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Efthymiou T, Gavette J, Stoop M, De Riccardis F, Froeyen M, Herdewijn P, Krishnamurthy R. Chimeric XNA: An Unconventional Design for Orthogonal Informational Systems. Chemistry 2018; 24:12811-12819. [PMID: 29901248 DOI: 10.1002/chem.201802287] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 06/12/2018] [Indexed: 10/14/2022]
Abstract
The paradigm of homogenous-sugar-backbone of RNA and DNA has reliably guided the construction of many functional and useful xeno nucleic acid (XNA) systems to date. Deviations from this monotonous and canonical design, in many cases, results in oligonucleotide systems that lack base pairing with themselves, or with RNA or DNA. Here we show that nucleotides of two such compromised XNA systems can be combined with RNA and DNA in specific patterns to produce chimeric-backbone oligonucleotides, which in certain cases demonstrate base pairing properties comparable to-or stronger than-canonical systems, while also altering the conventional Watson-Crick pairing behavior. The unorthodox pairing properties generated from these chimeric sugar-backbone oligonucleotides suggest a counterintuitive approach of creating modules consisting of non-base pairing XNAs with RNA/DNA in a set pattern. This strategy has the potential to increase the diversity of unconventional nucleic acids leading to orthogonal backbone-sequence-controlled informational systems.
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Affiliation(s)
- Tim Efthymiou
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.,NSF/NASA Center for Chemical Evolution, Atlanta, GA, 30332, USA
| | - Jesse Gavette
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.,NSF/NASA Center for Chemical Evolution, Atlanta, GA, 30332, USA
| | - Matthias Stoop
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.,NSF/NASA Center for Chemical Evolution, Atlanta, GA, 30332, USA
| | - Francesco De Riccardis
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.,NSF/NASA Center for Chemical Evolution, Atlanta, GA, 30332, USA.,Department of Chemistry and Biology, University of Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano, Salerno, Italy
| | - Mathy Froeyen
- Department of Medicinal Chemistry, Institute for Medical Research, KU Leuven, Herestraat, 49, Leuven, 3000, Belgium
| | - Piet Herdewijn
- Department of Medicinal Chemistry, Institute for Medical Research, KU Leuven, Herestraat, 49, Leuven, 3000, Belgium
| | - Ramanarayanan Krishnamurthy
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.,NSF/NASA Center for Chemical Evolution, Atlanta, GA, 30332, USA
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Zhang L. Different dynamics and pathway of disulfide bonds reduction of two human defensins, a molecular dynamics simulation study. Proteins 2017; 85:665-681. [PMID: 28106297 DOI: 10.1002/prot.25247] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 01/05/2017] [Accepted: 01/09/2017] [Indexed: 11/11/2022]
Abstract
Human defensins are a class of antimicrobial peptides that are crucial components of the innate immune system. Both human α defensin type 5 (HD5) and human β defensin type 3 (hBD-3) have 6 cysteine residues which form 3 pairs of disulfide bonds in oxidizing condition. Disulfide bond linking is important to the protein structure stabilization, and the disulfide bond linking and breaking order have been shown to influence protein function. In this project, microsecond long molecular dynamics simulations were performed to study the structure and dynamics of HD5 and hBD-3 wildtype and analogs which have all 3 disulfide bonds released in reducing condition. The structure of hBD-3 was found to be more dynamic and flexible than HD5, based on RMSD, RMSF, and radius of gyration calculations. The disulfide bridge breaking order of HD5 and hBD-3 in reducing condition was predicted by two kinds of methods, which gave consistent results. It was found that the disulfide bonds breaking pathways for HD5 and hBD-3 are very different. The breaking of disulfide bonds can influence the dimer interface by making the dimer structure less stable for both kinds of defensin. In order to understand the difference in dynamics and disulfide bond breaking pathway, hydrophilic and hydrophobic accessible surface areas (ASA), buried surface area between cysteine pairs, entropy of cysteine pairs, and internal energy were calculated. Comparing to the wildtype, hBD-3 analog is more hydrophobic, while HD5 is more hydrophilic. For hBD-3, the disulfide breaking is mainly entropy driven, while other factors such as the solvation effects may take the major role in controlling HD5 disulfide breaking pathway. Proteins 2017; 85:665-681. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Liqun Zhang
- Department of Chemical Engineering, Tennessee Technological University, Cookeville, TN, 38505
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Nakano M, Tateishi-Karimata H, Tanaka S, Tama F, Miyashita O, Nakano SI, Sugimoto N. Local thermodynamics of the water molecules around single- and double-stranded DNA studied by grid inhomogeneous solvation theory. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.08.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Shrestha P, Wereszczynski J. Discerning the catalytic mechanism of Staphylococcus aureus sortase A with QM/MM free energy calculations. J Mol Graph Model 2016; 67:33-43. [PMID: 27172839 DOI: 10.1016/j.jmgm.2016.04.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 04/08/2016] [Accepted: 04/09/2016] [Indexed: 10/21/2022]
Abstract
Sortases are key virulence factors in Gram-positive bacteria. These enzymes embed surface proteins in the cell wall through a transpeptidation reaction that involves recognizing a penta-peptide "sorting signal" in a target protein, cleaving it, and covalently attaching it to a second substrate that is later inserted into the cell wall. Although well studied, several aspects of the mechanism by which sortases perform these functions remains unclear. In particular, experiments have revealed two potential sorting signal binding motifs: a "Threonine-Out" (Thr-Out) structure in which the catalytically critical threonine residues protrudes into solution, and a "Threonine-In" (Thr-In) configuration in which this residue inserts into the binding site. To determine which of these is the biologically relevant state, we have performed a series of conventional and hybrid quantum mechanics/molecular mechanics (QM/MM) molecular dynamics simulations of the Staphylococcus aureus sortase A (SrtA) enzyme bound to a sorting signal substrate. Through the use of multi-dimensional metadynamics, our simulations were able to both map the acylation mechanism of SrtA in the Thr-In and Thr-Out states, as well as determine the free energy minima and barriers along these reactions. Results indicate that in both states the catalytic mechanisms are similar, however the free energy barriers are lower in the Thr-In configuration, suggesting that Thr-In is the catalytically relevant state. This has important implications for advancing our understanding of the mechanisms of sortase enzymes, as well we for future structure based drug design efforts aimed at inhibiting sortase function in vivo.
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Affiliation(s)
- Pooja Shrestha
- Department of Physics and Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, 3440 S Dearborn St., Chicago, IL 60616, USA
| | - Jeff Wereszczynski
- Department of Physics and Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, 3440 S Dearborn St., Chicago, IL 60616, USA.
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Taranova M, Hirsh AD, Perkins NC, Andricioaei I. Role of microscopic flexibility in tightly curved DNA. J Phys Chem B 2014; 118:11028-36. [PMID: 25155114 PMCID: PMC4174995 DOI: 10.1021/jp502233u] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
The
genetic material in living cells is organized into complex
structures in which DNA is subjected to substantial contortions. Here
we investigate the difference in structure, dynamics, and flexibility
between two topological states of a short (107 base pair) DNA sequence
in a linear form and a covalently closed, tightly curved circular
DNA form. By employing a combination of all-atom molecular dynamics
(MD) simulations and elastic rod modeling of DNA, which allows capturing
microscopic details while monitoring the global dynamics, we demonstrate
that in the highly curved regime the microscopic flexibility of the
DNA drastically increases due to the local mobility of the duplex.
By analyzing vibrational entropy and Lipari–Szabo NMR order
parameters from the simulation data, we propose a novel model for
the thermodynamic stability of high-curvature DNA states based on
vibrational untightening of the duplex. This novel view of DNA bending
provides a fundamental explanation that bridges the gap between classical
models of DNA and experimental studies on DNA cyclization, which so
far have been in substantial disagreement.
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Affiliation(s)
- Maryna Taranova
- Department of Chemistry, University of California , 1102 Natural Sciences 2, Irvine, California 92697, United States
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Park SH, Jung SH, Ahn J, Lee JH, Kwon KY, Jeon J, Kim H, Jaworski J, Jung JH. Reversibly tunable helix inversion in supramolecular gels trigged by Co2+. Chem Commun (Camb) 2014; 50:13495-8. [DOI: 10.1039/c4cc05699j] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Li LY, Jia HN, Yu HJ, Du KJ, Lin QT, Qiu KQ, Chao H, Ji LN. Synthesis, characterization, and DNA-binding studies of ruthenium complexes [Ru(tpy)(ptn)]2+ and Ru(dmtpy)(ptn)]2+. J Inorg Biochem 2012; 113:31-9. [PMID: 22687492 DOI: 10.1016/j.jinorgbio.2012.03.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 03/15/2012] [Accepted: 03/21/2012] [Indexed: 11/24/2022]
Abstract
Two ruthenium(II) polypyridyl complexes [Ru(tpy)(ptn)](2+) (1) and Ru(dmtpy)(ptn)](2+) (2) (ptn=3-(1,10-phenanthrolin-2-yl)-as-triazino[5,6-f]naphthalene, tpy=2,2':6',2"-terpyridine, dmtpy=5,5'-dimethyl-2,2':6',2"-terpyridine) have been synthesized and characterized by elemental analysis, (1)H NMR, mass spectrometry and crystal structure analysis. Spectroscopic studies together with isothermal titration calorimetry (ITC) and viscosity measurements prove that two complexes bind to DNA in an intercalative mode. ITC experiments show that the binding mode for complex 2 is entropically driven, while an entropy-driven initial binding of complex 1 is followed by an entropically and enthalpically favorable process. This difference may be attributed to the ancillary ligand effects on the DNA binding of Ru(II) complexes. Circular dichroism titrations of calf thymus DNA (CT-DNA) with Ru(II) complexes show that complexes 1 and 2 induce B to Z conformational transition of calf thymus DNA at low ionic strength (0.05 M NaCl). The induced Z-DNA conformation can revert to B form when Ru(II) complexes are displaced by ethidium bromide or at high ionic strengths ([NaCl]=0.4 M), but keeps intact with temperature ranged from 25 to 90 °C. The unique structure and characteristics of Ru(II) complexes designed in this investigation will be useful for the study of Z-DNA.
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Affiliation(s)
- Lü-Ying Li
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China
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Carra C, Cucinotta FA. Accurate prediction of the binding free energy and analysis of the mechanism of the interaction of replication protein A (RPA) with ssDNA. J Mol Model 2011; 18:2761-83. [PMID: 22116609 DOI: 10.1007/s00894-011-1288-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 10/19/2011] [Indexed: 10/15/2022]
Abstract
The eukaryotic replication protein A (RPA) has several pivotal functions in the cell metabolism, such as chromosomal replication, prevention of hairpin formation, DNA repair and recombination, and signaling after DNA damage. Moreover, RPA seems to have a crucial role in organizing the sequential assembly of DNA processing proteins along single stranded DNA (ssDNA). The strong RPA affinity for ssDNA, K(A) between 10(-9)-10(-10) M, is characterized by a low cooperativity with minor variation for changes on the nucleotide sequence. Recently, new data on RPA interactions was reported, including the binding free energy of the complex RPA70AB with dC(8) and dC(5), which has been estimated to be -10 ± 0.4 kcal mol(-1) and -7 ± 1 kcal mol(-1), respectively. In view of these results we performed a study based on molecular dynamics aimed to reproduce the absolute binding free energy of RPA70AB with the dC(5) and dC(8) oligonucleotides. We used several tools to analyze the binding free energy, rigidity, and time evolution of the complex. The results obtained by MM-PBSA method, with the use of ligand free geometry as a reference for the receptor in the separate trajectory approach, are in excellent agreement with the experimental data, with ±4 kcal mol(-1) error. This result shows that the MM-PB(GB)SA methods can provide accurate quantitative estimates of the binding free energy for interacting complexes when appropriate geometries are used for the receptor, ligand and complex. The decomposition of the MM-GBSA energy for each residue in the receptor allowed us to correlate the change of the affinity of the mutated protein with the ΔG(gas+sol) contribution of the residue considered in the mutation. The agreement with experiment is optimal and a strong change in the binding free energy can be considered as the dominant factor in the loss for the binding affinity resulting from mutation.
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Affiliation(s)
- Claudio Carra
- Universities Space Research Association, Houston, TX 77058, USA.
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