1
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Ropii B, Bethasari M, Anshori I, Koesoema AP, Shalannanda W, Satriawan A, Setianingsih C, Akbar MR, Aditama R. The assessment of molecular dynamics results of three-dimensional RNA aptamer structure prediction. PLoS One 2023; 18:e0288684. [PMID: 37498889 PMCID: PMC10373999 DOI: 10.1371/journal.pone.0288684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 06/30/2023] [Indexed: 07/29/2023] Open
Abstract
Aptamers are single-stranded DNA or RNA that bind to specific targets such as proteins, thus having similar characteristics to antibodies. It can be synthesized at a lower cost, with no batch-to-batch variations, and is easier to modify chemically than antibodies, thus potentially being used as therapeutic and biosensing agents. The current method for RNA aptamer identification in vitro uses the SELEX method, which is considered inefficient due to its complex process. Computational models of aptamers have been used to predict and study the molecular interaction of modified aptamers to improve affinity. In this study, we generated three-dimensional models of five RNA aptamers from their sequence using mFold, RNAComposer web server, and molecular dynamics simulation. The model structures were then evaluated and compared with the experimentally determined structures. This study showed that the combination of mFold, RNAComposer, and molecular dynamics simulation could generate 14-16, 28, or 29 nucleotides length of 3D RNA aptamer with similar geometry and topology to the experimentally determined structures. The non-canonical basepair structure of the aptamer loop was formed through the MD simulation, which also improved the three-dimensional RNA aptamers model. Clustering analysis was recommended to choose the more representative model.
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Affiliation(s)
- Bejo Ropii
- School of Electrical Engineering and Informatics, Bandung Institute of Technology, Bandung, West Java, Indonesia
| | - Maulidwina Bethasari
- Department of Pharmacy, Universitas Muhammadiyah Bandung, Bandung, West Java, Indonesia
| | - Isa Anshori
- School of Electrical Engineering and Informatics, Bandung Institute of Technology, Bandung, West Java, Indonesia
- Research Center for Nanosciences and Nanotechnology (RCNN), Bandung Institute of Technology, Bandung, West Java, Indonesia
| | - Allya Paramita Koesoema
- School of Electrical Engineering and Informatics, Bandung Institute of Technology, Bandung, West Java, Indonesia
| | - Wervyan Shalannanda
- School of Electrical Engineering and Informatics, Bandung Institute of Technology, Bandung, West Java, Indonesia
| | - Ardianto Satriawan
- School of Electrical Engineering and Informatics, Bandung Institute of Technology, Bandung, West Java, Indonesia
| | - Casi Setianingsih
- Department of Computer Engineering, School of Electrical Engineering, Telkom University, Bandung Regency, West Java, Indonesia
| | - Mohammad Rizki Akbar
- Department of Cardiology and Vascular Medicine, Faculty of Medicine, Universitas Padjadjaran and Dr. Hasan Sadikin General Hospital, Bandung, West Java, Indonesia
| | - Reza Aditama
- Biochemistry Research Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Bandung, West Java, Indonesia
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2
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Ali Z, Goyal A, Jhunjhunwala A, Mitra A, Trant JF, Sharma P. Structural and Energetic Features of Base-Base Stacking Contacts in RNA. J Chem Inf Model 2023; 63:655-669. [PMID: 36635230 DOI: 10.1021/acs.jcim.2c01116] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Nucleobase π-π stacking is one of the crucial organizing interactions within three-dimensional (3D) RNA architectures. Characterizing the structural variability of these contacts in RNA crystal structures will help delineate their subtleties and their role in determining function. This analysis of different stacking geometries found in RNA X-ray crystal structures is the largest such survey to date; coupled with quantum-mechanical calculations on typical representatives of each possible stacking arrangement, we determined the distribution of stacking interaction energies. A total of 1,735,481 stacking contacts, spanning 359 of the 384 theoretically possible distinct stacking geometries, were identified. Our analysis reveals preferential occurrences of specific consecutive stacking arrangements in certain regions of RNA architectures. Quantum chemical calculations suggest that 88 of the 359 contacts possess intrinsically stable stacking geometries, whereas the remaining stacks require the RNA backbone or surrounding macromolecular environment to force their formation and maintain their stability. Our systematic analysis of π-π stacks in RNA highlights trends in the occurrence and localization of these noncovalent interactions and may help better understand the structural intricacies of functional RNA-based molecular architectures.
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Affiliation(s)
- Zakir Ali
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh160014, India
| | - Ambika Goyal
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh160014, India
| | - Ayush Jhunjhunwala
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad, Gachibowli, Hyderabad, Telangana500032, India
| | - Abhijit Mitra
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad, Gachibowli, Hyderabad, Telangana500032, India
| | - John F Trant
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, OntarioN9B 3P4, Canada
- Binary Star Research Services, LaSalle, OntarioN9J 3X8, Canada
| | - Purshotam Sharma
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh160014, India
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, OntarioN9B 3P4, Canada
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3
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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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4
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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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5
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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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6
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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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7
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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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8
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Effect of single-residue bulges on RNA double-helical structures: crystallographic database analysis and molecular dynamics simulation studies. J Mol Model 2017; 23:311. [DOI: 10.1007/s00894-017-3480-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 09/19/2017] [Indexed: 11/26/2022]
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9
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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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10
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Chawla M, Oliva R, Bujnicki JM, Cavallo L. An atlas of RNA base pairs involving modified nucleobases with optimal geometries and accurate energies. Nucleic Acids Res 2015; 43:6714-29. [PMID: 26117545 PMCID: PMC4538814 DOI: 10.1093/nar/gkv606] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 05/28/2015] [Indexed: 01/08/2023] Open
Abstract
Posttranscriptional modifications greatly enhance the chemical information of RNA molecules, contributing to explain the diversity of their structures and functions. A significant fraction of RNA experimental structures available to date present modified nucleobases, with half of them being involved in H-bonding interactions with other bases, i.e. ‘modified base pairs’. Herein we present a systematic investigation of modified base pairs, in the context of experimental RNA structures. To this end, we first compiled an atlas of experimentally observed modified base pairs, for which we recorded occurrences and structural context. Then, for each base pair, we selected a representative for subsequent quantum mechanics calculations, to find out its optimal geometry and interaction energy. Our structural analyses show that most of the modified base pairs are non Watson–Crick like and are involved in RNA tertiary structure motifs. In addition, quantum mechanics calculations quantify and provide a rationale for the impact of the different modifications on the geometry and stability of the base pairs they participate in.
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Affiliation(s)
- Mohit Chawla
- King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, Kaust Catalysis Center, Thuwal 23955-6900, Saudi Arabia
| | - Romina Oliva
- Department of Sciences and Technologies, University Parthenope of Naples, Centro Direzionale Isola C4, I-80143, Naples, Italy
| | - 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
| | - Luigi Cavallo
- King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, Kaust Catalysis Center, Thuwal 23955-6900, Saudi Arabia
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11
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Halder A, Halder S, Bhattacharyya D, Mitra A. Feasibility of occurrence of different types of protonated base pairs in RNA: a quantum chemical study. Phys Chem Chem Phys 2015; 16:18383-96. [PMID: 25070186 DOI: 10.1039/c4cp02541e] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Protonated nucleobases have significant roles in facilitating catalytic functions of RNA, and in stabilizing different structural motifs. Reported pKa values of nucleobase protonation suggest that the population of neutral nucleobases is 10(3)-10(4) times higher than that of protonated nucleobases under physiological conditions (pH ∼ 7.4). Therefore, a molecular level understanding of various putative roles of protonated nucleobases cannot be achieved without addressing the question of how their occurrence propensities and stabilities are related to the free energy costs associated with the process of protonation under physiological conditions. With water as the proton donor, we use advanced QM methods to evaluate the site specific protonation propensities of nucleobases in terms of their associated free energy changes (ΔGprot). Quantitative follow up on the energetics of base pair formation and database search for evaluating their occurrence frequencies, reveal a lack of correlation between base pair stability and occurrence propensities on the one hand, and ease of protonation on the other. For example, although N7 protonated adenine (ΔGprot = 40.0 kcal mol(-1)) is found to participate in stable base pairing, base pairs involving N7 protonated guanine (ΔGprot = 36.8 kcal mol(-1)), on geometry optimization, converge to a minima where guanine transfers its extra proton to its partner base. Such observations, along with examples of weak base pairs involving N3 protonation of cytosine (ΔGprot = 37.0 kcal mol(-1)) are rationalized by analysing the protonation induced charge redistributions which are found to significantly influence, both positively and negatively, the hydrogen bonding potentials of different functional sites of individual nucleobases. Protonation induced charge redistribution is also found to strongly influence (i) the aromatic character of the rings of the participating bases and (ii) hydrogen bonding potential of the free edges of the protonated base pair. Comprehensive analysis of a non-redundant RNA crystal structure dataset further reveals that, while availability of stabilization possibilities determine the feasibility of occurrence of protonated bases, their occurrence context and specific functional roles are important factors determining their occurrence propensities.
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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.
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12
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Mondal M, Mukherjee S, Halder S, Bhattacharyya D. Stacking geometry for non-canonical G:U wobble base pair containing dinucleotide sequences in RNA: dispersion-corrected DFT-D study. Biopolymers 2015; 103:328-38. [DOI: 10.1002/bip.22616] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 01/01/2015] [Accepted: 01/08/2015] [Indexed: 01/06/2023]
Affiliation(s)
- Manas Mondal
- Computational Science Division; Saha Institute of Nuclear Physics; 1/AF Bidhannagar Kolkata 700064 India
| | - Sanchita Mukherjee
- Computational Science Division; Saha Institute of Nuclear Physics; 1/AF Bidhannagar Kolkata 700064 India
| | - Sukanya Halder
- Computational Science Division; Saha Institute of Nuclear Physics; 1/AF Bidhannagar Kolkata 700064 India
| | - Dhananjay Bhattacharyya
- Computational Science Division; Saha Institute of Nuclear Physics; 1/AF Bidhannagar Kolkata 700064 India
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13
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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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14
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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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15
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Mládek A, Banáš P, Jurečka P, Otyepka M, Zgarbová M, Šponer J. Energies and 2'-Hydroxyl Group Orientations of RNA Backbone Conformations. Benchmark CCSD(T)/CBS Database, Electronic Analysis, and Assessment of DFT Methods and MD Simulations. J Chem Theory Comput 2013; 10:463-80. [PMID: 26579924 DOI: 10.1021/ct400837p] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Sugar-phosphate backbone is an electronically complex molecular segment imparting RNA molecules high flexibility and architectonic heterogeneity necessary for their biological functions. The structural variability of RNA molecules is amplified by the presence of the 2'-hydroxyl group, capable of forming multitude of intra- and intermolecular interactions. Bioinformatics studies based on X-ray structure database revealed that RNA backbone samples at least 46 substates known as rotameric families. The present study provides a comprehensive analysis of RNA backbone conformational preferences and 2'-hydroxyl group orientations. First, we create a benchmark database of estimated CCSD(T)/CBS relative energies of all rotameric families and test performance of dispersion-corrected DFT-D3 methods and molecular mechanics in vacuum and in continuum solvent. The performance of the DFT-D3 methods is in general quite satisfactory. The B-LYP-D3 method provides the best trade-off between accuracy and computational demands. B3-LYP-D3 slightly outperforms the new PW6B95-D3 and MPW1B95-D3 and is the second most accurate density functional of the study. The best agreement with CCSD(T)/CBS is provided by DSD-B-LYP-D3 double-hybrid functional, although its large-scale applications may be limited by high computational costs. Molecular mechanics does not reproduce the fine energy differences between the RNA backbone substates. We also demonstrate that the differences in the magnitude of the hyperconjugation effect do not correlate with the energy ranking of the backbone conformations. Further, we investigated the 2'-hydroxyl group orientation preferences. For all families, we conducted a QM and MM hydroxyl group rigid scan in gas phase and solvent. We then carried out set of explicit solvent MD simulations of folded RNAs and analyze 2'-hydroxyl group orientations of different backbone families in MD. The solvent energy profiles determined primarily by the sugar pucker match well with the distribution data derived from the simulations. The QM and MM energy profiles predict the same 2'-hydroxyl group orientation preferences. Finally, we demonstrate that the high energy of unfavorable and rarely sampled 2'-hydroxyl group orientations can be attributed to clashes between occupied orbitals.
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Affiliation(s)
- Arnošt Mládek
- Institute of Biophysics, Academy of Sciences of the Czech Republic , Královopolská 135, 612 65 Brno, Czech Republic
| | - Pavel Banáš
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , tr. 17. listopadu 12, 771 46, Olomouc, Czech Republic
| | - Petr Jurečka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , tr. 17. listopadu 12, 771 46, Olomouc, Czech Republic
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , tr. 17. listopadu 12, 771 46, Olomouc, Czech Republic
| | - Marie Zgarbová
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , tr. 17. listopadu 12, 771 46, Olomouc, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic , Královopolská 135, 612 65 Brno, Czech Republic.,CEITEC, Central European Institute of Technology , Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
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16
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Chawla M, Abdel-Azeim S, Oliva R, Cavallo L. Higher order structural effects stabilizing the reverse Watson-Crick Guanine-Cytosine base pair in functional RNAs. Nucleic Acids Res 2013; 42:714-26. [PMID: 24121683 PMCID: PMC3902895 DOI: 10.1093/nar/gkt800] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The G:C reverse Watson-Crick (W:W trans) base pair, also known as Levitt base pair in the context of tRNAs, is a structurally and functionally important base pair that contributes to tertiary interactions joining distant domains in functional RNA molecules and also participates in metabolite binding in riboswitches. We previously indicated that the isolated G:C W:W trans base pair is a rather unstable geometry, and that dicationic metal binding to the Guanine base or posttranscriptional modification of the Guanine can increase its stability. Herein, we extend our survey and report on other H-bonding interactions that can increase the stability of this base pair. To this aim, we performed a bioinformatics search of the PDB to locate all the occurencies of G:C trans base pairs. Interestingly, 66% of the G:C trans base pairs in the PDB are engaged in additional H-bonding interactions with other bases, the RNA backbone or structured water molecules. High level quantum mechanical calculations on a data set of representative crystal structures were performed to shed light on the structural stability and energetics of the various crystallographic motifs. This analysis was extended to the binding of the preQ1 metabolite to a preQ1-II riboswitch.
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Affiliation(s)
- Mohit Chawla
- Physical Sciences and Engineering Division, Kaust Catalysis Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia and Department of Sciences and Technologies, University of Naples 'Parthenope', Centro Direzionale Isola C4, I-80143, Naples, Italy
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17
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Das G, Lyngdoh RHD. Configuration of wobble base pairs having pyrimidines as anticodon wobble bases: significance for codon degeneracy. J Biomol Struct Dyn 2013; 32:1500-20. [PMID: 23968386 DOI: 10.1080/07391102.2013.824822] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Degeneracy of the genetic code was attributed by Crick to imprecise hydrogen-bonded base-pairing at the wobble position during codon-anticodon pairing. The Crick wobble rules define but do not explain the RNA base pair combinations allowed at this position. We select six pyrimidine bases functioning as anticodon wobble bases (AWBs) to study their H-bonded pairing properties with the four major RNA bases using density functional theory at the B3LYP/6-31G(d,p) level. This is done to assess the extent to which the configuration of a solitary RNA wobble base pair may in itself determine specificity and degeneracy of the genetic code by allowing or disallowing the given base pair during codon-anticodon pairing. Calculated values of select configuration markers for the base pairs screen well between allowed and disallowed base pairs for most cases examined here, where the base pair width emerges as an important factor. A few allowed wobble pairs invoke the involvement of RNA nucleoside conformation, as well as involvement of the exocyclic substituent in H-bonding. This study, however, cannot explain the disallowed status of the Ura⋯Gua wobble pair on the basis of configuration alone. Explanation of the allowed status of the V⋯Ura pair requires further study on the mediatory role of water molecules. Apart from these two cases, these computational results are sufficient, on the basis of base pair configuration alone, to account for the specificity and degeneracy of the genetic code for all known cases of codon-anticodon pairing which involve the pyrimidine AWBs studied here.
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Affiliation(s)
- Gunajyoti Das
- a Department of Chemistry , North-Eastern Hill University , Shillong , 793022 , India
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18
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Halder S, Bhattacharyya D. RNA structure and dynamics: a base pairing perspective. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2013; 113:264-83. [PMID: 23891726 DOI: 10.1016/j.pbiomolbio.2013.07.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 06/25/2013] [Accepted: 07/16/2013] [Indexed: 12/12/2022]
Abstract
RNA is now known to possess various structural, regulatory and enzymatic functions for survival of cellular organisms. Functional RNA structures are generally created by three-dimensional organization of small structural motifs, formed by base pairing between self-complementary sequences from different parts of the RNA chain. In addition to the canonical Watson-Crick or wobble base pairs, several non-canonical base pairs are found to be crucial to the structural organization of RNA molecules. They appear within different structural motifs and are found to stabilize the molecule through long-range intra-molecular interactions between basic structural motifs like double helices and loops. These base pairs also impart functional variation to the minor groove of A-form RNA helices, thus forming anchoring site for metabolites and ligands. Non-canonical base pairs are formed by edge-to-edge hydrogen bonding interactions between the bases. A large number of theoretical studies have been done to detect and analyze these non-canonical base pairs within crystal or NMR derived structures of different functional RNA. Theoretical studies of these isolated base pairs using ab initio quantum chemical methods as well as molecular dynamics simulations of larger fragments have also established that many of these non-canonical base pairs are as stable as the canonical Watson-Crick base pairs. This review focuses on the various structural aspects of non-canonical base pairs in the organization of RNA molecules and the possible applications of these base pairs in predicting RNA structures with more accuracy.
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Affiliation(s)
- Sukanya Halder
- Biophysics division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700 064, India
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19
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Song G, Bai FY, Xing N, Chen C, Shan H, Xing YH. Crystal engineering of multiple-component organic compound: Organic co-crystals of the functional groups of carboxyl and amino with persistent hydrogen bonding motifs. Chem Res Chin Univ 2013. [DOI: 10.1007/s40242-013-2327-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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20
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Panigrahi S, Pal R, Bhattacharyya D. Structure and energy of non-canonical basepairs: comparison of various computational chemistry methods with crystallographic ensembles. J Biomol Struct Dyn 2012; 29:541-56. [PMID: 22066539 DOI: 10.1080/07391102.2011.10507404] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Different types of non-canonical basepairs, in addition to the Watson-Crick ones, are observed quite frequently in RNA. Their importance in the three dimensional structure is not fully understood, but their various roles have been proposed by different groups. We have analyzed the energetics and geometry of 32 most frequently observed basepairs in the functional RNA crystal structures using different popular empirical, semi-empirical and ab initio quantum chemical methods and compared their optimized geometry with the crystal data. These basepairs are classified into three categories: polar, non-polar and sugar-mediated, depending on the types of atoms involved in hydrogen bonding. In case of polar basepairs, most of the methods give rise to optimized structures close to their initial geometry. The interaction energies also follow similar trends, with the polar ones having more attractive interaction energies. Some of the C-H...O/N hydrogen bond mediated non-polar basepairs are also found to be significantly stable in terms of their interaction energy values. Few polar basepairs, having amino or carboxyl groups not hydrogen bonded to anything, such as G:G H:W C, show large flexibility. Most of the non-polar basepairs, except A:G s:s T and A:G w:s C, are found to be stable; indicating C-H...O/N interaction also plays a prominent role in stabilizing the basepairs. The sugar mediated basepairs show variability in their structures, due to the involvement of flexible ribose sugar. These presumably indicate that the most of the polar basepairs along with few non-polar ones act as seed for RNA folding while few may act as some conformational switch in the RNA.
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Affiliation(s)
- Swati Panigrahi
- Biophysics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India
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21
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Spasic A, Serafini J, Mathews DH. The Amber ff99 Force Field Predicts Relative Free Energy Changes for RNA Helix Formation. J Chem Theory Comput 2012; 8:2497-2505. [PMID: 23112748 PMCID: PMC3482406 DOI: 10.1021/ct300240k] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The ability of the Amber ff99 force field to predict relative free energies of RNA helix formation was investigated. The test systems were three hexaloop RNA hairpins with identical loops and varying stems. The potential of mean force of stretching the hairpins from the native state to an extended conformation was calculated with umbrella sampling. Because the hairpins have identical loop sequence, the differences in free energy changes are only from the stem composition. The Amber ff99 force field was able to correctly predict the order of stabilities of the hairpins, although the magnitude of the free energy change is larger than that determined by optical melting experiments. The two measurements cannot be compared directly because the unfolded state in the optical melting experiments is a random coil, while the end state in the umbrella sampling simulations was an elongated chain. The calculations can be compared to reference data by using a thermodynamic cycle. By applying the thermodynamic cycle to the transitions between the hairpins using simulations and nearest neighbor data, agreement was found to be within the sampling error of simulations, thus demonstrating that ff99 force field is able to accurately predict relative free energies of RNA helix formation.
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Affiliation(s)
- Aleksandar Spasic
- Department of Biochemistry & Biophysics and Center for RNA Biology, University of Rochester Medical Center, Rochester, New York
| | - John Serafini
- Department of Biochemistry & Biophysics and Center for RNA Biology, University of Rochester Medical Center, Rochester, New York
| | - David H. Mathews
- Department of Biochemistry & Biophysics and Center for RNA Biology, University of Rochester Medical Center, Rochester, New York
- Department of Biostatistics & Computational Biology, University of Rochester Medical Center, Rochester, New York
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22
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Das G, Lyngdoh RHD. Role of wobble base pair geometry for codon degeneracy: purine-type bases at the anticodon wobble position. J Mol Model 2012; 18:3805-20. [PMID: 22399149 DOI: 10.1007/s00894-012-1385-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 02/15/2012] [Indexed: 02/07/2023]
Abstract
Codon degeneracy is a key feature of the genetic code, explained by Crick (J Mol Biol 19:548-555, 1966) in terms of imprecision of base pairing at the codon third position (the wobble position) of the codon-anticodon duplex. The Crick wobble rules define, but do not explain, which base pairs are allowed/disallowed at the wobble position of this duplex. This work examines whether the H-bonded configurations of solitary RNA base pairs can in themselves help decide which base pairs are allowed at the wobble position during codon-anticodon pairing. Taking the purine-type bases guanine, hypoxanthine, queuine and adenine as anticodon wobble bases, H-bonded pairing energies and optimized configurations of numerous RNA base pairs are calculated in gas and modeled aqueous phase at the B3LYP/6-31 G(d,p) level. Calculated descriptors of alignment of these solitary base pairs are able to screen between allowed and disallowed base pairs for all cases studied here, except two cases which invoke base-sugar interactions in the codon wobble nucleoside. The exclusion of adenine from the anticodon wobble position cannot be explained on the basis of pairing facility or base pair geometry. These DFT results thus account for the specificity and degeneracy of the genetic code for all cases involving guanine, hypoxanthine and queuine as anticodon wobble bases.
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Affiliation(s)
- Gunajyoti Das
- Department of Chemistry, North-Eastern Hill University, Shillong, 793022, India
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23
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Mládek A, Šponer JE, Kulhánek P, Lu XJ, Olson WK, Šponer J. Understanding the Sequence Preference of Recurrent RNA Building Blocks using Quantum Chemistry: The Intrastrand RNA Dinucleotide Platform. J Chem Theory Comput 2012; 8:335-347. [PMID: 22712001 PMCID: PMC3375708 DOI: 10.1021/ct200712b] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Folded RNA molecules are shaped by an astonishing variety of highly conserved noncanonical molecular interactions and backbone topologies. The dinucleotide platform is a widespread recurrent RNA modular building submotif formed by the side-by-side pairing of bases from two consecutive nucleotides within a single strand, with highly specific sequence preferences. This unique arrangement of bases is cemented by an intricate network of noncanonical hydrogen bonds and facilitated by a distinctive backbone topology. The present study investigates the gas-phase intrinsic stabilities of the three most common RNA dinucleotide platforms - 5'-GpU-3', ApA, and UpC - via state-of-the-art quantum-chemical (QM) techniques. The mean stability of base-base interactions decreases with sequence in the order GpU > ApA > UpC. Bader's atoms-in-molecules analysis reveals that the N2(G)…O4(U) hydrogen bond of the GpU platform is stronger than the corresponding hydrogen bonds in the other two platforms. The mixed-pucker sugar-phosphate backbone conformation found in most GpU platforms, in which the 5'-ribose sugar (G) is in the C2'-endo form and the 3'-sugar (U) in the C3'-endo form, is intrinsically more stable than the standard A-RNA backbone arrangement, partially as a result of a favorable O2'…O2P intra-platform interaction. Our results thus validate the hypothesis of Lu et al. (Lu Xiang-Jun, et al. Nucleic Acids Res. 2010, 38, 4868-4876), that the superior stability of GpU platforms is partially mediated by the strong O2'…O2P hydrogen bond. In contrast, ApA and especially UpC platform-compatible backbone conformations are rather diverse and do not display any characteristic structural features. The average stabilities of ApA and UpC derived backbone conformers are also lower than those of GpU platforms. Thus, the observed structural and evolutionary patterns of the dinucleotide platforms can be accounted for, to a large extent, by their intrinsic properties as described by modern QM calculations. In contrast, we show that the dinucleotide platform is not properly described in the course of atomistic explicit-solvent simulations. Our work also gives methodological insights into QM calculations of experimental RNA backbone geometries. Such calculations are inherently complicated by rather large data and refinement uncertainties in the available RNA experimental structures, which often preclude reliable energy computations.
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Affiliation(s)
- Arnošt Mládek
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic
| | - Judit E. Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic
- CEITEC - Central European Institute of Technology, Masaryk University, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
| | - Petr Kulhánek
- CEITEC - Central European Institute of Technology, Masaryk University, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, 611 37 Brno, Czech Republic
| | - Xiang-Jun Lu
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Wilma K. Olson
- Department of Chemistry & Chemical Biology, BioMaPS Institute for Quantitative Biology, Rutgers - The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Jiřĺ Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic
- CEITEC - Central European Institute of Technology, Masaryk University, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
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Zgarbová M, Jurečka P, Banáš P, Otyepka M, Sponer JE, Leontis NB, Zirbel CL, Sponer J. Noncanonical hydrogen bonding in nucleic acids. Benchmark evaluation of key base-phosphate interactions in folded RNA molecules using quantum-chemical calculations and molecular dynamics simulations. J Phys Chem A 2011; 115:11277-92. [PMID: 21910417 DOI: 10.1021/jp204820b] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
RNA molecules are stabilized by a wide range of noncanonical interactions that are not present in DNA. Among them, the recently classified base-phosphate (BPh) interactions belong to the most important ones. Twelve percent of nucleotides in the ribosomal crystal structures are involved in BPh interactions. BPh interactions are highly conserved and provide major constraints on RNA sequence evolution. Here we provide assessment of the energetics of BPh interactions using MP2 computations extrapolated to the complete basis set of atomic orbitals and corrected for higher-order electron correlation effects. The reference computations are compared with DFT-D and DFT-D3 approaches, the SAPT method, and the molecular mechanics force field. The computations, besides providing the basic benchmark for the BPh interactions, allow some refinements of the original classification, including identification of some potential doubly bonded BPh patterns. The reference computations are followed by analysis of some larger RNA fragments that consider the context of the BPh interactions. The computations demonstrate the complexity of interaction patterns utilizing the BPh interactions in real RNA structures. The BPh interactions are often involved in intricate interaction networks. We studied BPh interactions of protonated adenine that can contribute to catalysis of hairpin ribozyme, the key BPh interaction in the S-turn motif of the sarcin-ricin loop, which may predetermine the S-turn topology and complex BPh patterns from the glmS riboswitch. Finally, the structural stability of BPh interactions in explicit solvent molecular dynamics simulations is assessed. The simulations well preserve key BPh interactions and allow dissection of structurally/functionally important water-meditated BPh bridges, which could not be considered in earlier bioinformatics classification of BPh interactions.
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Affiliation(s)
- Marie Zgarbová
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University, Olomouc, Czech Republic
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25
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Churchill CDM, Wetmore SD. Developing a computational model that accurately reproduces the structural features of a dinucleoside monophosphate unit within B-DNA. Phys Chem Chem Phys 2011; 13:16373-83. [PMID: 21842033 DOI: 10.1039/c1cp21689a] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The ability of a dinucleoside monophosphate to mimic the conformation of B-DNA was tested using a combination of different phosphate models (anionic, neutral, counterion), environments (gas, water), and density functionals (B3LYP, MPWB1K, M06-2X) with the 6-31G(d,p) basis set. Three sequences (5'-GX(Py)-3', where X(Py) = T, U or (Br)U) were considered, which vary in the (natural or modified) 3' pyrimidine nucleobase (X(Py)). These bases were selected due to their presence in natural DNA, structural similarity to T and/or applications in radical-initiated anti-tumour therapies. The accuracy of each of the 54 model, method and sequence combinations was judged based on the ability to reproduce key structural features of natural B-DNA, including the stacked base-base orientation and important backbone torsion angles. B3LYP yields distorted or tilted relative base-base orientations, while many computational challenges were encountered for MPWB1K. Despite wide use in computational studies of DNA, the neutral (protonated) phosphate model could not consistently predict a stacked arrangement for all sequences. In contrast, stacked base-base arrangements were obtained for all sequences with M06-2X in conjunction with both the anionic and (sodium) counterion phosphate models. However, comparison of calculated and experimental backbone conformations reveals the charge-neutralized counterion phosphate model best mimics B-DNA. Structures optimized with implicit solvent (water) are comparable to gas-phase structures, which suggests similar results should be obtained in an environment of intermediate polarity. We recommend the use of either gas-phase or water M06-2X optimizations with the counterion phosphate model to study the structure and/or reactivity of natural or modified DNA with a dinucleoside monophosphate.
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Affiliation(s)
- Cassandra D M Churchill
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, Canada T1K 3M4
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Chawla M, Sharma P, Halder S, Bhattacharyya D, Mitra A. Protonation of base pairs in RNA: context analysis and quantum chemical investigations of their geometries and stabilities. J Phys Chem B 2011; 115:1469-84. [PMID: 21254753 DOI: 10.1021/jp106848h] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Base pairs involving protonated nucleobases play important roles in mediating global macromolecular conformational changes and in facilitation of catalysis in a variety of functional RNA molecules. Here we present our attempts at understanding the role of such base pairs by detecting possible protonated base pairs in the available RNA crystal structures using BPFind software, in their specific structural contexts, and by the characterization of their geometries, interaction energies, and stabilities using advanced quantum chemical computations. We report occurrences of 18 distinct protonated base pair combinations from a representative data set of RNA crystal structures and propose a theoretical model for one putative base pair combination. Optimization of base pair geometries was carried out at the B3LYP/cc-pVTZ level, and the BSSE corrected interaction energies were calculated at the MP2/aug-cc-pVDZ level of theory. The geometries for each of the base pairs were characterized in terms of H-bonding patterns observed, rmsd values observed on optimization, and base pair geometrical parameters. In addition, the intermolecular interaction in these complexes was also analyzed using Morokuma energy decomposition. The gas phase interaction energies of the base pairs range from -24 to -49 kcal/mol and reveal the dominance of Hartree-Fock component of interaction energy constituting 73% to 98% of the total interaction energy values. On the basis of our combined bioinformatics and quantum chemical analysis of different protonated base pairs, we suggest resolution of structural ambiguities and correlate their geometric and energetic features with their structural and functional roles. In addition, we also examine the suitability of specific base pairs as key elements in molecular switches and as nucleators for higher order structures such as base triplets and quartets.
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Affiliation(s)
- Mohit Chawla
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H) Gachibowli, Hyderabad 500032, India
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Šponer J, Šponer JE, Petrov AI, Leontis NB. Quantum chemical studies of nucleic acids: can we construct a bridge to the RNA structural biology and bioinformatics communities? J Phys Chem B 2010; 114:15723-41. [PMID: 21049899 PMCID: PMC4868365 DOI: 10.1021/jp104361m] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In this feature article, we provide a side-by-side introduction for two research fields: quantum chemical calculations of molecular interaction in nucleic acids and RNA structural bioinformatics. Our main aim is to demonstrate that these research areas, while largely separated in contemporary literature, have substantial potential to complement each other that could significantly contribute to our understanding of the exciting world of nucleic acids. We identify research questions amenable to the combined application of modern ab initio methods and bioinformatics analysis of experimental structures while also assessing the limitations of these approaches. The ultimate aim is to attain valuable physicochemical insights regarding the nature of the fundamental molecular interactions and how they shape RNA structures, dynamics, function, and evolution.
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Affiliation(s)
- Jiří Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 61265 Brno, Czech Republic
| | - Judit E. Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 61265 Brno, Czech Republic
| | - Anton I. Petrov
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA
| | - Neocles B. Leontis
- Department of Chemistry, Bowling Green State University, Bowling Green, OH 43403, USA
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Sharma P, Chawla M, Sharma S, Mitra A. On the role of Hoogsteen:Hoogsteen interactions in RNA: ab initio investigations of structures and energies. RNA (NEW YORK, N.Y.) 2010; 16:942-957. [PMID: 20354152 PMCID: PMC2856888 DOI: 10.1261/rna.1919010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Accepted: 01/27/2010] [Indexed: 05/28/2023]
Abstract
We use a combination of database analysis and quantum chemical studies to investigate the role of cis and trans Hoogsteen:Hoogsteen (H:H) base pairs and associated higher-order structures in RNA. We add three new examples to the list of previously identified base-pair combinations belonging to these families and, in addition to contextual classification and characterization of their structural and energetic features, we compare their interbase interaction energies and propensities toward participation in triplets and quartets. We find that some base pairs, which are nonplanar in their isolated minimum energy geometries, attain planarity and stability upon triplet formation. A:A H:H trans is the most frequent H:H combination in RNA structures. This base pair occurs at many distinct positions in known rRNA structures, where it helps in the interaction of ribosomal domains in the 50S subunit. It is also present as a part of tertiary interaction in tRNA structures. Although quantum chemical studies suggest an intrinsically nonplanar geometry for this base pair in isolated form, it has the tendency to attain planar geometry in RNA crystal structures by forming higher-order tertiary interactions or in the presence of additional base-phosphate interactions. The tendency of this base pair to form such additional interactions may be helpful in bringing together different segments of RNA, thus making it suitable for the role of facilitator for RNA folding. This also explains the high occurrence frequency of this base pair among all H:H interactions.
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Affiliation(s)
- Purshotam Sharma
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology (IIIT-H), Gachibowli, Hyderabad 500032, India
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