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Chawla M, Kalra K, Cao Z, Cavallo L, Oliva R. Occurrence and stability of anion-π interactions between phosphate and nucleobases in functional RNA molecules. Nucleic Acids Res 2022; 50:11455-11469. [PMID: 36416268 PMCID: PMC9723503 DOI: 10.1093/nar/gkac1081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 10/19/2022] [Accepted: 10/26/2022] [Indexed: 11/24/2022] Open
Abstract
We present a systematic structural and energetic characterization of phosphate(OP)-nucleobase anion…π stacking interactions in RNAs. We observed OP-nucleobase stacking contacts in a variety of structural motifs other than regular helices and spanning broadly diverse sequence distances. Apart from the stacking between a phosphate and a guanine or a uracil two-residue upstream in specific U-turns, such interactions in RNA have been scarcely characterized to date. Our QM calculations showed an energy minimum at a distance between the OP atom and the nucleobase plane centroid slightly below 3 Å for all the nucleobases. By sliding the OP atom over the nucleobase plane we localized the optimal mutual positioning of the stacked moieties, corresponding to an energy minimum below -6 kcal•mol-1, for all the nucleobases, consistently with the projections of the OP atoms over the different π-rings we observed in experimental occurrences. We also found that the strength of the interaction clearly correlates with its electrostatic component, pointing to it as the most relevant contribution. Finally, as OP-uracil and OP-guanine interactions represent together 86% of the instances we detected, we also proved their stability under dynamic conditions in model systems simulated by state-of-the art DFT-MD calculations.
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Affiliation(s)
- Mohit Chawla
- Correspondence may also be addressed to Mohit Chawla. ;
| | - Kanav Kalra
- Department of Research and Innovation, STEMskills Research and Education Lab Private Limited, Faridabad 121002, Haryana, India
| | - Zhen Cao
- King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, Kaust Catalysis Center, Thuwal 23955-6900, Saudi Arabia
| | - Luigi Cavallo
- Correspondence may also be addressed to Luigi Cavallo. Tel: +966 02 8027566; Fax: +966 02 8021347;
| | - Romina Oliva
- To whom correspondence should be addressed. Tel: +39 081 5476541; Fax: +39 081 5476514;
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2
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Mukherjee D, Maiti S, Gouda PK, Sharma R, Roy P, Bhattacharyya D. RNABPDB: Molecular Modeling of RNA Structure-From Base Pair Analysis in Crystals to Structure Prediction. Interdiscip Sci 2022; 14:759-774. [PMID: 35705797 DOI: 10.1007/s12539-022-00528-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 05/05/2022] [Accepted: 05/17/2022] [Indexed: 06/15/2023]
Abstract
The stable three-dimensional structure of RNA is known to play several important biochemical roles, from post-transcriptional gene regulation to enzymatic action. These structures contain double-helical regions, which often have different types of non-canonical base pairs in addition to Watson-Crick base pairs. Hence, it is important to study their structures from experimentally obtained or even predicted ones, to understand their role, or to develop a drug against the potential targets. Molecular Modeling of RNA double helices containing non-canonical base pairs is a difficult process, particularly due to the unavailability of structural features of non-Watson-Crick base pairs. Here we show a composite web-server with an associated database that allows one to generate the structure of RNA double helix containing non-canonical base pairs using consensus parameters obtained from the database. The database classification is followed by an evaluation of the central tendency of the structural parameters as well as a quantitative estimation of interaction strengths. These parameters are used to construct three-dimensional structures of double helices composed of Watson-Crick and/or non-canonical base pairs. Our benchmark study to regenerate double-helical fragments of many experimentally derived RNA structures indicate very high accuracy. This composite server is expected to be highly useful in understanding functions of various pre-miRNA by modeling structures of the molecules and estimating binding efficiency. The database can be accessed from http://hdrnas.saha.ac.in/rnabpdb .
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Affiliation(s)
- Debasish Mukherjee
- Computational Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064, India.
- Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, 55128, Mainz, Germany.
| | - Satyabrata Maiti
- Computational Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064, India
- Homi Bhaba National Institute, Anushaktinagar, Mumbai, 400094, India
| | - Prasanta Kumar Gouda
- Computational Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064, India
| | - Richa Sharma
- Computational Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064, India
| | - Parthajit Roy
- Department of Computer Science, The University of Burdwan, Golapbag, Burdwan, 713104, India
| | - Dhananjay Bhattacharyya
- Computational Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064, India
- Homi Bhaba National Institute, Anushaktinagar, Mumbai, 400094, India
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3
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Stephen C, Mishanina TV. Alkaline pH has an unexpected effect on transcriptional pausing during synthesis of the E. coli pH-responsive riboswitch. J Biol Chem 2022; 298:102302. [PMID: 35934054 PMCID: PMC9472077 DOI: 10.1016/j.jbc.2022.102302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 07/13/2022] [Accepted: 07/16/2022] [Indexed: 11/17/2022] Open
Abstract
Riboswitches are 5′-untranslated regions of mRNA that change their conformation in response to ligand binding, allowing post-transcriptional gene regulation. This ligand-based model of riboswitch function has been expanded with the discovery of a “pH-responsive element” (PRE) riboswitch in Escherichia coli. At neutral pH, the PRE folds into a translationally inactive structure with an occluded ribosome-binding sequence, whereas at alkaline pH, the PRE adopts a translationally active structure. This unique riboswitch does not rely on ligand binding in a traditional sense to modulate its alternative folding outcomes. Rather, pH controls riboswitch folding by two possible modes that are yet to be distinguished; pH either regulates the transcription rate of RNA polymerase (RNAP) or acts on the RNA itself. Previous work suggested that RNAP pausing is prolonged by alkaline pH at two sites, stimulating PRE folding into the active structure. To date, there has been no rigorous exploration into how pH influences RNAP pausing kinetics during PRE synthesis. To provide that understanding and distinguish between pH acting on RNAP versus RNA, we investigated RNAP pausing kinetics at key sites for PRE folding under different pH conditions. We find that pH influences RNAP pausing but not in the manner proposed previously. Rather, alkaline pH either decreases or has no effect on RNAP pause longevity, suggesting that the modulation of RNAP pausing is not the sole mechanism by which pH affects PRE folding. These findings invite the possibility that the RNA itself actively participates in the sensing of pH.
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Lu N, Liang H, Miao C, Lan X, Qian P. Theoretical investigation of the mechanism of DMAP-promoted [4 + 2]-annulation of prop-2-ynylsulfonium with isatoic anhydride. CAN J CHEM 2022. [DOI: 10.1139/cjc-2021-0174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The mechanism for DMAP-promoted [4 + 2]-annulation of prop-2-ynylsulfonium with isatoic anhydride is investigated using the M06-2X functional. The reaction comprises isomerization of prop-2-ynylsulfonium in stage 1. Stage 2 includes DMAP-promoted deprotonation, nucleophilic addition, ring opening, and decarboxylation. Three steps of intramolecular cycloaddition, DMAP-promoted protonation, and dealkylation occur in stage 3, generating methylated DMAP and neutral thioether, which undergo double-bond isomerization to yield 3-methylthio-4-quinolone. The ability of DMAP to promote the reaction lies in the barrier decrease for alkyne isomerization, deprotonation/protonation of allenes, and dealkylation as effective bases for transferring protons and methyl groups. The roles of prop-2-ynylsulfonium and isatoic anhydride were demonstrated to be C2 and C4 synthons via Multiwfn analysis on the frontier molecular orbital. An alternative path was also confirmed by the Mayer bond order of the vital transition states.
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Affiliation(s)
- Nan Lu
- College of Chemistry and Material Science, Shandong Agricultural University, Taian City, Shandong Prov. 271018, P.R. China
- College of Chemistry and Material Science, Shandong Agricultural University, Taian City, Shandong Prov. 271018, P.R. China
| | - Hui Liang
- College of Chemistry and Material Science, Shandong Agricultural University, Taian City, Shandong Prov. 271018, P.R. China
- College of Chemistry and Material Science, Shandong Agricultural University, Taian City, Shandong Prov. 271018, P.R. China
| | - Chengxia Miao
- College of Chemistry and Material Science, Shandong Agricultural University, Taian City, Shandong Prov. 271018, P.R. China
- College of Chemistry and Material Science, Shandong Agricultural University, Taian City, Shandong Prov. 271018, P.R. China
| | - Xiaozheng Lan
- College of Chemistry and Material Science, Shandong Agricultural University, Taian City, Shandong Prov. 271018, P.R. China
- College of Chemistry and Material Science, Shandong Agricultural University, Taian City, Shandong Prov. 271018, P.R. China
| | - Ping Qian
- College of Chemistry and Material Science, Shandong Agricultural University, Taian City, Shandong Prov. 271018, P.R. China
- College of Chemistry and Material Science, Shandong Agricultural University, Taian City, Shandong Prov. 271018, P.R. China
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Hur JH, Kang CY, Lee S, Parveen N, Yu J, Shamim A, Yoo W, Ghosh A, Bae S, Park CJ, Kim KK. AC-motif: a DNA motif containing adenine and cytosine repeat plays a role in gene regulation. Nucleic Acids Res 2021; 49:10150-10165. [PMID: 34469538 PMCID: PMC8464069 DOI: 10.1093/nar/gkab728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 08/04/2021] [Accepted: 08/27/2021] [Indexed: 11/30/2022] Open
Abstract
I-motif or C4 is a four-stranded DNA structure with a protonated cytosine:cytosine base pair (C+:C) found in cytosine-rich sequences. We have found that oligodeoxynucleotides containing adenine and cytosine repeats form a stable secondary structure at a physiological pH with magnesium ion, which is similar to i-motif structure, and have named this structure ‘adenine:cytosine-motif (AC-motif)’. AC-motif contains C+:C base pairs intercalated with putative A+:C base pairs between protonated adenine and cytosine. By investigation of the AC-motif present in the CDKL3 promoter (AC-motifCDKL3), one of AC-motifs found in the genome, we confirmed that AC-motifCDKL3 has a key role in regulating CDKL3 gene expression in response to magnesium. This is further supported by confirming that genome-edited mutant cell lines, lacking the AC-motif formation, lost this regulation effect. Our results verify that adenine-cytosine repeats commonly present in the genome can form a stable non-canonical secondary structure with a non-Watson–Crick base pair and have regulatory roles in cells, which expand non-canonical DNA repertoires.
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Affiliation(s)
- Jeong Hwan Hur
- Department of Precision Medicine, Graduate Schoold of Basic Medical Science (GSBMS), Institute for Anti-microbial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
| | - Chan Young Kang
- Department of Chemistry, Hanyang University, Seoul 04763, Republic of Korea
| | - Sungjin Lee
- Department of Chemistry, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Nazia Parveen
- Department of Precision Medicine, Graduate Schoold of Basic Medical Science (GSBMS), Institute for Anti-microbial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
| | - Jihyeon Yu
- Department of Chemistry, Hanyang University, Seoul 04763, Republic of Korea
| | - Amen Shamim
- Department of Precision Medicine, Graduate Schoold of Basic Medical Science (GSBMS), Institute for Anti-microbial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea.,Centre of Agricultural Biochemistry and Biotechnology, University of Agriculture, Faisalabad 38040, Pakistan
| | - Wanki Yoo
- Department of Precision Medicine, Graduate Schoold of Basic Medical Science (GSBMS), Institute for Anti-microbial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
| | - Ambarnil Ghosh
- Department of Precision Medicine, Graduate Schoold of Basic Medical Science (GSBMS), Institute for Anti-microbial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
| | - Sangsu Bae
- Department of Chemistry, Hanyang University, Seoul 04763, Republic of Korea
| | - Chin-Ju Park
- Department of Chemistry, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Kyeong Kyu Kim
- Department of Precision Medicine, Graduate Schoold of Basic Medical Science (GSBMS), Institute for Anti-microbial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea.,Samsung Biomedical Research Institute, Samsung Advanced Institute for Health Sciences and Technology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
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6
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Halder A, Kumar S, Valsson O, Reddy G. Mg 2+ Sensing by an RNA Fragment: Role of Mg 2+-Coordinated Water Molecules. J Chem Theory Comput 2020; 16:6702-6715. [PMID: 32941038 DOI: 10.1021/acs.jctc.0c00589] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
RNA molecules selectively bind to specific metal ions to populate their functional active states, making it important to understand their source of ion selectivity. In large RNA systems, metal ions interact with the RNA at multiple locations, making it difficult to decipher the precise role of ions in folding. To overcome this complexity, we studied the role of different metal ions (Mg2+, Ca2+, and K+) in the folding of a small RNA hairpin motif (5'-ucCAAAga-3') using unbiased all-atom molecular dynamics simulations. The advantage of studying this system is that it requires specific binding of a single metal ion to fold to its native state. We find that even for this small RNA, the folding free energy surface (FES) is multidimensional as different metal ions present in the solution can simultaneously facilitate folding. The FES shows that specific binding of a metal ion is indispensable for its folding. We further show that in addition to the negatively charged phosphate groups, the spatial organization of electronegative nucleobase atoms drives the site-specific binding of the metal ions. Even though the binding site cannot discriminate between different metal ions, RNA folds efficiently only in a Mg2+ solution. We show that the rigid network of Mg2+-coordinated water molecules facilitates the formation of important interactions in the transition state. The other metal ions such as K+ and Ca2+ cannot facilitate the formation of such interactions. These results allow us to hypothesize possible metal-sensing mechanisms in large metalloriboswitches and also provide useful insights into the design of appropriate collective variables for studying large RNA molecules using enhanced sampling methods.
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Affiliation(s)
- Antarip Halder
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru 560012, Karnataka, India
| | - Sunil Kumar
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru 560012, Karnataka, India
| | - Omar Valsson
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Govardhan Reddy
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru 560012, Karnataka, India
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7
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Cabaj MK, Dominiak PM. Frequency and hydrogen bonding of nucleobase homopairs in small molecule crystals. Nucleic Acids Res 2020; 48:8302-8319. [PMID: 32725210 PMCID: PMC7470937 DOI: 10.1093/nar/gkaa629] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 07/10/2020] [Accepted: 07/16/2020] [Indexed: 11/16/2022] Open
Abstract
We used the high resolution and accuracy of the Cambridge Structural Database (CSD) to provide detailed information regarding base pairing interactions of selected nucleobases. We searched for base pairs in which nucleobases interact with each other through two or more hydrogen bonds and form more or less planar structures. The investigated compounds were either free forms or derivatives of adenine, guanine, hypoxanthine, thymine, uracil and cytosine. We divided our findings into categories including types of pairs, protonation patterns and whether they are formed by free bases or substituted ones. We found base pair types that are exclusive to small molecule crystal structures, some that can be found only in RNA containing crystal structures and many that are native to both environments. With a few exceptions, nucleobase protonation generally followed a standard pattern governed by pKa values. The lengths of hydrogen bonds did not depend on whether the nucleobases forming a base pair were charged or not. The reasons why particular nucleobases formed base pairs in a certain way varied significantly.
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Affiliation(s)
- Małgorzata Katarzyna Cabaj
- Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, ul. Żwirki i Wigury 101, 02-089 Warszawa, Poland
| | - Paulina Maria Dominiak
- Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, ul. Żwirki i Wigury 101, 02-089 Warszawa, Poland
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Cheng R, Loire E, Martens J, Fridgen TD. An IRMPD spectroscopic and computational study of protonated guanine-containing mismatched base pairs in the gas phase. Phys Chem Chem Phys 2020; 22:2999-3007. [DOI: 10.1039/c9cp06393e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Infrared multiple photon dissociation spectroscopy has been used to probe the structures of the three protonated base-pair mismatches containing 9-ethylguanine (9eG) in the gas phase. Some of these protonated base-pairs have been identified in RNA.
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Affiliation(s)
- Ruodi Cheng
- Department of Chemistry
- Memorial University
- St. John's
- Canada
| | - Estelle Loire
- Laboratoire Chimie Physique – CLIO
- Campus Universite d’Orsay
- France
| | - Jonathan Martens
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- Nijmegen
- The Netherlands
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Maganti L, Bhattacharyya D. Sequence specificity in DNA–drug intercalation: MD simulation and density functional theory approaches. J Comput Aided Mol Des 2019; 34:83-95. [DOI: 10.1007/s10822-019-00268-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 11/29/2019] [Indexed: 12/14/2022]
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10
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Fuchs E, Falschlunger C, Micura R, Breuker K. The effect of adenine protonation on RNA phosphodiester backbone bond cleavage elucidated by deaza-nucleobase modifications and mass spectrometry. Nucleic Acids Res 2019; 47:7223-7234. [PMID: 31276590 PMCID: PMC6698743 DOI: 10.1093/nar/gkz574] [Citation(s) in RCA: 12] [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: 03/26/2019] [Revised: 06/15/2019] [Accepted: 06/21/2019] [Indexed: 12/14/2022] Open
Abstract
The catalytic strategies of small self-cleaving ribozymes often involve interactions between nucleobases and the ribonucleic acid (RNA) backbone. Here we show that multiply protonated, gaseous RNA has an intrinsic preference for the formation of ionic hydrogen bonds between adenine protonated at N3 and the phosphodiester backbone moiety on its 5'-side that facilitates preferential phosphodiester backbone bond cleavage upon vibrational excitation by low-energy collisionally activated dissociation. Removal of the basic N3 site by deaza-modification of adenine was found to abrogate preferential phosphodiester backbone bond cleavage. No such effects were observed for N1 or N7 of adenine. Importantly, we found that the pH of the solution used for generation of the multiply protonated, gaseous RNA ions by electrospray ionization affects phosphodiester backbone bond cleavage next to adenine, which implies that the protonation patterns in solution are at least in part preserved during and after transfer into the gas phase. Our study suggests that interactions between protonated adenine and phosphodiester moieties of RNA may play a more important mechanistic role in biological processes than considered until now.
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Affiliation(s)
- Elisabeth Fuchs
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Christoph Falschlunger
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Kathrin Breuker
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
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11
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Porter JE, Chapagain P, Fernandez-Lima F. Single-stranded DNA structural diversity: TAGGGT from monomers to dimers to tetramer formation. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33 Suppl 2:60-65. [PMID: 30506977 DOI: 10.1002/rcm.8367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 11/27/2018] [Accepted: 11/27/2018] [Indexed: 06/09/2023]
Abstract
RATIONALE DNA quadruplex structures have emerged as novel drug targets due to their role in preventing abnormal gene transcription and maintaining telomere stability. Trapped Ion Mobility Spectrometry-Mass Spectrometry (TIMS-MS), combined with theoretical modeling, is a powerful tool for studying the kinetic intermediates of DNA complexes formed in solution and interrogated in the gas phase after desolvation. METHODS A TAGGGT ssDNA sequence was purchased and studied in 10 mM ammonium acetate using nanospray electrospray ionization (nESI)-TIMS-MS in positive and negative ion mode. Collisional cross section (CCS) profiles were measured using internal calibration (Tune Mix). Theoretical structures were proposed based on molecular dynamics, charge location and geometry optimization for the most intense IMS bands based on the number of TAGGGT units, adduct form and charge states. RESULTS A distribution of monomeric, dimeric and tetrameric TAGGGT structures were formed in solution and separated in the gas phase based on their mobility and m/z value (e.g., [M + 2H]+2 , [2M + 3H]+3 , [M - 2H]-2 , [2M - 3H]-3 , [4M + 4H]+4 , [4M + 3H + NH4 ]+4 , [4M + 2H + 2NH4 ]+4 and [4M + H + 3NH4 ]+4 ). The high mobility resolution of the TIMS-MS analyzer permitted the observation of multiple CCS bands per molecular ion form. Comparison with theoretical candidate structures suggests that monomeric TAGGGT species are stabilized by A-T and G+ -G interactions, with the size of the conformer influenced by the proton location. In the case of the TAGGGT quadruplex, the protonated species displayed a broad CCS distribution, while six discrete conformers were stabilized by the presence of ammonium ions (n = 1-3). CONCLUSIONS This is the first observation of multiple conformations of TAGGGT complexes (n = 1, 2 and 4) in 10 mM ammonium acetate. Candidate structures with intramolecular interactions of the form of G+ -G and traditional A-T base pairing agreed with the experimental trends. Our results demonstrate the structural diversity of TAGGGT monomers, dimers and tetramers in the gas phase beyond the previously reported solution structure, using 10 mM ammonium acetate to replicate biological conditions.
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Affiliation(s)
- Jacob E Porter
- Department of Chemistry & Biochemistry, Florida International University, Miami, FL, USA
| | - Prem Chapagain
- Department of Physics, Florida International University, Miami, FL, USA
- Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Francisco Fernandez-Lima
- Department of Chemistry & Biochemistry, Florida International University, Miami, FL, USA
- Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
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12
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Park JJ, Han SY. Alternated Branching Ratios by Anomaly in Collision-Induced Dissociation of Proton-Bound Hoogsteen Base Pairs of 1-Methylcytosine with 1-Methylguanine and 9-Methylguanine. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:846-854. [PMID: 30911905 DOI: 10.1007/s13361-019-02161-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 01/26/2019] [Accepted: 02/14/2019] [Indexed: 06/09/2023]
Abstract
A comparative study on the proton-bound complexes of 1-methylcytosine (1-mC) with 1-methylguanine (1-mG) and 9-methylguanine (9-mG), [1-mC:1-mG:H]+ and [1-mC:9-mG:H]+, respectively, was carried out using energy-resolved collision-induced dissociation (ER-CID) experiments in combination with quantum chemical calculations. In ER-CID experiments, the measured survival yields indicated an essentially identical stability for the two proton-bound complexes. In comparison with the lowest-energy structures and base-pairing energetics predicted at the B3LYP/6-311+G(2d,2p) theory level, both complexes produced in this study were suggested to be proton-bound Hoogsteen base pairs. Curiously, despite the similarity in structures, binding energetics, and potential energy surfaces predicted by the B3LYP theory, the fragment branching ratios exhibited an intriguing alternation between the two proton-bound Hoogsteen base pairs. The CID of [1-mC:1-mG:H]+ produced protonated cytosines, [1-mC:H]+, more abundantly than [1-mG:H]+, whereas that of [1-mC:9-mG:H]+ gave rise to a more pronounced production of protonated guanines, [9-mG:H]+. However, using the proton affinities of moieties predicted by the high-accuracy methods, including CBS-QB3 and the Guassian-4 theory, the anomaly known for [Cytosine:Guanine:H]+ (J. Am. Soc. Mass Spectrom. 29, 2368-2379 (2018)) successfully accounted for the alternated branching ratios. Thereby, the anomaly, more specifically, the production of proton-transferred fragments of O-protonated cytosines in the CID of proton-bound Hoogsteen base pairs, is indeed real, which is disclosed as the alternated branching ratios in the CID spectra of [1-mC:1-mG:H]+ and [1-mC:9-mG:H]+ in this study. Graphical Abstract .
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Affiliation(s)
- Jeong Ju Park
- Department of Nanochemistry, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea
| | - Sang Yun Han
- Department of Nanochemistry, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea.
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13
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Bhattacharya S, Jhunjhunwala A, Halder A, Bhattacharyya D, Mitra A. Going beyond base-pairs: topology-based characterization of base-multiplets in RNA. RNA (NEW YORK, N.Y.) 2019; 25:573-589. [PMID: 30792229 PMCID: PMC6467009 DOI: 10.1261/rna.068551.118] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 02/18/2019] [Indexed: 05/17/2023]
Abstract
Identification and characterization of base-multiplets, which are essentially mediated by base-pairing interactions, can provide insights into the diversity in the structure and dynamics of complex functional RNAs, and thus facilitate hypothesis driven biological research. The necessary nomenclature scheme, an extension of the geometric classification scheme for base-pairs by Leontis and Westhof, is however available only for base-triplets. In the absence of information on topology, this scheme is not applicable to quartets and higher order multiplets. Here we propose a topology-based classification scheme which, in conjunction with a graph-based algorithm, can be used for the automated identification and characterization of higher order base-multiplets in RNA structures. Here, the RNA structure is represented as a graph, where nodes represent nucleotides and edges represent base-pairing connectivity. Sets of connected components (of n nodes) within these graphs constitute subgraphs representing multiplets of "n" nucleotides. The different topological variants of the RNA multiplets thus correspond to different nonisomorphic forms of these subgraphs. To annotate RNA base-multiplets unambiguously, we propose a set of topology-based nomenclature rules for quartets, which are extendable to higher multiplets. We also demonstrate the utility of our approach toward the identification and annotation of higher order RNA multiplets, by investigating the occurrence contexts of selected examples in order to gain insights regarding their probable functional roles.
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Affiliation(s)
- Sohini Bhattacharya
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, India
| | - Ayush Jhunjhunwala
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, India
| | - Antarip Halder
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, India
| | - Dhananjay Bhattacharyya
- Computational Science Division, Saha Institute of Nuclear Physics (SINP), 1/AF, Bidhannagar, Kolkata 700064, India
| | - Abhijit Mitra
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, India
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14
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Halder A, Data D, Seelam PP, Bhattacharyya D, Mitra A. Estimating Strengths of Individual Hydrogen Bonds in RNA Base Pairs: Toward a Consensus between Different Computational Approaches. ACS OMEGA 2019; 4:7354-7368. [PMID: 31459834 PMCID: PMC6648064 DOI: 10.1021/acsomega.8b03689] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 04/12/2019] [Indexed: 06/10/2023]
Abstract
Noncoding RNA molecules are composed of a large variety of noncanonical base pairs that shape up their functionally competent folded structures. Each base pair is composed of at least two interbase hydrogen bonds (H-bonds). It is expected that the characteristic geometry and stability of different noncanonical base pairs are determined collectively by the properties of these interbase H-bonds. We have studied the ground-state electronic properties [using density functional theory (DFT) and DFT-D3-based methods] of all the 118 normal base pairs and 36 modified base pairs, belonging to 12 different geometric families (cis and trans of WW, WH, HH, WS, HS, and SS) that occur in a nonredundant set of high-resolution RNA crystal structures. Having addressed some of the limitations of the earlier approaches, we provide here a comprehensive compilation of the average energies of different types of interbase H-bonds (E HB). We have also characterized each interbase H-bond using 13 different parameters that describe its geometry, charge distribution at its bond critical point (BCP), and n → σ*-type charge transfer from filled π orbitals of the H-bond acceptor to the empty antibonding orbital of the H-bond donor. On the basis of the extent of their linear correlation with the H-bonding energy, we have shortlisted five parameters to model linear equations for predicting E HB values. They are (i) electron density at the BCP: ρ, (ii) its Laplacian: ∇2ρ, (iii) stabilization energy due to n → σ*-type charge transfer: E(2), (iv) donor-hydrogen distance, and (v) hydrogen-acceptor distance. We have performed single variable and multivariable linear regression analysis over the normal base pairs and have modeled sets of linear relationships between these five parameters and E HB. Performance testing of our model over the set of modified base pairs shows promising results, at least for the moderately strong H-bonds.
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Affiliation(s)
- Antarip Halder
- Center
for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology
(IIIT-H), Gachibowli, Hyderabad 500032, India
| | - Dhruv Data
- Center
for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology
(IIIT-H), Gachibowli, Hyderabad 500032, India
| | - Preethi P. Seelam
- Center
for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology
(IIIT-H), Gachibowli, Hyderabad 500032, India
| | - Dhananjay Bhattacharyya
- Computational
Science Division, Saha Institute of Nuclear
Physics(SINP), 1/AF,
Bidhannagar, Kolkata 700064, India
| | - Abhijit Mitra
- Center
for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology
(IIIT-H), Gachibowli, Hyderabad 500032, India
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15
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Halder A, Vemuri S, Roy R, Katuri J, Bhattacharyya D, Mitra A. Evidence for Hidden Involvement of N3-Protonated Guanine in RNA Structure and Function. ACS OMEGA 2019; 4:699-709. [PMID: 30775644 PMCID: PMC6372247 DOI: 10.1021/acsomega.8b02908] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 12/25/2018] [Indexed: 05/05/2023]
Abstract
Charged nucleobases have been found to occur in several known RNA molecules and are considered essential for their structure and function. The mechanism of their involvement is however not yet fully understood. Revelation of the role of N7-protonated guanine, in modulating the geometry and stability of noncanonical base pairs formed through its unprotonated edges [Watson-Crick (WC) and sugar], has triggered the need to evaluate the feasibility of similar roles of other protonated nucleobases [Halder et al., Phys Chem Chem Phys, 2015, 17, 26249]. In this context, N3 protonation of guanine makes an interesting case as its influence on the charge distribution of the WC edge is similar to that of N7 protonation, though its thermodynamic cost of protonation is significantly higher. In this work, we have carried out structural bioinformatics analyses and quantum mechanics-based calculations to show that N3 protonation of guanine may take place in a cellular environment, at least in the G:C W:W Trans and G:G W:H Cis base pairs. Our results provide a reasonable starting point for future investigations in order to address the larger mechanistic question.
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Affiliation(s)
- Antarip Halder
- Center
for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology,
Hyderabad (IIIT-H), Gachibowli, Hyderabad 500032, Telangana, India
| | - Saurabh Vemuri
- Center
for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology,
Hyderabad (IIIT-H), Gachibowli, Hyderabad 500032, Telangana, India
| | - Rohit Roy
- Center
for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology,
Hyderabad (IIIT-H), Gachibowli, Hyderabad 500032, Telangana, India
| | - Jayanth Katuri
- Center
for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology,
Hyderabad (IIIT-H), Gachibowli, Hyderabad 500032, Telangana, India
| | - Dhananjay Bhattacharyya
- Computational
Science Division, Saha Institute of Nuclear
Physics (SINP), 1/AF,
Bidhannagar, Kolkata 700064, India
| | - Abhijit Mitra
- Center
for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology,
Hyderabad (IIIT-H), Gachibowli, Hyderabad 500032, Telangana, India
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16
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Pandeti S, Feketeová L, Reddy TJ, Abdoul-Carime H, Farizon B, Farizon M, Märk TD. Binding preference of nitroimidazolic radiosensitizers to nucleobases and nucleosides probed by electrospray ionization mass spectrometry and density functional theory. J Chem Phys 2019; 150:014302. [PMID: 30621427 DOI: 10.1063/1.5062604] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Nitroimidazolic radiosensitizers are used in radiation therapy to selectively sensitize cancer cells deprived of oxygen, and the actual mechanism of radiosensitization is still not understood. Selecting five radiosensitizers (1-methyl-5-nitroimidazole, ronidazole, ornidazole, metronidazole, and nimorazole) with a common 5-nitroimidazolic ring with different substitutions at N1 and C2 positions of the imidazole moiety, we investigate here their binding to nucleobases (A, T, G, and C) and nucleosides (As, Td, Gs, and Cd) via the positive electrospray ionization mass spectrometry experiments. In addition, quantum chemical calculations at the M062x/6-311+G(d,p) level of theory and basis set were used to determine binding energies of the proton bound dimers of a radiosensitizer and a nucleobase. The positive electrospray ionization leads to the formation of proton bound dimers of all radiosensitizers except 1-methyl-5-nitroimidazole in high abundance with C and smaller abundance with G. Ronidazole and metronidazole formed less abundant dimers also with A, while no dimers were observed to be formed at all with T. In contrast to the case of the nucleoside Td, the dimer intensity is as high as that with Cd, while the abundance of the dimer with Gs is smaller than that of the former. The experimental results are consistent with the calculations of binding energies suggesting proton bound dimers with C and G to be the strongest bound ones. Finally, a barrier-free proton transfer is observed when protonated G or C approaches the nitroimidazole ring.
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Affiliation(s)
- S Pandeti
- Université de Lyon, Université Claude Bernard Lyon1, Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, 69622 Villeurbanne Cedex, France
| | - L Feketeová
- Université de Lyon, Université Claude Bernard Lyon1, Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, 69622 Villeurbanne Cedex, France
| | - T J Reddy
- Analytical Chemistry and Mass Spectrometry Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - H Abdoul-Carime
- Université de Lyon, Université Claude Bernard Lyon1, Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, 69622 Villeurbanne Cedex, France
| | - B Farizon
- Université de Lyon, Université Claude Bernard Lyon1, Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, 69622 Villeurbanne Cedex, France
| | - M Farizon
- Université de Lyon, Université Claude Bernard Lyon1, Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, 69622 Villeurbanne Cedex, France
| | - T D Märk
- Institut für Ionenphysik und Angewandte Physik, Leopold Franzens Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
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17
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Park JJ, Lee CS, Han SY. Proton Transfer Accounting for Anomalous Collision-Induced Dissociation of Proton-Bound Hoogsteen Base Pair of Cytosine and Guanine. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:2368-2379. [PMID: 30215166 DOI: 10.1007/s13361-018-2060-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/08/2018] [Accepted: 08/08/2018] [Indexed: 06/08/2023]
Abstract
To understand the anomalous collision-induced dissociation (CID) behavior of the proton-bound Hoogsteen base pair of cytosine (C) and guanine (G), C:H+∙∙∙G, we investigated CID of a homologue series of proton-bound heterodimers of C, 1-methylcytosine, and 5-methylcytosine with G as a common base partner. The CID experiments were performed in an energy-resolved way (ER-CID) under both multiple and near-single collision conditions. The relative stabilities of the protonated complexes examined by ER-CID suggested that the proton-bound complexes produced by electrospray ionization in this study are proton-bound Hoogsteen base pairs. On the other hand, in contrast to the other base pairs, CID of C:H+∙∙∙G exhibited more abundant productions of C:H+, the fragment protonated on the moiety with a smaller proton affinity, than that of G:H+. This appeared to contradict general prediction based on the kinetic method. However, further theoretical exploration of potential energy surfaces found that there can be facile proton transfers in the proton-bound Hoogsteen base pairs during the CID process, which makes the process accessible to an additional product state of O-protonated C for C:H+ fragments. The presence of an additional dissociation channel, which in other words corresponds to twofold degeneracy in the transition state leading to C:H+ fragments, effectively doubles the apparent reaction rate for production of C:H+. In this way, the process gives rise to the anomaly, the observed pronounced formation of C:H+ in the CID of the proton-bound Hoogsteen base pair, C:H+∙∙∙G. Graphical Abstract ᅟ.
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Affiliation(s)
- Jeong Ju Park
- Department of Nanochemistry, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea
| | - Choong Sik Lee
- Scientific Investigation Laboratory, Ministry of National Defense, 22 Itaewon-ro, Yongsan-gu, Seoul, 04383, Republic of Korea
| | - Sang Yun Han
- Department of Nanochemistry, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea.
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18
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Kumar P, Cabaj MK, Pazio A, Dominiak PM. Protonated nucleobases are not fully ionized in their chloride salt crystals and form metastable base pairs further stabilized by the surrounding anions. IUCRJ 2018; 5:449-469. [PMID: 30002846 PMCID: PMC6038959 DOI: 10.1107/s2052252518006346] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 04/25/2018] [Indexed: 06/08/2023]
Abstract
This paper presents experimental charge-density studies of cytosinium chloride, adeninium chloride hemihydrate and guaninium dichloride crystals based on ultra-high-resolution X-ray diffraction data and extensive theoretical calculations. The results confirm that the cohesive energies of the studied systems are dominated by contributions from intermolecular electrostatic interactions, as expected for ionic crystals. Electrostatic interaction energies (Ees) usually constitute 95% of the total interaction energy. The Ees energies in this study were several times larger in absolute value when compared, for example, with dimers of neutral nucleobases. However, they were not as large as some theoretical calculations have predicted. This was because the molecules appeared not to be fully ionized in the studied crystals. Apart from charge transfer from chlorine to the protonated nucleobases, small but visible charge redistribution within the nucleobase cations was observed. Some dimers of singly protonated bases in the studied crystals, namely a cytosinium-cytosinium trans sugar/sugar edge pair and an adeninium-adeninium trans Hoogsteen/Hoogsteen edge pair, exhibited attractive interactions (negative values of Ees) or unusually low repulsion despite identical molecular charges. The pairs are metastable as a result of strong hydrogen bonding between bases which overcompensates the overall cation-cation repulsion, the latter being weakened due to charge transfer and molecular charge-density polarization.
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Affiliation(s)
- Prashant Kumar
- Biological and Chemical Research Center, Department of Chemistry, University of Warsaw, ul. Żwirki i Wigury 101, Warszawa 02-089, Poland
| | - Malgorzata Katarzyna Cabaj
- Biological and Chemical Research Center, Department of Chemistry, University of Warsaw, ul. Żwirki i Wigury 101, Warszawa 02-089, Poland
| | - Aleksandra Pazio
- Biological and Chemical Research Center, Department of Chemistry, University of Warsaw, ul. Żwirki i Wigury 101, Warszawa 02-089, Poland
| | - Paulina Maria Dominiak
- Biological and Chemical Research Center, Department of Chemistry, University of Warsaw, ul. Żwirki i Wigury 101, Warszawa 02-089, Poland
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19
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Halder A, Roy R, Bhattacharyya D, Mitra A. Consequences of Mg2+ binding on the geometry and stability of RNA base pairs. Phys Chem Chem Phys 2018; 20:21934-21948. [DOI: 10.1039/c8cp03602k] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Quantum chemical calculations reveal the role of magnesium in stabilizing the geometries of intrinsically unstable RNA base pairs.
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Affiliation(s)
- Antarip Halder
- Center for Computational Natural Sciences and Bioinformatics (CCNSB)
- International Institute of Information Technology (IIIT-H)
- Hyderabad 500032
- India
| | - Rohit Roy
- Center for Computational Natural Sciences and Bioinformatics (CCNSB)
- International Institute of Information Technology (IIIT-H)
- Hyderabad 500032
- India
| | | | - Abhijit Mitra
- Center for Computational Natural Sciences and Bioinformatics (CCNSB)
- International Institute of Information Technology (IIIT-H)
- Hyderabad 500032
- India
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20
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Chawla M, Chermak E, Zhang Q, Bujnicki JM, Oliva R, Cavallo L. Occurrence and stability of lone pair-π stacking interactions between ribose and nucleobases in functional RNAs. Nucleic Acids Res 2017; 45:11019-11032. [PMID: 28977572 PMCID: PMC5737201 DOI: 10.1093/nar/gkx757] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Accepted: 08/17/2017] [Indexed: 12/13/2022] Open
Abstract
The specific folding pattern and function of RNA molecules lies in various weak interactions, in addition to the strong base-base pairing and stacking. One of these relatively weak interactions, characterized by the stacking of the O4' atom of a ribose on top of the heterocycle ring of a nucleobase, has been known to occur but has largely been ignored in the description of RNA structures. We identified 2015 ribose-base stacking interactions in a high-resolution set of non-redundant RNA crystal structures. They are widespread in structured RNA molecules and are located in structural motifs other than regular stems. Over 50% of them involve an adenine, as we found ribose-adenine contacts to be recurring elements in A-minor motifs. Fewer than 50% of the interactions involve a ribose and a base of neighboring residues, while approximately 30% of them involve a ribose and a nucleobase at least four residues apart. Some of them establish inter-domain or inter-molecular contacts and often implicate functionally relevant nucleotides. In vacuo ribose-nucleobase stacking interaction energies were calculated by quantum mechanics methods. Finally, we found that lone pair-π stacking interactions also occur between ribose and aromatic amino acids in RNA-protein complexes.
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Affiliation(s)
- Mohit Chawla
- King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia.,Kaust Catalysis Center, Thuwal 23955-6900, Saudi Arabia
| | - Edrisse Chermak
- King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia.,Kaust Catalysis Center, Thuwal 23955-6900, Saudi Arabia
| | - Qingyun Zhang
- King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Janusz M Bujnicki
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, ul. Ks. Trojdena 4, 02-109 Warsaw, Poland.,Laboratory of Bioinformatics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Romina Oliva
- Department of Sciences and Technologies, University Parthenope of Naples, Centro Direzionale Isola C4, I-80143 Naples, Italy.,King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, Thuwal 23955-6900, Saudi Arabia
| | - Luigi Cavallo
- King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia.,Kaust Catalysis Center, Thuwal 23955-6900, Saudi Arabia
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21
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Jun J, Han SY. Theoretical exploration of gas-phase conformers of proton-bound non-covalent heterodimers of guanine and cytosine rare tautomers: structures and energies. Theor Chem Acc 2017. [DOI: 10.1007/s00214-017-2165-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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22
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Barroso da Silva FL, Derreumaux P, Pasquali S. Fast coarse-grained model for RNA titration. J Chem Phys 2017; 146:035101. [PMID: 28109220 DOI: 10.1063/1.4972986] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
A new numerical scheme for RNA (ribonucleic acid) titration based on the Debye-Hückel framework for the salt description is proposed in an effort to reduce the computational costs for further applications to study protein-RNA systems. By means of different sets of Monte Carlo simulations, we demonstrated that this new scheme is able to correctly reproduce the experimental titration behavior and salt pKa shifts. In comparison with other theoretical approaches, similar or even better outcomes are achieved at much lower computational costs. The model was tested on the lead-dependent ribozyme, the branch-point helix, and the domain 5 from Azotobacter vinelandii Intron 5.
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Affiliation(s)
- Fernando Luís Barroso da Silva
- Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ave. do café, s/no, BR-14040-903 Ribeirão Preto, São Paulo, Brazil
| | - Philippe Derreumaux
- Laboratoire de Biochimie Theórique, UPR 9080 CNRS, Institut de Biologie Physico Chimique, Université Paris Diderot - Paris 7 et Université Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Samuela Pasquali
- Laboratoire de Biochimie Theórique, UPR 9080 CNRS, Institut de Biologie Physico Chimique, Université Paris Diderot - Paris 7 et Université Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, 75005 Paris, France
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23
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Seelam PP, Sharma P, Mitra A. Structural landscape of base pairs containing post-transcriptional modifications in RNA. RNA (NEW YORK, N.Y.) 2017; 23:847-859. [PMID: 28341704 PMCID: PMC5435857 DOI: 10.1261/rna.060749.117] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 03/23/2017] [Indexed: 05/20/2023]
Abstract
Base pairs involving post-transcriptionally modified nucleobases are believed to play important roles in a wide variety of functional RNAs. Here we present our attempts toward understanding the structural and functional role of naturally occurring modified base pairs using a combination of X-ray crystal structure database analysis, sequence analysis, and advanced quantum chemical methods. Our bioinformatics analysis reveals that despite their presence in all major secondary structural elements, modified base pairs are most prevalent in tRNA crystal structures and most commonly involve guanine or uridine modifications. Further, analysis of tRNA sequences reveals additional examples of modified base pairs at structurally conserved tRNA regions and highlights the conservation patterns of these base pairs in three domains of life. Comparison of structures and binding energies of modified base pairs with their unmodified counterparts, using quantum chemical methods, allowed us to classify the base modifications in terms of the nature of their electronic structure effects on base-pairing. Analysis of specific structural contexts of modified base pairs in RNA crystal structures revealed several interesting scenarios, including those at the tRNA:rRNA interface, antibiotic-binding sites on the ribosome, and the three-way junctions within tRNA. These scenarios, when analyzed in the context of available experimental data, allowed us to correlate the occurrence and strength of modified base pairs with their specific functional roles. Overall, our study highlights the structural importance of modified base pairs in RNA and points toward the need for greater appreciation of the role of modified bases and their interactions, in the context of many biological processes involving RNA.
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Affiliation(s)
- Preethi P Seelam
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology Hyderabad (IIIT-H), Gachibowli, Hyderabad, Telangana 500032, India
| | - Purshotam Sharma
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Abhijit Mitra
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology Hyderabad (IIIT-H), Gachibowli, Hyderabad, Telangana 500032, India
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24
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Halder A, Roy R, Bhattacharyya D, Mitra A. How Does Mg 2+ Modulate the RNA Folding Mechanism: A Case Study of the G:C W:W Trans Basepair. Biophys J 2017; 113:277-289. [PMID: 28506525 DOI: 10.1016/j.bpj.2017.04.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/18/2017] [Accepted: 04/21/2017] [Indexed: 12/30/2022] Open
Abstract
Reverse Watson-Crick G:C basepairs (G:C W:W Trans) occur frequently in different functional RNAs. This is one of the few basepairs whose gas-phase-optimized isolated geometry is inconsistent with the corresponding experimental geometry. Several earlier studies indicate that through post-transcriptional modification, direct protonation, or coordination with Mg2+, accumulation of positive charge near N7 of guanine can stabilize the experimental geometry. Interestingly, recent studies reveal significant variation in the position of putatively bound Mg2+. This, in conjunction with recently raised doubts regarding some of the Mg2+ assignments near the imino nitrogen of guanine, is suggestive of the existence of multiple Mg2+ binding modes for this basepair. Our detailed investigation of Mg2+-bound G:C W:W Trans pairs occurring in high-resolution RNA crystal structures shows that they are found in 14 different contexts, eight of which display Mg2+ binding at the Hoogsteen edge of guanine. Further examination of occurrences in these eight contexts led to the characterization of three different Mg2+ binding modes: 1) direct binding via N7 coordination, 2) direct binding via O6 coordination, and 3) binding via hydrogen-bonding interaction with the first-shell water molecules. In the crystal structures, the latter two modes are associated with a buckled and propeller-twisted geometry of the basepair. Interestingly, respective optimized geometries of these different Mg2+ binding modes (optimized using six different DFT functionals) are consistent with their corresponding experimental geometries. Subsequent interaction energy calculations at the MP2 level, and decomposition of its components, suggest that for G:C W:W Trans , Mg2+ binding can fine tune the basepair geometries without compromising with their stability. Our results, therefore, underline the importance of the mode of binding of Mg2+ ions in shaping RNA structure, folding and function.
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Affiliation(s)
- Antarip Halder
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad, India
| | - Rohit Roy
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad, India
| | | | - Abhijit Mitra
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad, India.
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Gleghorn ML, Zhao J, Turner DH, Maquat LE. Crystal structure of a poly(rA) staggered zipper at acidic pH: evidence that adenine N1 protonation mediates parallel double helix formation. Nucleic Acids Res 2016; 44:8417-24. [PMID: 27288442 PMCID: PMC5041459 DOI: 10.1093/nar/gkw526] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 06/01/2016] [Indexed: 12/22/2022] Open
Abstract
We have solved at 1.07 Å resolution the X-ray crystal structure of a polyriboadenylic acid (poly(rA)) parallel and continuous double helix. Fifty-nine years ago, double helices of poly(rA) were first proposed to form at acidic pH. Here, we show that 7-mer oligo(rA), i.e. rA7, hybridizes and overlaps in all registers at pH 3.5 to form stacked double helices that span the crystal. Under these conditions, rA7 forms well-ordered crystals, whereas rA6 forms fragile crystalline-like structures, and rA5, rA8 and rA11 fail to crystallize. Our findings support studies from ∼50 years ago: one showed using spectroscopic methods that duplex formation at pH 4.5 largely starts with rA7 and begins to plateau with rA8; another proposed a so-called ‘staggered zipper’ model in which oligo(rA) strands overlap in multiple registers to extend the helical duplex. While never shown, protonation of adenines at position N1 has been hypothesized to be critical for helix formation. Bond angles in our structure suggest that N1 is protonated on the adenines of every other rAMP−rAMP helix base pair. Our data offer new insights into poly(rA) duplex formation that may be useful in developing a pH sensor.
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Affiliation(s)
- Michael L Gleghorn
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Jianbo Zhao
- Department of Chemistry, University of Rochester, Rochester, NY 14627, USA Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Douglas H Turner
- Department of Chemistry, University of Rochester, Rochester, NY 14627, USA Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
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Ray A, Panigrahi S, Bhattacharyya D. A comparison of four different conformations adopted by human telomeric G-quadruplex using computer simulations. Biopolymers 2015; 105:83-99. [PMID: 26448055 DOI: 10.1002/bip.22751] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 10/01/2015] [Accepted: 10/03/2015] [Indexed: 01/06/2023]
Abstract
The telomeric G-quadruplexes for their unique structural features are considered as potential anticancer drug targets. These, however, exhibit structural polymorphism as different topology types for the intra-molecular G-quadruplexes from human telomeric G-rich sequences have been reported based on NMR spectroscopy and X-ray crystallography. These techniques provide detailed atomic-level information about the molecule but relative conformational stability of the different topologies remains unsolved. Therefore, to understand the conformational preference, we have carried out quantum chemical calculations on G-quartets; used all-atom molecular dynamics (MD) simulations and steered molecular dynamics (SMD) simulations to characterize the four human telomeric G-quadruplex topologies based on its G-tetrad core-types, viz., parallel, anti-parallel, mixed-(3 + 1)-form1 and mixed-(3 + 1)-form2. We have also studied a non-telomeric sequence along with these telomeric forms giving a comparison between the two G-rich forms. The structural properties such as base pairing, stacking geometry and backbone conformations have been analyzed. The quantum calculations indicate that presence of a sodium ion inside the G-tetrad plane or two potassium ions on both sides of the plane give it an overall planarity which is much needed for good stacking to form a helix. MD simulations indicate that capping of the G-tetrad core by the TTA loops keep the terminal guanine bases away from water. The SMD simulations along with equilibrium MD studies indicate that the parallel and non-telomeric forms are comparatively less stable. We could come to the conclusion that the anti-parallel form and also the mixed-(3 + 1)-form1 topology are most likely to represent the major conformation., 2016. © 2015 Wiley Periodicals, Inc. Biopolymers 105: 83-99, 2016.
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Affiliation(s)
- Angana Ray
- Computational Science Division, Saha Institute of Nuclear Physics, Kolkata, 700064, India
| | - Swati Panigrahi
- Computational Science Division, Saha Institute of Nuclear Physics, Kolkata, 700064, India
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Masoodi HR, Bagheri S, Abareghi M. The effects of tautomerization and protonation on the adenine-cytosine mismatches: a density functional theory study. J Biomol Struct Dyn 2015. [PMID: 26198186 DOI: 10.1080/07391102.2015.1072734] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
In the present work, we demonstrate the results of a theoretical study concerned with the question how tautomerization and protonation of adenine affect the various properties of adenine-cytosine mismatches. The calculations, in gas phase and in water, are performed at B3LYP/6-311++G(d,p) level. In gas phase, it is observed that any tautomeric form of investigated mismatches is more stabilized when adenine is protonated. As for the neutral mismatches, the mismatches containing amino form of cytosine and imino form of protonated adenine are more stable. The role of aromaticity on the stability of tautomeric forms of mismatches is investigated by NICS(1)ZZ index. The stability of mispairs decreases by going from gas phase to water. It can be explained using dipole moment parameter. The influence of hydrogen bonds on the stability of mismatches is examined by atoms in molecules and natural bond orbital analyses. In addition to geometrical parameters and binding energies, the study of the topological properties of electron charge density aids in better understanding of these mispairs.
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Affiliation(s)
- Hamid Reza Masoodi
- a Faculty of Science, Department of Chemistry , Vali-e-Asr University of Rafsanjan , P.O. Box 77176, Rafsanjan , Iran
| | - Sotoodeh Bagheri
- a Faculty of Science, Department of Chemistry , Vali-e-Asr University of Rafsanjan , P.O. Box 77176, Rafsanjan , Iran
| | - Mahsa Abareghi
- a Faculty of Science, Department of Chemistry , Vali-e-Asr University of Rafsanjan , P.O. Box 77176, Rafsanjan , Iran
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Bhattacharya S, Mittal S, Panigrahi S, Sharma P, S P P, Paul R, Halder S, Halder A, Bhattacharyya D, Mitra A. RNABP COGEST: a resource for investigating functional RNAs. DATABASE-THE JOURNAL OF BIOLOGICAL DATABASES AND CURATION 2015; 2015:bav011. [PMID: 25776022 PMCID: PMC4360618 DOI: 10.1093/database/bav011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Structural bioinformatics of RNA has evolved mainly in response to the rapidly accumulating evidence that non-(protein)-coding RNAs (ncRNAs) play critical roles in gene regulation and development. The structures and functions of most ncRNAs are however still unknown. Most of the available RNA structural databases rely heavily on known 3D structures, and contextually correlate base pairing geometry with actual 3D RNA structures. None of the databases provide any direct information about stabilization energies. However, the intrinsic interaction energies of constituent base pairs can provide significant insights into their roles in the overall dynamics of RNA motifs and structures. Quantum mechanical (QM) computations provide the only approach toward their accurate quantification and characterization. ‘RNA Base Pair Count, Geometry and Stability’ (http://bioinf.iiit.ac.in/RNABPCOGEST) brings together information, extracted from literature data, regarding occurrence frequency, experimental and quantum chemically optimized geometries, and computed interaction energies, for non-canonical base pairs observed in a non-redundant dataset of functional RNA structures. The database is designed to enable the QM community, on the one hand, to identify appropriate biologically relevant model systems and also enable the biology community to easily sift through diverse computational results to gain theoretical insights which could promote hypothesis driven biological research. Database URL:http://bioinf.iiit.ac.in/RNABPCOGEST
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Affiliation(s)
- Sohini Bhattacharya
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, and Computational Science Division, Saha Institute of Nuclear Physics (SINP), 1/AF Bidhannagar, Kolkata 700064, India
| | - Shriyaa Mittal
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, and Computational Science Division, Saha Institute of Nuclear Physics (SINP), 1/AF Bidhannagar, Kolkata 700064, India
| | - Swati Panigrahi
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, and Computational Science Division, Saha Institute of Nuclear Physics (SINP), 1/AF Bidhannagar, Kolkata 700064, India
| | - Purshotam Sharma
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, and Computational Science Division, Saha Institute of Nuclear Physics (SINP), 1/AF Bidhannagar, Kolkata 700064, India
| | - Preethi S P
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, and Computational Science Division, Saha Institute of Nuclear Physics (SINP), 1/AF Bidhannagar, Kolkata 700064, India
| | - Rahul Paul
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, and Computational Science Division, Saha Institute of Nuclear Physics (SINP), 1/AF Bidhannagar, Kolkata 700064, India
| | - Sukanya Halder
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, and Computational Science Division, Saha Institute of Nuclear Physics (SINP), 1/AF Bidhannagar, Kolkata 700064, India
| | - Antarip Halder
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, and Computational Science Division, Saha Institute of Nuclear Physics (SINP), 1/AF Bidhannagar, Kolkata 700064, India
| | - Dhananjay Bhattacharyya
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, and Computational Science Division, Saha Institute of Nuclear Physics (SINP), 1/AF Bidhannagar, Kolkata 700064, India
| | - Abhijit Mitra
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, and Computational Science Division, Saha Institute of Nuclear Physics (SINP), 1/AF Bidhannagar, Kolkata 700064, India
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Halder A, Bhattacharya S, Datta A, Bhattacharyya D, Mitra A. The role of N7 protonation of guanine in determining the structure, stability and function of RNA base pairs. Phys Chem Chem Phys 2015; 17:26249-63. [DOI: 10.1039/c5cp04894j] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Ab initio computations and bioinformatics studies reveal that stabilization of some important RNA structural motifs might involve N7 protonation of guanine.
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Affiliation(s)
- Antarip Halder
- Center for Computational Natural Sciences and Bioinformatics (CCNSB)
- International Institute of Information Technology (IIIT-H)
- Hyderabad 500032
- India
| | - Sohini Bhattacharya
- Center for Computational Natural Sciences and Bioinformatics (CCNSB)
- International Institute of Information Technology (IIIT-H)
- Hyderabad 500032
- India
| | - Ayan Datta
- Department of Spectroscopy
- Indian Association for the Cultivation of Science
- Kolkata 700032
- India
| | | | - Abhijit Mitra
- Center for Computational Natural Sciences and Bioinformatics (CCNSB)
- International Institute of Information Technology (IIIT-H)
- Hyderabad 500032
- India
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