of a diverse set of crowders on tRNA secondary structural fragments and full-length tRNA at three levels: at the nucleotide level by temperature-dependent in-line probing, at the tertiary structure level by small-angle X-ray scattering, and at the global level by thermal denaturation. We conclude that cooperative RNA folding is induced by two overlapping mechanisms: increased stability and compaction of tertiary structure through effects of Mg2+, and decreased stability of certain secondary structure elements through the effects of molecular crowders. These findings reveal that despite having very different chemical makeups RNA and protein can both have weak secondary structures in vivo leading to cooperative folding.
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Affiliation(s)
- Kathleen A Leamy
- Department of Chemistry, ‡Center for RNA Molecular Biology, §Huck Institutes of the Life Sciences, and ⊥Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Neela H Yennawar
- Department of Chemistry, ‡Center for RNA Molecular Biology, §Huck Institutes of the Life Sciences, and ⊥Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Philip C Bevilacqua
- Department of Chemistry, ‡Center for RNA Molecular Biology, §Huck Institutes of the Life Sciences, and ⊥Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
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27
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Vušurović N, Altman RB, Terry DS, Micura R, Blanchard SC. Pseudoknot Formation Seeds the Twister Ribozyme Cleavage Reaction Coordinate. J Am Chem Soc 2017; 139:8186-8193. [PMID: 28598157 PMCID: PMC5697751 DOI: 10.1021/jacs.7b01549] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The twister RNA is a recently discovered nucleolytic ribozyme that is present in both bacteria and eukarya. While its biological role remains unclear, crystal structure analyses and biochemical approaches have revealed critical features of its catalytic mechanism. Here, we set out to explore dynamic aspects of twister RNA folding along the cleavage reaction coordinate. To do so, we have employed both bulk and single-molecule fluorescence resonance energy transfer (FRET) methods to investigate a set of twister RNAs with labels strategically positioned at communicating segments. The data reveal that folding of the central pseudoknot (T1), the most crucial structural determinant to promote cleavage, exhibits reversible opening and closing dynamics at physiological Mg2+ concentration. Uncoupled folding, in which T1 formation precedes structuring for closing of stem P1, was confirmed using pre-steady-state three-color smFRET experiments initiated by Mg2+ injection. This finding suggests that the folding path of twister RNA requires proper orientation of the substrate prior to T1 closure such that the U5-A6 cleavage site becomes embraced to achieve its cleavage competent conformation. We also find that the cleaved 3'-fragment retains its compacted pseudoknot fold, despite the absence of the phylogenetically conserved stem P1, rationalizing the poor turnover efficiency of the twister ribozyme.
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Affiliation(s)
- Nikola Vušurović
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Roger B. Altman
- Weill Cornell Medicine, New York, New York 10065, United States
| | - Daniel S. Terry
- Weill Cornell Medicine, New York, New York 10065, United States
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
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28
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Samanta HS, Zhuravlev PI, Hinczewski M, Hori N, Chakrabarti S, Thirumalai D. Protein collapse is encoded in the folded state architecture. SOFT MATTER 2017; 13:3622-3638. [PMID: 28447708 DOI: 10.1039/c7sm00074j] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Folded states of single domain globular proteins are compact with high packing density. The radius of gyration, Rg, of both the folded and unfolded states increase as Nν where N is the number of amino acids in the protein. The values of the Flory exponent ν are, respectively, ≈⅓ and ≈0.6 in the folded and unfolded states, coinciding with those for homopolymers. However, the extent of compaction of the unfolded state of a protein under low denaturant concentration (collapsibility), conditions favoring the formation of the folded state, is unknown. We develop a theory that uses the contact map of proteins as input to quantitatively assess collapsibility of proteins. Although collapsibility is universal, the propensity to be compact depends on the protein architecture. Application of the theory to over two thousand proteins shows that collapsibility depends not only on N but also on the contact map reflecting the native structure. A major prediction of the theory is that β-sheet proteins are far more collapsible than structures dominated by α-helices. The theory and the accompanying simulations, validating the theoretical predictions, provide insights into the differing conclusions reached using different experimental probes assessing the extent of compaction of proteins. By calculating the criterion for collapsibility as a function of protein length we provide quantitative insights into the reasons why single domain proteins are small and the physical reasons for the origin of multi-domain proteins. Collapsibility of non-coding RNA molecules is similar β-sheet proteins structures adding support to "Compactness Selection Hypothesis".
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Affiliation(s)
- Himadri S Samanta
- Department of Chemistry, University of Texas at Austin, TX 78712, USA.
| | - Pavel I Zhuravlev
- Biophysics Program, Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA
| | | | - Naoto Hori
- Department of Chemistry, University of Texas at Austin, TX 78712, USA.
| | - Shaon Chakrabarti
- Biophysics Program, Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA
| | - D Thirumalai
- Department of Chemistry, University of Texas at Austin, TX 78712, USA. and Biophysics Program, Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA
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Design and Experimental Evolution of trans-Splicing Group I Intron Ribozymes. Molecules 2017; 22:molecules22010075. [PMID: 28045452 PMCID: PMC6155759 DOI: 10.3390/molecules22010075] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/27/2016] [Accepted: 12/29/2016] [Indexed: 12/31/2022] Open
Abstract
Group I intron ribozymes occur naturally as cis-splicing ribozymes, in the form of introns that do not require the spliceosome for their removal. Instead, they catalyze two consecutive trans-phosphorylation reactions to remove themselves from a primary transcript, and join the two flanking exons. Designed, trans-splicing variants of these ribozymes replace the 3′-portion of a substrate with the ribozyme’s 3′-exon, replace the 5′-portion with the ribozyme’s 5′-exon, or insert/remove an internal sequence of the substrate. Two of these designs have been evolved experimentally in cells, leading to variants of group I intron ribozymes that splice more efficiently, recruit a cellular protein to modify the substrate’s gene expression, or elucidate evolutionary pathways of ribozymes in cells. Some of the artificial, trans-splicing ribozymes are promising as tools in therapy, and as model systems for RNA evolution in cells. This review provides an overview of the different types of trans-splicing group I intron ribozymes that have been generated, and the experimental evolution systems that have been used to improve them.
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Welty R, Hall KB. Nucleobases Undergo Dynamic Rearrangements during RNA Tertiary Folding. J Mol Biol 2016; 428:4490-4502. [PMID: 27693721 DOI: 10.1016/j.jmb.2016.09.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 08/31/2016] [Accepted: 09/15/2016] [Indexed: 02/07/2023]
Abstract
The tertiary structure of the GTPase center (GAC) of 23S ribosomal RNA (rRNA) as seen in cocrystals is extremely compact. It is stabilized by long-range hydrogen bonds and nucleobase stacking and by a triloop that forms within its three-way junction. Its folding pathway from secondary structure to tertiary structure has not been previously observed, but it was shown to require Mg2+ ions in equilibrium experiments. The fluorescent nucleotide 2-aminopurine was substituted at selected sites within the 60-nt GAC. Fluorescence intensity changes upon addition of MgCl2 were monitored over a time-course from 1ms to 100s as the RNA folds. The folding pathway is revealed here to be hierarchical through several intermediates. Observation of the nucleobases during folding provides a new perspective on the process and the pathway, revealing the dynamics of nucleobase conformational exchange during the folding transitions.
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Affiliation(s)
- Robb Welty
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Kathleen B Hall
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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31
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Paul R, Greenberg MM. Mechanistic Studies on RNA Strand Scission from a C2'-Radical. J Org Chem 2016; 81:9199-9205. [PMID: 27668445 DOI: 10.1021/acs.joc.6b01760] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The C2'-carbon-hydrogen bond in ribonucleotides is significantly weaker than other carbohydrate carbon-hydrogen bonds in RNA or DNA. Independent generation of the C2'-uridine radical (1) in RNA oligonucleotides via Norrish type I photocleavage of a ketone-substituted nucleotide yields direct strand breaks via cleavage of the β-phosphate. The reactivity of 1 in different sequences and under a variety of conditions suggests that the rate constant for strand scission is significantly greater than 106 s-1 at pH 7.2. The initially formed C2'-radical (1) is not trapped under a variety of conditions, consistent with computational studies ( Chem.-Eur. J. 2009 , 15 , 2394 ) that suggest that the barrier to strand scission is very low and that synchronous proton transfer from the 2'-hydroxyl to the departing phosphate group facilitates cleavage. The C2'-radical could be a significant contributor to RNA strand scission by the hydroxyl radical, particularly under anaerobic conditions where 1 can be produced from nucleobase radicals.
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Affiliation(s)
- Rakesh Paul
- Department of Chemistry, Johns Hopkins University , 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Marc M Greenberg
- Department of Chemistry, Johns Hopkins University , 3400 North Charles Street, Baltimore, Maryland 21218, United States
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Lanier KA, Athavale SS, Petrov AS, Wartell R, Williams LD. Imprint of Ancient Evolution on rRNA Folding. Biochemistry 2016; 55:4603-13. [DOI: 10.1021/acs.biochem.6b00168] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Kathryn A. Lanier
- School of Chemistry and Biochemistry and ‡School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Shreyas S. Athavale
- School of Chemistry and Biochemistry and ‡School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Anton S. Petrov
- School of Chemistry and Biochemistry and ‡School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Roger Wartell
- School of Chemistry and Biochemistry and ‡School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Loren Dean Williams
- School of Chemistry and Biochemistry and ‡School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
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Kilburn D, Behrouzi R, Lee HT, Sarkar K, Briber RM, Woodson SA. Entropic stabilization of folded RNA in crowded solutions measured by SAXS. Nucleic Acids Res 2016; 44:9452-9461. [PMID: 27378777 PMCID: PMC5100557 DOI: 10.1093/nar/gkw597] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 06/21/2016] [Indexed: 01/29/2023] Open
Abstract
Non-coding RNAs must fold into specific structures that are stabilized by metal ions and other co-solutes in the cell's interior. Large crowder molecules such as PEG stabilize a bacterial group I ribozyme so that the RNA folds in low Mg2+ concentrations typical of the cell's interior. To understand the thermodynamic origins of stabilization by crowder molecules, small angle X-ray scattering was used to measure the folding and helix assembly of a bacterial group I ribozyme at different temperatures and in different MgCl2 and polyethylene glycol (PEG) concentrations. The resulting phase diagrams show that perturbations to folding by each variable do not overlap. A favorable enthalpy change drives the formation of compact, native-like structures, but requires Mg2+ ions at all temperatures studied (5–55°C). PEG reduces the entropic cost of helix assembly and increases correlations between RNA segments at all temperatures. The phase diagrams also revealed a semi-compact intermediate between the unfolded and folded ensemble that is locally more flexible than the unfolded state, as judged by SHAPE modification. These results suggest that environmental variables such as temperature and solute density will favor different types of RNA structures.
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Affiliation(s)
- Duncan Kilburn
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Reza Behrouzi
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Hui-Ting Lee
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Krishnarjun Sarkar
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Robert M Briber
- Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA
| | - Sarah A Woodson
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
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Espah Borujeni A, Salis HM. Translation Initiation is Controlled by RNA Folding Kinetics via a Ribosome Drafting Mechanism. J Am Chem Soc 2016; 138:7016-23. [PMID: 27199273 DOI: 10.1021/jacs.6b01453] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
RNA folding plays an important role in controlling protein synthesis as well as other cellular processes. Existing models have focused on how RNA folding energetics control translation initiation rate under equilibrium conditions but have largely ignored the effects of nonequilibrium RNA folding. We introduce a new mechanism, called "ribosome drafting", that explains how a mRNA's folding kinetics and the ribosome's binding rate collectively control its translation initiation rate. During cycles of translation, ribosome drafting emerges whenever successive ribosomes bind to a mRNA faster than the mRNA can refold, maintaining it in a nonequilibrium state with an acceleration of protein synthesis. Using computational design, time-correlated single photon counting, and expression measurements, we demonstrate that slow-folding and fast-folding RNA structures with equivalent folding energetics can vary protein synthesis rates by 1000-fold. We determine the necessary conditions for ribosome drafting by characterizing mRNAs with rationally designed ribosome binding rates, folding kinetics, and folding energetics, confirming the predictions of a nonequilibrium Markov model of translation. Our results have widespread implications, illustrating how competitive folding and assembly kinetics can shape the gene expression machinery's sequence-structure-function relationship inside cells.
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Affiliation(s)
- Amin Espah Borujeni
- Department of Chemical Engineering and ‡Department of Biological Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Howard M Salis
- Department of Chemical Engineering and ‡Department of Biological Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
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Draper DE. Folding of RNA tertiary structure: Linkages between backbone phosphates, ions, and water. Biopolymers 2016; 99:1105-13. [PMID: 23568785 DOI: 10.1002/bip.22249] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/14/2013] [Accepted: 03/25/2013] [Indexed: 01/08/2023]
Abstract
The functional forms of many RNAs have compact architectures. The placement of phosphates within such structures must be influenced not only by the strong electrostatic repulsion between phosphates, but also by networks of interactions between phosphates, water, and mobile ions. This review first explores what has been learned of the basic thermodynamic constraints on these arrangements from studies of hydration and ions in simple DNA molecules, and then gives an overview of what is known about ion and water interactions with RNA structures. A brief survey of RNA crystal structures identifies several interesting architectures in which closely spaced phosphates share hydration shells or phosphates are buried in environments that provide intramolecular hydrogen bonds or site-bound cations. Formation of these structures must require strong coupling between the uptake of ions and release of water.
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Affiliation(s)
- David E Draper
- Departments of Chemistry and Biophysics, Johns Hopkins University, Baltimore, MD, 21218
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36
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Crucial steps to life: From chemical reactions to code using agents. Biosystems 2016; 140:49-57. [DOI: 10.1016/j.biosystems.2015.12.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 12/05/2015] [Accepted: 12/07/2015] [Indexed: 01/21/2023]
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37
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Greenberg MM. Reactivity of Nucleic Acid Radicals. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2016; 50:119-202. [PMID: 28529390 DOI: 10.1016/bs.apoc.2016.02.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Nucleic acid oxidation plays a vital role in the etiology and treatment of diseases, as well as aging. Reagents that oxidize nucleic acids are also useful probes of the biopolymers' structure and folding. Radiation scientists have contributed greatly to our understanding of nucleic acid oxidation using a variety of techniques. During the past two decades organic chemists have applied the tools of synthetic and mechanistic chemistry to independently generate and study the reactive intermediates produced by ionizing radiation and other nucleic acid damaging agents. This approach has facilitated resolving mechanistic controversies and lead to the discovery of new reactive processes.
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Zhao C, Rajashankar KR, Marcia M, Pyle AM. Crystal structure of group II intron domain 1 reveals a template for RNA assembly. Nat Chem Biol 2015; 11:967-72. [PMID: 26502156 PMCID: PMC4651773 DOI: 10.1038/nchembio.1949] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 09/18/2015] [Indexed: 12/17/2022]
Abstract
Although the importance of large noncoding RNAs is increasingly appreciated, our understanding of their structures and architectural dynamics remains limited. In particular, we know little about RNA folding intermediates and how they facilitate the productive assembly of RNA tertiary structures. Here, we report the crystal structure of an obligate intermediate that is required during the earliest stages of group II intron folding. Composed of domain 1 from the Oceanobacillus iheyensis group II intron (266 nucleotides), this intermediate retains native-like features but adopts a compact conformation in which the active site cleft is closed. Transition between this closed and the open (native) conformation is achieved through discrete rotations of hinge motifs in two regions of the molecule. The open state is then stabilized by sequential docking of downstream intron domains, suggesting a 'first come, first folded' strategy that may represent a generalizable pathway for assembly of large RNA and ribonucleoprotein structures.
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Affiliation(s)
- Chen Zhao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Kanagalaghatta R. Rajashankar
- NE-CAT and Dept. of Chemistry and Chemical Biology, Cornell University Building 436E, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439
| | - Marco Marcia
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Anna Marie Pyle
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
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Mustoe AM, Al-Hashimi HM, Brooks CL. Secondary structure encodes a cooperative tertiary folding funnel in the Azoarcus ribozyme. Nucleic Acids Res 2015; 44:402-12. [PMID: 26481360 PMCID: PMC4705646 DOI: 10.1093/nar/gkv1055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 10/03/2015] [Indexed: 12/20/2022] Open
Abstract
A requirement for specific RNA folding is that the free-energy landscape discriminate against non-native folds. While tertiary interactions are critical for stabilizing the native fold, they are relatively non-specific, suggesting additional mechanisms contribute to tertiary folding specificity. In this study, we use coarse-grained molecular dynamics simulations to explore how secondary structure shapes the tertiary free-energy landscape of the Azoarcus ribozyme. We show that steric and connectivity constraints posed by secondary structure strongly limit the accessible conformational space of the ribozyme, and that these so-called topological constraints in turn pose strong free-energy penalties on forming different tertiary contacts. Notably, native A-minor and base-triple interactions form with low conformational free energy, while non-native tetraloop/tetraloop–receptor interactions are penalized by high conformational free energies. Topological constraints also give rise to strong cooperativity between distal tertiary interactions, quantitatively matching prior experimental measurements. The specificity of the folding landscape is further enhanced as tertiary contacts place additional constraints on the conformational space, progressively funneling the molecule to the native state. These results indicate that secondary structure assists the ribozyme in navigating the otherwise rugged tertiary folding landscape, and further emphasize topological constraints as a key force in RNA folding.
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Affiliation(s)
- Anthony M Mustoe
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Hashim M Al-Hashimi
- Department of Biochemistry and Chemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Charles L Brooks
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
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De Leonardis E, Lutz B, Ratz S, Cocco S, Monasson R, Schug A, Weigt M. Direct-Coupling Analysis of nucleotide coevolution facilitates RNA secondary and tertiary structure prediction. Nucleic Acids Res 2015; 43:10444-55. [PMID: 26420827 PMCID: PMC4666395 DOI: 10.1093/nar/gkv932] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 09/07/2015] [Indexed: 12/16/2022] Open
Abstract
Despite the biological importance of non-coding RNA, their structural characterization remains challenging. Making use of the rapidly growing sequence databases, we analyze nucleotide coevolution across homologous sequences via Direct-Coupling Analysis to detect nucleotide-nucleotide contacts. For a representative set of riboswitches, we show that the results of Direct-Coupling Analysis in combination with a generalized Nussinov algorithm systematically improve the results of RNA secondary structure prediction beyond traditional covariance approaches based on mutual information. Even more importantly, we show that the results of Direct-Coupling Analysis are enriched in tertiary structure contacts. By integrating these predictions into molecular modeling tools, systematically improved tertiary structure predictions can be obtained, as compared to using secondary structure information alone.
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Affiliation(s)
- Eleonora De Leonardis
- Computational and Quantitative Biology, Sorbonne Universités, Université Pierre et Marie Curie, UMR 7238, 75006 Paris, France Computational and Quantitative Biology, CNRS, UMR 7238, 75006 Paris, France Laboratoire de Physique Statistique de l'Ecole Normale Supérieure, associé au CNRS et à l'Université Pierre et Marie Curie, 75005 Paris, France
| | - Benjamin Lutz
- Steinbuch Centre for Computing, Karlsruher Institut für Technologie, 76133 Karlsruhe, Germany Fakultät für Physik, Karlsruher Institut für Technologie, 76133 Karlsruhe, Germany
| | - Sebastian Ratz
- Steinbuch Centre for Computing, Karlsruher Institut für Technologie, 76133 Karlsruhe, Germany Fakultät für Physik, Karlsruher Institut für Technologie, 76133 Karlsruhe, Germany
| | - Simona Cocco
- Laboratoire de Physique Statistique de l'Ecole Normale Supérieure, associé au CNRS et à l'Université Pierre et Marie Curie, 75005 Paris, France
| | - Rémi Monasson
- Laboratoire de Physique Théorique de l'Ecole Normale Supérieure, associé au CNRS et à l'Université Pierre et Marie Curie, 75005 Paris, France
| | - Alexander Schug
- Steinbuch Centre for Computing, Karlsruher Institut für Technologie, 76133 Karlsruhe, Germany
| | - Martin Weigt
- Computational and Quantitative Biology, Sorbonne Universités, Université Pierre et Marie Curie, UMR 7238, 75006 Paris, France Computational and Quantitative Biology, CNRS, UMR 7238, 75006 Paris, France
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Wostenberg C, Ceres P, Polaski JT, Batey RT. A Highly Coupled Network of Tertiary Interactions in the SAM-I Riboswitch and Their Role in Regulatory Tuning. J Mol Biol 2015; 427:3473-3490. [PMID: 26343759 DOI: 10.1016/j.jmb.2015.07.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 07/27/2015] [Accepted: 07/30/2015] [Indexed: 01/24/2023]
Abstract
RNA folding in vivo is significantly influenced by transcription, which is not necessarily recapitulated by Mg(2+)-induced folding of the corresponding full-length RNA in vitro. Riboswitches that regulate gene expression at the transcriptional level are an ideal system for investigating this aspect of RNA folding as ligand-dependent termination is obligatorily co-transcriptional, providing a clear readout of the folding outcome. The folding of representative members of the SAM-I family of riboswitches has been extensively analyzed using approaches focusing almost exclusively upon Mg(2+) and/or S-adenosylmethionine (SAM)-induced folding of full-length transcripts of the ligand binding domain. To relate these findings to co-transcriptional regulatory activity, we have investigated a set of structure-guided mutations of conserved tertiary architectural elements of the ligand binding domain using an in vitro single-turnover transcriptional termination assay, complemented with phylogenetic analysis and isothermal titration calorimetry data. This analysis revealed a conserved internal loop adjacent to the SAM binding site that significantly affects ligand binding and regulatory activity. Conversely, most single point mutations throughout key conserved features in peripheral tertiary architecture supporting the SAM binding pocket have relatively little impact on riboswitch activity. Instead, a secondary structural element in the peripheral subdomain appears to be the key determinant in observed differences in regulatory properties across the SAM-I family. These data reveal a highly coupled network of tertiary interactions that promote high-fidelity co-transcriptional folding of the riboswitch but are only indirectly linked to regulatory tuning.
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Affiliation(s)
- Christopher Wostenberg
- Department of Chemistry and Biochemistry, University of Colorado Boulder, 596 UCB, Boulder, CO 80309-0596, USA
| | - Pablo Ceres
- Department of Chemistry and Biochemistry, University of Colorado Boulder, 596 UCB, Boulder, CO 80309-0596, USA
| | - Jacob T Polaski
- Department of Chemistry and Biochemistry, University of Colorado Boulder, 596 UCB, Boulder, CO 80309-0596, USA
| | - Robert T Batey
- Department of Chemistry and Biochemistry, University of Colorado Boulder, 596 UCB, Boulder, CO 80309-0596, USA.
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How do metal ions direct ribozyme folding? Nat Chem 2015; 7:793-801. [PMID: 26391078 DOI: 10.1038/nchem.2330] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 07/20/2015] [Indexed: 02/07/2023]
Abstract
Ribozymes, which carry out phosphoryl-transfer reactions, often require Mg(2+) ions for catalytic activity. The correct folding of the active site and ribozyme tertiary structure is also regulated by metal ions in a manner that is not fully understood. Here we employ coarse-grained molecular simulations to show that individual structural elements of the group I ribozyme from the bacterium Azoarcus form spontaneously in the unfolded ribozyme even at very low Mg(2+) concentrations, and are transiently stabilized by the coordination of Mg(2+) ions to specific nucleotides. However, competition for scarce Mg(2+) and topological constraints that arise from chain connectivity prevent the complete folding of the ribozyme. A much higher Mg(2+) concentration is required for complete folding of the ribozyme and stabilization of the active site. When Mg(2+) is replaced by Ca(2+) the ribozyme folds, but the active site remains unstable. Our results suggest that group I ribozymes utilize the same interactions with specific metal ligands for both structural stability and chemical activity.
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Dutta D, Wedekind JE. Gene Regulation Gets in Tune: How Riboswitch Tertiary-Structure Networks Adapt to Meet the Needs of Their Transcription Units. J Mol Biol 2015; 427:3469-3472. [PMID: 26255959 DOI: 10.1016/j.jmb.2015.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Debapratim Dutta
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine and Dentistry, Rochester NY 14642, USA
| | - Joseph E Wedekind
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine and Dentistry, Rochester NY 14642, USA.
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When Competing Viruses Unify: Evolution, Conservation, and Plasticity of Genetic Identities. J Mol Evol 2015; 80:305-18. [PMID: 26014757 DOI: 10.1007/s00239-015-9683-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 05/12/2015] [Indexed: 02/06/2023]
Abstract
In the early 1970s, Manfred Eigen and colleagues developed the quasispecies model (qs) for the population-based origin of RNAs representing the early genetic code. The Eigen idea is basically that a halo of mutants is generated by error-prone replication around the master fittest type which will behave similarly as a biological population. But almost from the start, very interesting and unexpected observations were made regarding competition versus co-operation which suggested more complex interactions. It thus became increasingly clear that although viruses functioned similar to biological species, their behavior was much more complex than the original theory could explain, especially adaptation without changing the consensus involving minority populations. With respect to the origin of natural codes, meaning, and code-use in interactions (communication), it also became clear that individual fittest type-based mechanisms were likewise unable to explain the origin of natural codes such as the genetic code with their context- and consortia-dependence (pragmatic nature). This, instead, required the participation of groups of agents competent in the code and able to edit code because natural codes do not code themselves. Three lines of inquiry, experimental virology, quasispecies theory, and the study of natural codes converged to indicate that consortia of co-operative RNA agents such as viruses must be involved in the fitness of RNA and its involvement in communication, i.e., code-competent interactions. We called this co-operative form quasispecies consortia (qs-c). They are the essential agents that constitute the possibility of evolution of biological group identity. Finally, the basic interactional motifs for the emergence of group identity, communication, and co-operation-together with its opposing functions-are explained by the "Gangen" hypothesis.
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Tang Y, Bouvier E, Kwok CK, Ding Y, Nekrutenko A, Bevilacqua PC, Assmann SM. StructureFold: genome-wide RNA secondary structure mapping and reconstruction in vivo. Bioinformatics 2015; 31:2668-75. [PMID: 25886980 DOI: 10.1093/bioinformatics/btv213] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 04/12/2015] [Indexed: 01/06/2023] Open
Abstract
MOTIVATION RNAs fold into complex structures that are integral to the diverse mechanisms underlying RNA regulation of gene expression. Recent development of transcriptome-wide RNA structure profiling through the application of structure-probing enzymes or chemicals combined with high-throughput sequencing has opened a new field that greatly expands the amount of in vitro and in vivo RNA structural information available. The resultant datasets provide the opportunity to investigate RNA structural information on a global scale. However, the analysis of high-throughput RNA structure profiling data requires considerable computational effort and expertise. RESULTS We present a new platform, StructureFold, that provides an integrated computational solution designed specifically for large-scale RNA structure mapping and reconstruction across any transcriptome. StructureFold automates the processing and analysis of raw high-throughput RNA structure profiling data, allowing the seamless incorporation of wet-bench structural information from chemical probes and/or ribonucleases to restrain RNA secondary structure prediction via the RNAstructure and ViennaRNA package algorithms. StructureFold performs reads mapping and alignment, normalization and reactivity derivation, and RNA structure prediction in a single user-friendly web interface or via local installation. The variation in transcript abundance and length that prevails in living cells and consequently causes variation in the counts of structure-probing events between transcripts is accounted for. Accordingly, StructureFold is applicable to RNA structural profiling data obtained in vivo as well as to in vitro or in silico datasets. StructureFold is deployed via the Galaxy platform. AVAILABILITY AND IMPLEMENTATION StructureFold is freely available as a component of Galaxy available at: https://usegalaxy.org/. CONTACT yxt148@psu.edu or sma3@psu.edu SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Yin Tang
- Department of Biology, Center for RNA Molecular Biology, Bioinformatics and Genomics Graduate Program
| | - Emil Bouvier
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA 16802, USA, Galaxyproject.org, University Park, PA 16802, USA and Baltimore, MD 21218, USA
| | - Chun Kit Kwok
- Center for RNA Molecular Biology, Department of Chemistry and
| | - Yiliang Ding
- Department of Biology, Center for RNA Molecular Biology, Department of Chemistry and
| | - Anton Nekrutenko
- Bioinformatics and Genomics Graduate Program, Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA 16802, USA, Galaxyproject.org, University Park, PA 16802, USA and Baltimore, MD 21218, USA
| | - Philip C Bevilacqua
- Center for RNA Molecular Biology, Department of Chemistry and Plant Biology Graduate Program, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Sarah M Assmann
- Department of Biology, Center for RNA Molecular Biology, Bioinformatics and Genomics Graduate Program, Plant Biology Graduate Program, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Swadling JB, Wright DW, Suter JL, Coveney PV. Structure, dynamics, and function of the hammerhead ribozyme in bulk water and at a clay mineral surface from replica exchange molecular dynamics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2493-2501. [PMID: 25647546 DOI: 10.1021/la503685t] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Compared with proteins, the relationship between structure, dynamics, and function of RNA enzymes (known as ribozymes) is far less well understood, despite the fact that ribozymes are found in many organisms and are often conceived as "molecular fossils" of the first self-replicating molecules to have arisen on Earth. To investigate how ribozymal function is governed by structure and dynamics, we study the full hammerhead ribozyme in bulk water and in an aqueous clay mineral environment by computer simulation using replica-exchange molecular dynamics. Through extensive sampling of the major conformational states of the hammerhead ribozyme, we are able to show that the hammerhead manifests a free-energy landscape reminiscent of that which is well known in proteins, exhibiting a "funnel" topology that guides the ribozyme into its globally most stable conformation. The active-site geometry is found to be closely correlated to the tertiary structure of the ribozyme, thereby reconciling conflicts between previously proposed mechanisms for the self-scission of the hammerhead. The conformational analysis also accounts for the differences reported experimentally in the catalytic activity of the hammerhead ribozyme, which is reduced when interacting with clay minerals as compared with bulk water.
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Affiliation(s)
- Jacob B Swadling
- Centre for Computational Science, Department of Chemistry, University College London , 20 Gordon Street, London WC1H 0AJ, United Kingdom
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Chillón I, Marcia M, Legiewicz M, Liu F, Somarowthu S, Pyle AM. Native Purification and Analysis of Long RNAs. Methods Enzymol 2015; 558:3-37. [PMID: 26068736 PMCID: PMC4477701 DOI: 10.1016/bs.mie.2015.01.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The purification and analysis of long noncoding RNAs (lncRNAs) in vitro is a challenge, particularly if one wants to preserve elements of functional structure. Here, we describe a method for purifying lncRNAs that preserves the cotranscriptionally derived structure. The protocol avoids the misfolding that can occur during denaturation-renaturation protocols, thus facilitating the folding of long RNAs to a native-like state. This method is simple and does not require addition of tags to the RNA or the use of affinity columns. LncRNAs purified using this type of native purification protocol are amenable to biochemical and biophysical analysis. Here, we describe how to study lncRNA global compaction in the presence of divalent ions at equilibrium using sedimentation velocity analytical ultracentrifugation and analytical size-exclusion chromatography as well as how to use these uniform RNA species to determine robust lncRNA secondary structure maps by chemical probing techniques like selective 2'-hydroxyl acylation analyzed by primer extension and dimethyl sulfate probing.
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Affiliation(s)
- Isabel Chillón
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, USA; Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
| | - Marco Marcia
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, USA
| | - Michal Legiewicz
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, USA
| | - Fei Liu
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, USA
| | - Srinivas Somarowthu
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, USA
| | - Anna Marie Pyle
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, USA; Howard Hughes Medical Institute, Chevy Chase, Maryland, USA; Department of Chemistry, Yale University, New Haven, Connecticut, USA.
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Kirmizialtin S, Hennelly SP, Schug A, Onuchic JN, Sanbonmatsu KY. Integrating molecular dynamics simulations with chemical probing experiments using SHAPE-FIT. Methods Enzymol 2015; 553:215-34. [PMID: 25726467 DOI: 10.1016/bs.mie.2014.10.061] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Integration and calibration of molecular dynamics simulations with experimental data remain a challenging endeavor. We have developed a novel method to integrate chemical probing experiments with molecular simulations of RNA molecules by using a native structure-based model. Selective 2'-hydroxyl acylation by primer extension (SHAPE) characterizes the mobility of each residue in the RNA. Our method, SHAPE-FIT, automatically optimizes the potential parameters of the force field according to measured reactivities from SHAPE. The optimized parameter set allows simulations of dynamics highly consistent with SHAPE probing experiments. Such atomistic simulations, thoroughly grounded in experiment, can open a new window on RNA structure-function relations.
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Affiliation(s)
- Serdal Kirmizialtin
- New Mexico Consortium, Los Alamos, New Mexico, USA; Theoretical Biology and Biophysics, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA.
| | - Scott P Hennelly
- New Mexico Consortium, Los Alamos, New Mexico, USA; Theoretical Biology and Biophysics, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Alexander Schug
- Steinbuch Centre for Computing, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Jose N Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, Texas, USA; Department of Physics and Astronomy, Rice University, Houston, Texas, USA; Department of Chemistry, Rice University, Houston, Texas, USA; Department of Biosciences, Rice University, Houston, Texas, USA; Department of Biochemistry and Cell Biology, Rice University, Houston, Texas, USA
| | - Karissa Y Sanbonmatsu
- New Mexico Consortium, Los Alamos, New Mexico, USA; Theoretical Biology and Biophysics, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA.
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Gamalinda M, Woolford JL. Paradigms of ribosome synthesis: Lessons learned from ribosomal proteins. ACTA ACUST UNITED AC 2015; 3:e975018. [PMID: 26779413 DOI: 10.4161/21690731.2014.975018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Revised: 08/29/2014] [Accepted: 10/06/2014] [Indexed: 12/11/2022]
Abstract
The proteome in all cells is manufactured via the intricate process of translation by multimolecular factories called ribosomes. Nevertheless, these ribonucleoprotein particles, the largest of their kind, also have an elaborate assembly line of their own. Groundbreaking discoveries that bacterial ribosomal subunits can be self-assembled in vitro jumpstarted studies on how ribosomes are constructed. Until recently, ribosome assembly has been investigated almost entirely in vitro with bacterial small subunits under equilibrium conditions. In light of high-resolution ribosome structures and a more sophisticated toolkit, the past decade has been defined by a burst of kinetic studies in vitro and, importantly, also a shift to examining ribosome maturation in living cells, especially in eukaryotes. In this review, we summarize the principles governing ribosome assembly that emerged from studies focusing on ribosomal proteins and their interactions with rRNA. Understanding these paradigms has taken center stage, given the linkage between anomalous ribosome biogenesis and proliferative disorders.
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Affiliation(s)
- Michael Gamalinda
- Department of Biological Sciences; Carnegie Mellon University; Pittsburgh, PA USA; Present Address: Department of Epigenetics; Max Planck Institute of Immunobiology and Epigenetics; Freiburg, Germany
| | - John L Woolford
- Department of Biological Sciences; Carnegie Mellon University ; Pittsburgh, PA USA
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50
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Paul R, Greenberg MM. Rapid RNA strand scission following C2'-hydrogen atom abstraction. J Am Chem Soc 2015; 137:596-9. [PMID: 25580810 DOI: 10.1021/ja511401g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
C2'-Nucleotide radicals have been proposed as key intermediates in direct strand break formation in RNA exposed to ionizing radiation. Uridin-2'-yl radical (1) was independently generated in single- and double-stranded RNA via photolysis of a ketone precursor. Direct stand breaks result from heterolytic cleavage of the adjacent C3'-carbon-oxygen bond. Trapping of 1 by O2 or β-mercaptoethanol (1 M) does not compete with strand scission, indicating that phosphate elimination is >10(6) s(-1). Uracil loss also does not compete with strand scission. When considered in conjunction with reports that nucleobase radicals produce 1, this chemistry explains why RNA is significantly more susceptible to strand scission by ionizing radiation (hydroxyl radical) than is DNA.
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Affiliation(s)
- Rakesh Paul
- Department of Chemistry, Johns Hopkins University , 3400 North Charles Street, Baltimore, Maryland 21218, United States
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