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Negi I, Singh B, Singh Mahmi A, Sharma P. Structural Properties of Hachimoji Nucleic Acids and Their Building Blocks: Comparison of Genetic Systems with Four, Six and Eight Alphabets. Chemphyschem 2023; 24:e202200714. [PMID: 36315394 DOI: 10.1002/cphc.202200714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/29/2022] [Indexed: 11/07/2022]
Abstract
Expansion of the genetic alphabet is an ambitious goal. A recent breakthrough has led to the eight-base (hachimoji) genetics having canonical and unnatural bases. However, very little is known on the molecular-level features that facilitate the candidature of unnatural bases as genetic alphabets. Here we amalgamated DFT calculations and MD simulations to analyse the properties of the constituents of hachimoji DNA and RNA. DFT reveals the dominant syn conformation for isolated unnatural deoxyribonucleosides and at the 5'-end of oligonucleotides, although an anti/syn mixture is predicted at the nonterminal and 3'-terminal positions. However, isolated ribonucleotides prefer an anti/syn mixture, but mostly prefer anti conformation at the nonterminal positions. Further, the canonical base pairing combinations reveals significant strength, which may facilitate replication of hachimoji DNA. We also identify noncanonical base pairs that can better tolerate the substitution of unnatural pairs in RNA. Stacking strengths of 51 dimers reveals higher average stacking stabilization of dimers of hachimoji bases than canonical bases, which provides clues for choosing energetically stable sequences. A total of 14.4 μs MD simulations reveal the influence of solvent on the properties of hachimoji oligonucleotides and point to the likely fidelity of replication of hachimoji DNA. Our results pinpoint the features that explain the experimentally observed stability of hachimoji DNA.
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Affiliation(s)
- Indu Negi
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India
| | - Bimaldeep Singh
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India
| | - Amanpreet Singh Mahmi
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India
| | - Purshotam Sharma
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India.,Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Ave., Windsor, ON, N9B 3P4, Canada
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Sharma S, Arya A, Cruz R, Cleaves II HJ. Automated Exploration of Prebiotic Chemical Reaction Space: Progress and Perspectives. Life (Basel) 2021; 11:1140. [PMID: 34833016 PMCID: PMC8624352 DOI: 10.3390/life11111140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 12/12/2022] Open
Abstract
Prebiotic chemistry often involves the study of complex systems of chemical reactions that form large networks with a large number of diverse species. Such complex systems may have given rise to emergent phenomena that ultimately led to the origin of life on Earth. The environmental conditions and processes involved in this emergence may not be fully recapitulable, making it difficult for experimentalists to study prebiotic systems in laboratory simulations. Computational chemistry offers efficient ways to study such chemical systems and identify the ones most likely to display complex properties associated with life. Here, we review tools and techniques for modelling prebiotic chemical reaction networks and outline possible ways to identify self-replicating features that are central to many origin-of-life models.
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Affiliation(s)
- Siddhant Sharma
- Blue Marble Space Institute of Science, Seattle, WA 98154, USA; (S.S.); (A.A.); (R.C.)
- Department of Biochemistry, Deshbandhu College, University of Delhi, New Delhi 110019, India
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Aayush Arya
- Blue Marble Space Institute of Science, Seattle, WA 98154, USA; (S.S.); (A.A.); (R.C.)
- Department of Physics, Lovely Professional University, Jalandhar-Delhi GT Road, Phagwara 144001, India
| | - Romulo Cruz
- Blue Marble Space Institute of Science, Seattle, WA 98154, USA; (S.S.); (A.A.); (R.C.)
- Big Data Laboratory, Information and Communications Technology Center (CTIC), National University of Engineering, Amaru 210, Lima 15333, Peru
| | - Henderson James Cleaves II
- Blue Marble Space Institute of Science, Seattle, WA 98154, USA; (S.S.); (A.A.); (R.C.)
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8550, Japan
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Negi I, Mahmi AS, Seelam Prabhakar P, Sharma P. Molecular Dynamics Simulations of the Aptamer Domain of Guanidinium Ion Binding Riboswitch ykkC-III: Structural Insights into the Discrimination of Cognate and Alternate Ligands. J Chem Inf Model 2021; 61:5243-5255. [PMID: 34609872 DOI: 10.1021/acs.jcim.1c01022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Guanidinium ion is a toxic cellular metabolite. The ykkC-III riboswitch, an mRNA stretch, regulates the gene expression by undergoing a conformational change in response to the binding of a free guanidinium ion and thereby plays a potentially important role in alleviating guanidinium toxicity in cells. An experimental crystal structure of the guanidinium-bound aptamer domain of the riboswitch from Thermobifida Fusca revealed the overall RNA architecture and mapped the specific noncovalent interactions that stabilize the ligand within the binding pocket aptamer. However, details of how the aptamer domain discriminates the cognate ligand from its closest structurally analogous physiological metabolites (arginine and urea), and how the binding of cognate ligand arrays information from the aptamer domain to the expression platform for regulating the gene expression, are not well understood. To fill this void, we perform a cumulative of 2 μs all-atom explicit-solvent molecular dynamics (MD) simulations on the full aptamer domain, augmented with quantum-chemical calculations on the ligand-binding pocket, to compare the structural and dynamical details of the guanidinium-bound state with the arginine or urea bound states, as well as the unbound (open) state. Analysis of the ligand-binding pocket reveals that due to unfavorable interactions with the binding-pocket residues, urea cannot bind the aptamer domain and thereby cannot alter the gene expression. Although interaction of the guanidyl moiety of arginine within the binding pocket is either comparable or stronger than the guanidinium ion, additional non-native hydrogen-bonding networks, as well as differences in the dynamical details of the arginine-bound state, explain why arginine cannot transmit the information from the aptamer domain to the expression platform. Based on our simulations, we propose a mechanism of how the aptamer domain communicates with the expression platform. Overall, our work provides interesting insights into the ligand recognition by a specific class of riboswitches and may hopefully inspire future studies to further understand the gene regulation by riboswitches.
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Affiliation(s)
- Indu Negi
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Amanpreet Singh Mahmi
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Preethi Seelam Prabhakar
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology (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
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Kaur S, Grover P, Wetmore SD, Sharma P. Role of Stacking Interactions in the Stability of Primitive Genetics: A Quantum Chemical View. J Chem Inf Model 2021; 61:4321-4330. [PMID: 34491053 DOI: 10.1021/acs.jcim.1c00276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The origin of genetic material on earth is an age-old, entangled mystery that lacks a unanimous explanation. Recent studies have suggested that noncanonical bases such as barbituric acid (BA), melamine (MM), cyanuric acid (CA), and 2,4,6-triaminopyrimidine (TAP) may have undergone molecular selection within the "prebiotic soup" to spontaneously form supramolecular assemblies, which then covalently assembled into an RNA-like polymer (preRNA). However, information on the role of intrinsic interactions of these candidate heterocycles in their molecular selection as the components of preRNA, and the subsequent transition from preRNA to RNA, is currently missing in the literature. To fill this gap in our knowledge on the origin and evolution of primitive genetics, the present work employs density functional theory (B3LYP-D3) to evaluate and compare the stacking propensities of dimers containing prebiotic noncanonical (BA, MM, CA, and TAP) and/or canonical RNA bases (A, C, G, and U). Our detailed analysis of the variation in stacking strength with respect to four characteristic geometrical parameters between the monomers [i.e., the vertical distance, the angle of rotation, and (two) displacements in the x and y directions] reveals that stacking between nonidentical bases is preferred over identical bases for both prebiotic-prebiotic and canonical-canonical dimers. This not only underscores the similarity between the fundamental chemical properties of preRNA and RNA constituents but also supports the likelihood of the evolution of modern (RNA) genetics from primitive (preRNA) genetics. Furthermore, greater average stacking stabilization of canonical dimers than that of dimers containing one canonical and one preRNA nucleobase (by ∼5 kJ mol-1) or dimers solely containing preRNA nucleobases (by ∼12 kJ mol-1) indicates that enhanced stacking is an important factor that may have spurred the evolution of preRNA to an intermediate informational polymer to RNA. More importantly, our study identifies the central roles of CA, BA, and TAP in stacking stabilization within the preRNA and of BA in stacking interactions within the intermediate polymers and suggests that these heterocycles may have played distinct roles in various stages during the evolution from preRNA to RNA. Overall, our results highlight the significance of stacking interactions in the selection of nucleobase components of preRNA.
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Affiliation(s)
- Sarabjeet Kaur
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Payal Grover
- Department of Chemistry, Dayanand Anglo-Vedic (DAV) College, Sector 10, Chandigarh 16011, India
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Purshotam Sharma
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
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Kagra D, Mahmi AS, Kumar NVS, Prabhakar PS, Sharma P. Influence of the Number, Nature and Position of Methyl Posttranscriptional Modifications on Nucleobase Stacking in RNA. Chemphyschem 2021; 22:1622-1630. [PMID: 34101319 DOI: 10.1002/cphc.202100333] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/30/2021] [Indexed: 01/08/2023]
Abstract
DFT calculations are employed to quantify the influence of the presence, number, nature, and position of posttranscriptional methylation on stacking strength of RNA bases. We carry out detailed potential energy scans of the variation in stacking energies with characteristic geometrical parameters in three categories of forty stacked dimers - canonical base homodimers (N||N), methylated base homodimers (mN||mN) and heterodimers of canonical bases and methylated counterparts (N||mN). Our analysis reveals that neutral methylation invariably enhances the stacking of bases. Further, N||mN stacking is stronger than mN||mN stacking and charged N||mN exhibit strongest stacking among all dimers. This indicates that methylations greatly enhance stacking when dispersed in RNA sequences containing identical bases. Comparison of stacks involving singly- and doubly-methylated purines reveal that incremental methylation enhances the stacking in neutral dimers. Although methylation at the carbon position of neutral pyrimidine dimers greatly enhances the stacking, methylation on the 5-membered ring imparts better stacking compared to methylation on the 6-membered ring in adenine dimers. However, methylation at the ring nitrogen (N1 ) provides better stacking than the amino group (N2 ) in guanine dimers. Our results thus highlight subtle structural effects of methylation on RNA base stacking and will enhance our understanding of the physicochemical principles of RNA structure and dynamics.
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Affiliation(s)
- Deepika Kagra
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India
| | - Amanpreet Singh Mahmi
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India
| | - N V Suresh Kumar
- Department of Humanities and Sciences (Physics), VNR Vignana Jyothi Institute of Engineering and Technology, Hyderabad, 500090, India
| | - Preethi Seelam Prabhakar
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, T1K3M4, Canada
| | - Purshotam Sharma
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India
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Kagra D, Prabhakar PS, Sharma KD, Sharma P. Structural Patterns and Stabilities of Hydrogen-Bonded Pairs Involving Ribonucleotide Bases and Arginine, Glutamic Acid, or Glutamine Residues of Proteins from Quantum Mechanical Calculations. ACS OMEGA 2020; 5:3612-3623. [PMID: 32118177 PMCID: PMC7045552 DOI: 10.1021/acsomega.9b04083] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 01/28/2020] [Indexed: 06/10/2023]
Abstract
Ribonucleotide:protein interactions play crucial roles in a number of biological processes. Unlike the RNA:protein interface where van der Waals contacts are prevalent, the recognition of a single ribonucleotide such as ATP by a protein occurs predominantly through hydrogen-bonding interactions. As a first step toward understanding the role of hydrogen bonding in ribonucleotide:protein recognition, the present work employs density functional theory to provide a detailed quantum-mechanical analysis of the structural and energetic characteristics of 18 unique hydrogen-bonded pairs involving the nucleobase/nucleoside moiety of four canonical ribonucleotides and the side chains of three polar amino-acid residues (arginine, glutamine, and glutamic acid) of proteins. In addition, we model five new pairs that are till now not observed in crystallographically identified ribonucleotide:protein complexes but may be identified in complexes crystallized in the future. We critically examine the characteristics of each pair in its ribonucleotide:protein crystal structure occurrence and (gas phase and water phase) optimized intrinsic structure. We further evaluated the interaction energy of each pair and characterized the associated hydrogen bonds using a number of quantum mechanics-based relationships including natural bond orbital analysis, quantum theory atoms in molecules analysis, Iogansen relationships, Nikolaienko-Bulavin-Hovorun relationships, and noncovalent interaction-reduced density gradient analysis. Our analyses reveal rich variability in hydrogen bonds in the crystallographic as well as intrinsic structure of each pair, which includes conventional O/N-H···N/O and C-H···O hydrogen bonds as well as donor/acceptor-bifurcated hydrogen bonds. Further, we identify five combinations of nucleobase and amino acid moieties; each of which exhibits at least two alternate (i.e., multimodal) structures that interact through the same nucleobase edge. In fact, one such pair exhibits four multimodal structures; one of which possesses unconventional "amino-acceptor" hydrogen bonding with comparable (-9.4 kcal mol-1) strength to the corresponding conventional (i.e., amino:donor) structure (-9.2 kcal mol-1). This points to the importance of amino-acceptor hydrogen bonds in RNA:protein interactions and suggests that such interactions must be considered in the future while studying the dynamics in the context of molecular recognition. Overall, our study provides preliminary insights into the intrinsic features of ribonucleotide:amino acid interactions, which may help frame a clearer picture of the molecular basis of RNA:protein recognition and further appreciate the role of such contacts in biology.
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Affiliation(s)
- Deepika Kagra
- Computational
Biochemistry Laboratory, Department of Chemistry, and Centre for Advanced
Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Preethi Seelam Prabhakar
- Center
for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology
Hyderabad (IIIT-H), Gachibowli, Hyderabad, Telangana 500032, India
| | - Karan Deep Sharma
- Computational
Biochemistry Laboratory, Department of Chemistry, and Centre for Advanced
Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Purshotam Sharma
- Computational
Biochemistry Laboratory, Department of Chemistry, and Centre for Advanced
Studies in Chemistry, Panjab University, Chandigarh 160014, India
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