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Flores S, Malý M, Hrebík D, Plevka P, Černý J. Are kuravirus capsid diameters quantized? The first all-atom genome tracing method for double-stranded DNA viruses. Nucleic Acids Res 2024; 52:e12. [PMID: 38084886 PMCID: PMC10853797 DOI: 10.1093/nar/gkad1153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 11/01/2023] [Accepted: 11/14/2023] [Indexed: 02/10/2024] Open
Abstract
The revolution in cryo-electron microscopy has resulted in unprecedented power to resolve large macromolecular complexes including viruses. Many methods exist to explain density corresponding to proteins and thus entire protein capsids have been solved at the all-atom level. However methods for nucleic acids lag behind, and no all-atom viral double-stranded DNA genomes have been published at all. We here present a method which exploits the spiral winding patterns of DNA in icosahedral capsids. The method quickly generates shells of DNA wound in user-specified, idealized spherical or cylindrical spirals. For transition regions, the method allows guided semiflexible fitting. For the kuravirus SU10, our method explains most of the density in a semiautomated fashion. The results suggest rules for DNA turns in the end caps under which two discrete parameters determine the capsid inner diameter. We suggest that other kuraviruses viruses may follow the same winding scheme, producing a discrete rather than continuous spectrum of capsid inner diameters. Our software may be used to explain the published density maps of other double-stranded DNA viruses and uncover their genome packaging principles.
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Affiliation(s)
- Samuel Coulbourn Flores
- Swedish University of Agricultural Sciences, Ulls Väg 26, Uppsala, and Stockholm University, Tomtebodavägen 23A, Solna, Sweden
| | - Michal Malý
- Institute of Biotechnology of the Czech Academy of Sciences, Prumyslova 595, Vestec 25250, Czech Republic
| | - Dominik Hrebík
- Central European Institute of Technology, Kamenice 753/5, Brno, Czech Republic
| | - Pavel Plevka
- Central European Institute of Technology, Kamenice 753/5, Brno, Czech Republic
| | - Jiří Černý
- Institute of Biotechnology of the Czech Academy of Sciences, Prumyslova 595, Vestec 25250, Czech Republic
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Flores SC, Alexiou A, Glaros A. Mining the Protein Data Bank to improve prediction of changes in protein-protein binding. PLoS One 2021; 16:e0257614. [PMID: 34727109 PMCID: PMC8562805 DOI: 10.1371/journal.pone.0257614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 09/05/2021] [Indexed: 12/23/2022] Open
Abstract
Predicting the effect of mutations on protein-protein interactions is important for relating structure to function, as well as for in silico affinity maturation. The effect of mutations on protein-protein binding energy (ΔΔG) can be predicted by a variety of atomic simulation methods involving full or limited flexibility, and explicit or implicit solvent. Methods which consider only limited flexibility are naturally more economical, and many of them are quite accurate, however results are dependent on the atomic coordinate set used. In this work we perform a sequence and structure based search of the Protein Data Bank to find additional coordinate sets and repeat the calculation on each. The method increases precision and Positive Predictive Value, and decreases Root Mean Square Error, compared to using single structures. Given the ongoing growth of near-redundant structures in the Protein Data Bank, our method will only increase in applicability and accuracy.
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Affiliation(s)
| | - Athanasios Alexiou
- Department of Computer Science and Biomedical Informatics, University of Thessaly, Volos, Greece
| | - Anastasios Glaros
- Eukaryotic Single Cell Genomics Facility, Science For Life Laboratory, Stockholm, Sweden
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3
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Poitevin F, Kushner A, Li X, Dao Duc K. Structural Heterogeneities of the Ribosome: New Frontiers and Opportunities for Cryo-EM. Molecules 2020; 25:E4262. [PMID: 32957592 PMCID: PMC7570653 DOI: 10.3390/molecules25184262] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 12/18/2022] Open
Abstract
The extent of ribosomal heterogeneity has caught increasing interest over the past few years, as recent studies have highlighted the presence of structural variations of the ribosome. More precisely, the heterogeneity of the ribosome covers multiple scales, including the dynamical aspects of ribosomal motion at the single particle level, specialization at the cellular and subcellular scale, or evolutionary differences across species. Upon solving the ribosome atomic structure at medium to high resolution, cryogenic electron microscopy (cryo-EM) has enabled investigating all these forms of heterogeneity. In this review, we present some recent advances in quantifying ribosome heterogeneity, with a focus on the conformational and evolutionary variations of the ribosome and their functional implications. These efforts highlight the need for new computational methods and comparative tools, to comprehensively model the continuous conformational transition pathways of the ribosome, as well as its evolution. While developing these methods presents some important challenges, it also provides an opportunity to extend our interpretation and usage of cryo-EM data, which would more generally benefit the study of molecular dynamics and evolution of proteins and other complexes.
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Affiliation(s)
- Frédéric Poitevin
- Department of LCLS Data Analytics, Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA;
| | - Artem Kushner
- Department of Mathematics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (A.K.); (X.L.)
- Department of Computer Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Xinpei Li
- Department of Mathematics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (A.K.); (X.L.)
- Department of Computer Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Khanh Dao Duc
- Department of Mathematics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (A.K.); (X.L.)
- Department of Computer Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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Sarkar M, Saha S. Structural insight into the role of novel SARS-CoV-2 E protein: A potential target for vaccine development and other therapeutic strategies. PLoS One 2020; 15:e0237300. [PMID: 32785274 PMCID: PMC7423102 DOI: 10.1371/journal.pone.0237300] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 07/25/2020] [Indexed: 01/15/2023] Open
Abstract
The outbreak of COVID-19 across the world has posed unprecedented and global challenges on multiple fronts. Most of the vaccine and drug development has focused on the spike proteins and viral RNA-polymerases and main protease for viral replication. Using the bioinformatics and structural modelling approach, we modelled the structure of the envelope (E)-protein of novel SARS-CoV-2. The E-protein of this virus shares sequence similarity with that of SARS- CoV-1, and is highly conserved in the N-terminus regions. Incidentally, compared to spike proteins, E proteins demonstrate lower disparity and mutability among the isolated sequences. Using homology modelling, we found that the most favorable structure could function as a gated ion channel conducting H+ ions. Combining pocket estimation and docking with water, we determined that GLU 8 and ASN 15 in the N-terminal region were in close proximity to form H-bonds which was further validated by insertion of the E protein in an ERGIC-mimic membrane. Additionally, two distinct "core" structures were visible, the hydrophobic core and the central core, which may regulate the opening/closing of the channel. We propose this as a mechanism of viral ion channeling activity which plays a critical role in viral infection and pathogenesis. In addition, it provides a structural basis and additional avenues for vaccine development and generating therapeutic interventions against the virus.
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Affiliation(s)
- Manish Sarkar
- Department of Biochemistry, Bose Institute, Kolkata, India
| | - Soham Saha
- Laboratory for Perception and Memory, Institut Pasteur, Paris, France
- Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR-3571), Paris, France
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5
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Molecular Dynamics Simulations Suggest a Non-Doublet Decoding Model of -1 Frameshifting by tRNA Ser3. Biomolecules 2019; 9:biom9110745. [PMID: 31752208 PMCID: PMC6920855 DOI: 10.3390/biom9110745] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/14/2019] [Accepted: 11/14/2019] [Indexed: 12/28/2022] Open
Abstract
In-frame decoding in the ribosome occurs through canonical or wobble Watson-Crick pairing of three mRNA codon bases (a triplet) with a triplet of anticodon bases in tRNA. Departures from the triplet-triplet interaction can result in frameshifting, meaning downstream mRNA codons are then read in a different register. There are many mechanisms to induce frameshifting, and most are insufficiently understood. One previously proposed mechanism is doublet decoding, in which only codon bases 1 and 2 are read by anticodon bases 34 and 35, which would lead to -1 frameshifting. In E. coli, tRNASer3GCU can induce -1 frameshifting at alanine (GCA) codons. The logic of the doublet decoding model is that the Ala codon's GC could pair with the tRNASer3's GC, leaving the third anticodon residue U36 making no interactions with mRNA. Under that model, a U36C mutation would still induce -1 frameshifting, but experiments refute this. We perform all-atom simulations of wild-type tRNASer3, as well as a U36C mutant. Our simulations revealed a hydrogen bond between U36 of the anticodon and G1 of the codon. The U36C mutant cannot make this interaction, as it lacks the hydrogen-bond-donating H3. The simulation thus suggests a novel, non-doublet decoding mechanism for -1 frameshifting by tRNASer3 at Ala codons.
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Spiridon L, Minh DDL. Hamiltonian Monte Carlo with Constrained Molecular Dynamics as Gibbs Sampling. J Chem Theory Comput 2017; 13:4649-4659. [PMID: 28892630 DOI: 10.1021/acs.jctc.7b00570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Compared to fully flexible molecular dynamics, simulations of constrained systems can use larger time steps and focus kinetic energy on soft degrees of freedom. Achieving ergodic sampling from the Boltzmann distribution, however, has proven challenging. Using recent generalizations of the equipartition principle and Fixman potential, here we implement Hamiltonian Monte Carlo based on constrained molecular dynamics as a Gibbs sampling move. By mixing Hamiltonian Monte Carlo based on fully flexible and torsional dynamics, we are able to reproduce free energy landscapes of simple model systems and enhance sampling of macrocycles.
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Affiliation(s)
- Laurentiu Spiridon
- Department of Chemistry, Illinois Institute of Technology , Chicago, Illinois 60616, United States.,Department of Bioinformatics and Structural Biochemistry, Institute of Biochemistry of the Romanian Academy , Bucharest 060031, Romania
| | - David D L Minh
- Department of Chemistry, Illinois Institute of Technology , Chicago, Illinois 60616, United States
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Cheng RR, Nordesjö O, Hayes RL, Levine H, Flores SC, Onuchic JN, Morcos F. Connecting the Sequence-Space of Bacterial Signaling Proteins to Phenotypes Using Coevolutionary Landscapes. Mol Biol Evol 2016; 33:3054-3064. [PMID: 27604223 PMCID: PMC5100047 DOI: 10.1093/molbev/msw188] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Two-component signaling (TCS) is the primary means by which bacteria sense and respond to the environment. TCS involves two partner proteins working in tandem, which interact to perform cellular functions whereas limiting interactions with non-partners (i.e., cross-talk). We construct a Potts model for TCS that can quantitatively predict how mutating amino acid identities affect the interaction between TCS partners and non-partners. The parameters of this model are inferred directly from protein sequence data. This approach drastically reduces the computational complexity of exploring the sequence-space of TCS proteins. As a stringent test, we compare its predictions to a recent comprehensive mutational study, which characterized the functionality of 204 mutational variants of the PhoQ kinase in Escherichia coli We find that our best predictions accurately reproduce the amino acid combinations found in experiment, which enable functional signaling with its partner PhoP. These predictions demonstrate the evolutionary pressure to preserve the interaction between TCS partners as well as prevent unwanted cross-talk. Further, we calculate the mutational change in the binding affinity between PhoQ and PhoP, providing an estimate to the amount of destabilization needed to disrupt TCS.
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Affiliation(s)
- R R Cheng
- Center for Theoretical Biological Physics, Rice University, Houston, TX
| | - O Nordesjö
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - R L Hayes
- Department of Biophysics, University of Michigan, Ann Arbor, MI
| | - H Levine
- Center for Theoretical Biological Physics, Rice University, Houston, TX.,Department of Bioengineering, Rice University, Houston, TX
| | - S C Flores
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - J N Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, TX .,Department of Physics and Astronomy, Rice University, Houston, TX.,Department of Chemistry, and Biosciences, Rice University, Houston, TX
| | - F Morcos
- Department of Biological Sciences and Center for Systems Biology, University of Texas at Dallas, Dallas, TX
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Dourado DFAR, Flores SC. Modeling and fitting protein-protein complexes to predict change of binding energy. Sci Rep 2016; 6:25406. [PMID: 27173910 PMCID: PMC4865953 DOI: 10.1038/srep25406] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 04/18/2016] [Indexed: 01/18/2023] Open
Abstract
It is possible to accurately and economically predict change in protein-protein interaction energy upon mutation (ΔΔG), when a high-resolution structure of the complex is available. This is of growing usefulness for design of high-affinity or otherwise modified binding proteins for therapeutic, diagnostic, industrial, and basic science applications. Recently the field has begun to pursue ΔΔG prediction for homology modeled complexes, but so far this has worked mostly for cases of high sequence identity. If the interacting proteins have been crystallized in free (uncomplexed) form, in a majority of cases it is possible to find a structurally similar complex which can be used as the basis for template-based modeling. We describe how to use MMB to create such models, and then use them to predict ΔΔG, using a dataset consisting of free target structures, co-crystallized template complexes with sequence identify with respect to the targets as low as 44%, and experimental ΔΔG measurements. We obtain similar results by fitting to a low-resolution Cryo-EM density map. Results suggest that other structural constraints may lead to a similar outcome, making the method even more broadly applicable.
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Affiliation(s)
- Daniel F A R Dourado
- Department of Cell and Molecular Biology, Computational and Systems Biology, Uppsala University, Biomedical Center Box 596, 751 24, Uppsala, Sweden
| | - Samuel Coulbourn Flores
- Department of Cell and Molecular Biology, Computational and Systems Biology, Uppsala University, Biomedical Center Box 596, 751 24, Uppsala, Sweden
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