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Berbeć S, Dec R, Molodenskiy D, Wielgus-Kutrowska B, Johannessen C, Hernik-Magoń A, Tobias F, Bzowska A, Ścibisz G, Keiderling TA, Svergun D, Dzwolak W. β2-Type Amyloidlike Fibrils of Poly-l-glutamic Acid Convert into Long, Highly Ordered Helices upon Dissolution in Dimethyl Sulfoxide. J Phys Chem B 2018; 122:11895-11905. [DOI: 10.1021/acs.jpcb.8b08308] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Sylwia Berbeć
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 1 Pasteur Street, 02-093 Warsaw, Poland
| | - Robert Dec
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 1 Pasteur Street, 02-093 Warsaw, Poland
| | - Dmitry Molodenskiy
- European Molecular Biology Laboratory, Hamburg Outstation, c/o DESY, Hamburg 22607, Germany
| | - Beata Wielgus-Kutrowska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw 02-093, Poland
| | | | - Agnieszka Hernik-Magoń
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 1 Pasteur Street, 02-093 Warsaw, Poland
| | - Fernando Tobias
- Department of Chemistry, University of Illinois at Chicago, Chicago 60607-7061, United States
| | - Agnieszka Bzowska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw 02-093, Poland
| | - Grzegorz Ścibisz
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 1 Pasteur Street, 02-093 Warsaw, Poland
| | - Timothy A. Keiderling
- Department of Chemistry, University of Illinois at Chicago, Chicago 60607-7061, United States
| | - Dmitri Svergun
- European Molecular Biology Laboratory, Hamburg Outstation, c/o DESY, Hamburg 22607, Germany
| | - Wojciech Dzwolak
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 1 Pasteur Street, 02-093 Warsaw, Poland
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2
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Elenewski JE, Velizhanin KA, Zwolak M. A spin-1 representation for dual-funnel energy landscapes. J Chem Phys 2018; 149:035101. [PMID: 30037251 PMCID: PMC7723752 DOI: 10.1063/1.5036677] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The interconversion between the left- and right-handed helical folds of a polypeptide defines a dual-funneled free energy landscape. In this context, the funnel minima are connected through a continuum of unfolded conformations, evocative of the classical helix-coil transition. Physical intuition and recent conjectures suggest that this landscape can be mapped by assigning a left- or right-handed helical state to each residue. We explore this possibility using all-atom replica exchange molecular dynamics and an Ising-like model, demonstrating that the energy landscape architecture is at odds with a two-state picture. A three-state model-left, right, and unstructured-can account for most key intermediates during chiral interconversion. Competing folds and excited conformational states still impose limitations on the scope of this approach. However, the improvement is stark: Moving from a two-state to a three-state model decreases the fit error from 1.6 kBT to 0.3 kBT along the left-to-right interconversion pathway.
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Affiliation(s)
- Justin E. Elenewski
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- Maryland Nanocenter, University of Maryland, College Park, MD 20742, USA
| | | | - Michael Zwolak
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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3
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Grubišić S, Chandramouli B, Barone V, Brancato G. Chain length, temperature and solvent effects on the structural properties of α-aminoisobutyric acid homooligopeptides. Phys Chem Chem Phys 2018; 18:20389-98. [PMID: 27402118 DOI: 10.1039/c6cp01120a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Non-coded α-amino acids, originally exploited by nature, have been successfully reproduced by recent synthetic strategies to confer special structural and functional properties to small peptides. The most known and well-studied atypical residue is α-aminoisobutyric acid (Aib), which is contained in a fairly large number of peptides with known antibiotic effects. Here, we report on a molecular dynamics (MD) study of a series of homooligopeptides based on α-aminoisobutyric acid (Aib) with increasing length (Ac-(Aib)n-NMe, n = 5, 6, 7 and 10) and at various temperatures, employing a recent extension of the AMBER force field tailored for the Aib residue. Solvent effects have been analyzed by comparative MD simulations of a heptapeptide in water and dimethylsulfoxide at different temperatures. Our results show that the preference for the 310- and/or α-helix structures, which typically characterize Aib based peptides, is finely tuned by several factors including the chain length, temperature and solvent nature. While the transitions between intra-molecular i → i + 3 and i → i + 4 hydrogen bonds characterizing 310 and α-helices, respectively, are rather fast in small peptides (in the picosecond timescale), our analysis shows that the above physical and chemical factors modulate the relative equilibrium populations of the two helical structures. The obtained results nicely agree with available experimental data and support the use of the new force field for modeling Aib containing peptides.
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Affiliation(s)
- Sonja Grubišić
- Center for Chemistry, IHTM, University of Belgrade, Njegoševa 12, P.O. Box 815, 11001 Belgrade, Serbia.
| | - Balasubramanian Chandramouli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy. and Istituto Nazionale di Fisica Nucleare, Largo Pontecorvo 3, I-56100 Pisa, Italy
| | - Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy. and Istituto Nazionale di Fisica Nucleare, Largo Pontecorvo 3, I-56100 Pisa, Italy
| | - Giuseppe Brancato
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy. and Istituto Nazionale di Fisica Nucleare, Largo Pontecorvo 3, I-56100 Pisa, Italy
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4
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Saini A, Sharma S, Jaswal RR. Non-covalent Interactions Guide the Structural Plasticity of Desmin Tubulin Binding Peptides: A Molecular Mechanics and Molecular Dynamics Study. Int J Pept Res Ther 2015. [DOI: 10.1007/s10989-015-9474-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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5
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Li J, Lakshminarayanan R, Bai Y, Liu S, Zhou L, Pervushin K, Verma C, Beuerman RW. Molecular dynamics simulations of a new branched antimicrobial peptide: a comparison of force fields. J Chem Phys 2013; 137:215101. [PMID: 23231260 DOI: 10.1063/1.4768899] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Branched antimicrobial peptides are promising as a new class of antibiotics displaying high activity and low toxicity and appear to work through a unique mechanism of action. We explore the structural dynamics of a covalently branched 18 amino acid peptide (referred to as B2088) in aqueous and membrane mimicking environments through molecular dynamics (MD) simulations. Towards this, we carry out conventional MD simulations and supplement these with replica exchange simulations. The simulations are carried out using four different force fields that are commonly employed for simulating biomolecular systems. These force fields are GROMOS53a6, CHARMM27 with cMAP, CHARMM27 without cMAP and AMBER99sb. The force fields are benchmarked against experimental data available from circular dichroism and nuclear magnetic resonance spectroscopies, and show that CHARMM27 without cMAP correction is the most successful in reproducing the structural dynamics of B2088 both in water and in the presence of micelles. Although the four force fields predict different structures of B2088, they all show that B2088 stabilizes against the head group of the lipid through hydrogen bonding of its Lys and Arg side chains. This leads us to hypothesize that B2088 is unlikely to penetrate into the hydrophobic region of the membrane owing to the high free energy costs of transfer from water, and possibly acts by carpeting and thus disrupting the membrane.
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Affiliation(s)
- Jianguo Li
- Singapore Eye Research Institute, 11 Third Hospital Avenue, #06-00, Singapore 168751.
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6
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Grubišić S, Brancato G, Barone V. An improved AMBER force field for α,α-dialkylated peptides: intrinsic and solvent-induced conformational preferences of model systems. Phys Chem Chem Phys 2013; 15:17395-407. [DOI: 10.1039/c3cp52721b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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7
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Dzwolak W, Kalinowski J, Johannessen C, Babenko V, Zhang G, Keiderling TA. On the DMSO-Dissolved State of Insulin: A Vibrational Spectroscopic Study of Structural Disorder. J Phys Chem B 2012; 116:11863-71. [DOI: 10.1021/jp3062674] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Wojciech Dzwolak
- Department of Chemistry, University of Warsaw, Pasteura 1, 02-093
Warsaw, Poland
| | - Jarosław Kalinowski
- Institute of High
Pressure Physics, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw, Poland
| | - Christian Johannessen
- Manchester Interdisciplinary
Biocentre, University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Viktoria Babenko
- Department of Chemistry, University of Warsaw, Pasteura 1, 02-093
Warsaw, Poland
| | - Ge Zhang
- Department of Chemistry, University of Illinois at Chicago, 845
West Taylor Street (m/c 111), Chicago, Illinois 60607-7061, United
States
| | - Timothy A. Keiderling
- Department of Chemistry, University of Illinois at Chicago, 845
West Taylor Street (m/c 111), Chicago, Illinois 60607-7061, United
States
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8
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Pellegrino S, Contini A, Clerici F, Gori A, Nava D, Gelmi ML. 1H-Azepine-4-amino-4-carboxylic acid: a new α,α-disubstituted ornithine analogue capable of inducing helix conformations in short Ala-Aib pentapeptides. Chemistry 2012; 18:8705-15. [PMID: 22689465 DOI: 10.1002/chem.201104023] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 03/30/2012] [Indexed: 11/08/2022]
Abstract
A very efficient synthesis of orthogonally protected 1H-azepine-4-amino-4-carboxylic acid, abbreviated as Azn, a conformationally restricted analogue of ornithine, was realized. It was obtained on a gram scale in good overall yield in five steps, three of which did not require isolation of the intermediates, starting from the readily available 1-amino-4-oxo-cyclohexane-4-carboxylic acid. Both enantiomers were used for the preparation of pentapeptide models containing Ala, Aib, and Azn. Conformational studies using both spectroscopic techniques (NMR, CD) and molecular dynamics on model 5-mer peptides showed that the (R)-Azn isomer possesses a marked helicogenic effect.
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Affiliation(s)
- Sara Pellegrino
- DISMAB, Sezione di Chimica Organica A. Marchesini, Facoltà di Farmacia, Università degli Studi Milano, Via Venezian 21, 20133 Milano, Italy.
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9
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Grubišić S, Brancato G, Pedone A, Barone V. Extension of the AMBER force field to cyclic α,α dialkylated peptides. Phys Chem Chem Phys 2012; 14:15308-20. [DOI: 10.1039/c2cp42713c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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10
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Wang D, Friedmann M, Gattin Z, Jaun B, van Gunsteren W. The Propensity of α-Aminoisobutyric Acid (=2-Methylalanine; Aib) to Induce Helical Secondary Structure in an α-Heptapeptide: A Computational Study. Helv Chim Acta 2010. [DOI: 10.1002/hlca.200900420] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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11
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Meier K, Gunsteren WFV. Cyclic β-Helical/β-Hairpin d,l-α-Peptide: Study of Its Folding Properties and Structure Refinement Using Molecular Dynamics. J Phys Chem A 2010; 114:1852-9. [DOI: 10.1021/jp906218f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Katharina Meier
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, Zürich ETH, 8093 Zürich, Switzerland
| | - Wilfred F. van Gunsteren
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, Zürich ETH, 8093 Zürich, Switzerland
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12
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Maekawa H, Ge NH. Comparative Study of Electrostatic Models for the Amide-I and -II Modes: Linear and Two-Dimensional Infrared Spectra. J Phys Chem B 2010; 114:1434-46. [DOI: 10.1021/jp908695g] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hiroaki Maekawa
- Department of Chemistry, University of California at Irvine, Irvine, California 92697-2025
| | - Nien-Hui Ge
- Department of Chemistry, University of California at Irvine, Irvine, California 92697-2025
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13
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Rajapandian V, Raman SS, Hakkim V, Parthasarathi R, Subramanian V. Molecular mechanics and molecular dynamics study on azurin using extensible and systematic force field (ESFF). ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.theochem.2009.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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14
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Banerjee R, Chattopadhyay S, Basu G. Conformational preferences of a short Aib/Ala-based water-soluble peptide as a function of temperature. Proteins 2009; 76:184-200. [PMID: 19137603 DOI: 10.1002/prot.22337] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The amino acid Aib predisposes a peptide to be helical with context-dependent preference for either 3(10)- or alpha- or a mixed helical conformation. Short peptides also show an inherent tendency to be unfolded. To characterize helical and unfolded states adopted by water-soluble Aib-containing peptides, the conformational preference of Ac-Ala-Aib-Ala-Lys-Ala-Aib-Lys-Ala-Lys-Ala-Aib-Tyr-NH(2) was determined by CD, NMR and MD simulations as a function of temperature. Temperature-dependent CD data indicated the contribution of two major components, each an admixture of helical and extended/polyproline II structures. Both right- and left-handed helical conformations were detected from deconvolution of CD data and (13)C NMR experiments. The presence of a helical backbone, more pronounced at the N-terminal, and a temperature-induced shift in alpha-helix/3(10)-helix equilibrium, more pronounced at the C-terminal, emerged from NMR data. Starting from polyproline II, the N-terminal of the peptide folded into a helical backbone in MD simulations within 5 ns at 60 degrees C. Longer simulations showed a mixed-helical backbone to be stable over the entire peptide at 5 degrees C while at 60 degrees C the mixed-helix was either stable at the N-terminus or occurred in short stretches through out the peptide, along with a significant population of polyproline II. Our results point towards conformational heterogeneity of water-soluble Aib-based peptide helices and the associated subtleties. The problem of analyzing CD and NMR data of both left- and right-handed helices are discussed, especially the validity of the ellipticity ratio [theta](222)/[theta](207), as a reporter of alpha-/3(10)- population ratio, in right- and left-handed helical mixtures.
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Affiliation(s)
- Raja Banerjee
- Department of Biotechnology, West Bengal University of Technology, Kolkata 700064, India.
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15
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Raman SS, Vijayaraj R, Parthasarathi R, Subramanian V. Helix forming tendency of valine substituted poly-alanine: a molecular dynamics investigation. J Phys Chem B 2008; 112:9100-4. [PMID: 18597521 DOI: 10.1021/jp7119813] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In this study, classical molecular dynamics simulations have been carried out on the valine (guest) substituted poly alanine (host) using the host-guest peptide approach to understand the role of valine in the formation and stabilization of helix. Valine has been substituted in the host peptide starting from N terminal to C terminal. Various structural parameters have been obtained from the molecular dynamics simulation to understand the tolerance of helical motif to valine. Depending on the position of valine in the host peptide, it stabilizes (or destabilizes) the formation of the helical structure. The substitution of valine in the poly alanine at some positions has no effect on the helix formation (deformation). It is interesting to observe the coexistence of 3 10 and alpha-helix in the peptides due to the dynamical nature of the hydrogen bonding interaction and sterical interactions.
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Affiliation(s)
- S Sundar Raman
- Chemical Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020 India
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16
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Duarte AMS, van Mierlo CPM, Hemminga MA. Molecular Dynamics Study of the Solvation of an α-Helical Transmembrane Peptide by DMSO. J Phys Chem B 2008; 112:8664-71. [DOI: 10.1021/jp076678j] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Afonso M. S. Duarte
- Laboratory of Biophysics and Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
| | - Carlo P. M. van Mierlo
- Laboratory of Biophysics and Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
| | - Marcus A. Hemminga
- Laboratory of Biophysics and Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
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17
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Schweitzer-Stenner R, Gonzales W, Bourne GT, Feng JA, Marshall GR. Conformational Manifold of α-Aminoisobutyric Acid (Aib) Containing Alanine-Based Tripeptides in Aqueous Solution Explored by Vibrational Spectroscopy, Electronic Circular Dichroism Spectroscopy, and Molecular Dynamics Simulations. J Am Chem Soc 2007; 129:13095-109. [PMID: 17918837 DOI: 10.1021/ja0738430] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Reinhard Schweitzer-Stenner
- Contribution from the Department of Chemistry, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104 and Department of Biochemistry and Molecular Biophysics, Washington University, St. Louis, Missouri 63110
| | - Widalys Gonzales
- Contribution from the Department of Chemistry, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104 and Department of Biochemistry and Molecular Biophysics, Washington University, St. Louis, Missouri 63110
| | - Gregory T. Bourne
- Contribution from the Department of Chemistry, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104 and Department of Biochemistry and Molecular Biophysics, Washington University, St. Louis, Missouri 63110
| | - Jianwen A. Feng
- Contribution from the Department of Chemistry, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104 and Department of Biochemistry and Molecular Biophysics, Washington University, St. Louis, Missouri 63110
| | - Garland R. Marshall
- Contribution from the Department of Chemistry, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104 and Department of Biochemistry and Molecular Biophysics, Washington University, St. Louis, Missouri 63110
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18
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van Gunsteren WF, Bakowies D, Baron R, Chandrasekhar I, Christen M, Daura X, Gee P, Geerke DP, Glättli A, Hünenberger PH, Kastenholz MA, Oostenbrink C, Schenk M, Trzesniak D, van der Vegt NFA, Yu HB. Biomolecular modeling: Goals, problems, perspectives. Angew Chem Int Ed Engl 2007; 45:4064-92. [PMID: 16761306 DOI: 10.1002/anie.200502655] [Citation(s) in RCA: 408] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Computation based on molecular models is playing an increasingly important role in biology, biological chemistry, and biophysics. Since only a very limited number of properties of biomolecular systems is actually accessible to measurement by experimental means, computer simulation can complement experiment by providing not only averages, but also distributions and time series of any definable quantity, for example, conformational distributions or interactions between parts of systems. Present day biomolecular modeling is limited in its application by four main problems: 1) the force-field problem, 2) the search (sampling) problem, 3) the ensemble (sampling) problem, and 4) the experimental problem. These four problems are discussed and illustrated by practical examples. Perspectives are also outlined for pushing forward the limitations of biomolecular modeling.
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Affiliation(s)
- Wilfred F van Gunsteren
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH, 8093 Zurich, Switzerland.
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19
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van Gunsteren WF, Bakowies D, Baron R, Chandrasekhar I, Christen M, Daura X, Gee P, Geerke DP, Glättli A, Hünenberger PH, Kastenholz MA, Oostenbrink C, Schenk M, Trzesniak D, van der Vegt NFA, Yu HB. Biomolekulare Modellierung: Ziele, Probleme, Perspektiven. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200502655] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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20
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21
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Carstens H, Renner C, Milbradt AG, Moroder L, Tavan P. Multiple Loop Conformations of Peptides Predicted by Molecular Dynamics Simulations Are Compatible with Nuclear Magnetic Resonance†. Biochemistry 2005; 44:4829-40. [PMID: 15779909 DOI: 10.1021/bi047453r] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The affinity and selectivity of protein-protein interactions can be fine-tuned by varying the size, flexibility, and amino acid composition of involved surface loops. As a model for such surface loops, we study the conformational landscape of an octapeptide, whose flexibility is chemically steered by a covalent ring closure integrating an azobenzene dye into and by a disulfide bridge additionally constraining the peptide backbone. Because the covalently integrated azobenzene dyes can be switched by light between a bent cis state and an elongated trans state, six cyclic peptide models of strongly different flexibilities are obtained. The conformational states of these peptide models are sampled by NMR and by unconstrained molecular dynamics (MD) simulations. Prototypical conformations and the free-energy landscapes in the high-dimensional space spanned by the phi/psi angles at the peptide backbone are obtained by clustering techniques from the MD trajectories. Multiple open-loop conformations are shown to be predicted by MD particularly in the very flexible cases and are shown to comply with the NMR data despite the fact that such open-loop conformations are missing in the refined NMR structures.
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Affiliation(s)
- Heiko Carstens
- Lehrstuhl für BioMolekulare Optik, Oettingenstrasse 67, Ludwig-Maximilians-Universität München, 80538 München, Germany
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22
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Kubasik M, Kotz J, Szabo C, Furlong T, Stace J. Helix-helix interconversion rates of short13C-labeled helical peptides as measured by dynamic NMR spectroscopy. Biopolymers 2005; 78:87-95. [PMID: 15657893 DOI: 10.1002/bip.20235] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The rates at which a peptide hexamer and a peptide octamer interconvert between left- and right-handed helical forms in CD2Cl2 solution have been characterized by 13C dynamic NMR (DNMR) spectroscopy. The peptide esters studied are Fmoc-(Aib)n-OtBu (n = 6 and 8), where Fmoc is 9-fluorenylmethyoxycarbonyl and Aib is the strongly helix-forming residue alpha-aminoisobutyric acid. Because the Aib residue is itself achiral, homooligomers of this residue form a 50/50 mixture of enantiomeric 3(10)-helices in solution. It has been demonstrated (R.-P. Hummel, C. Toniolo, and G. Jung, Angewandte Chemie International Edition, 1987, Vol. 26, pp. 1150-1152) that oligomers of Aib interconvert on the millisecond timescale. We have performed lineshape analysis of 13C-NMR spectra collected for our peptides enriched with 13C at a single residue. Rate constants for the octamer range from 6 s(-1) at 196 K to about 56,500 s(-1) at 320 K. At all temperatures, the hexamer interconverts about three times faster than the octamer. Eyring plots of the data reveal experimentally indistinguishable DeltaH++ values for the hexamer and octamer of 37.8 +/- 0.6 and 37.6 +/- 0.4 kJ mol(-1) respectively. The difference in the rates of interconversion is dictated by entropic factors. The hexamer and octamer exhibit negative DeltaS++ values of -29.0(-1) +/- 2.5 and -37.3 +/- 1.7 J K(-1) mol(-1), respectively. A mechanism for the helix-helix interconversion is proposed. and calculated DeltaG++ values are compared to the estimate for a decamer undergoing a helix-helix interconversion.
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Affiliation(s)
- Matthew Kubasik
- Department of Chemistry, Fairfield University, Fairfield, CT 06824, USA.
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23
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Glättli A, van Gunsteren WF. Are NMR-Derived Model Structures for β-Peptides Representative for the Ensemble of Structures Adopted in Solution? Angew Chem Int Ed Engl 2004. [DOI: 10.1002/ange.200460384] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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24
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Glättli A, van Gunsteren WF. Are NMR-Derived Model Structures for β-Peptides Representative for the Ensemble of Structures Adopted in Solution? Angew Chem Int Ed Engl 2004; 43:6312-6. [PMID: 15523681 DOI: 10.1002/anie.200460384] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Alice Glättli
- Laboratorium für Physikalische Chemie, ETH, ETH Hönggerberg, HCI, 8093 Zürich, Switzerland
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25
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Glättli A, Seebach D, van Gunsteren W. Do Valine Side Chains Have an Influence on the Folding Behavior ofβ-Substitutedβ-Peptides? Helv Chim Acta 2004. [DOI: 10.1002/hlca.200490223] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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26
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Soares T, Christen M, Hu K, van Gunsteren WF. Alpha- and beta-polypeptides show a different stability of helical secondary structure. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.06.062] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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27
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Abstract
The growth factor receptor-bound protein 2 (Grb2) plays an important role in the Ras signaling pathway. Several proteins were found to be overexpressed by oncogenes in the Ras signaling pathway, rendering Grb2 a potential target for the design of antitumor agents. Blocking the interaction between the phosphotyrosine-containing activated receptor and the Src-homology 2 (SH2) domain of Grb2 thus constitutes an important strategy for the development of potential anticancer agents. X-ray, NMR structural investigations, and molecular modeling studies have provided the target structure of Grb2 SH2 domain-alone or complexed with a phosphotyrosine-containing peptide-which is useful for the structure-based design of peptides or peptidomimetics with high affinity for the Grb2 SH2 domain. We review here the variety of approaches to Grb2 SH2 pepide inhibitors developed with the aim of interrupting Grb2 recognition. Inhibitory effects of peptide analogs on the Grb2 SH2 domain and their binding affinities for Grb2 SH2 were determined by ELISA, cell-based assays, or Surface Plasman Resonance (SPR) technology. Results of theses studies provide important information for further modifications of lead peptides, and should lead to the discovery of potent peptides as anticancer agents.
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Affiliation(s)
- Feng-Di T Lung
- Department of Nutrition, China Medical College 91, Hsueh-Shih Road, Taichung 404, Taiwan, Republic of China.
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28
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Yu H, Daura X, van Gunsteren WF. Molecular dynamics simulations of peptides containing an unnatural amino acid: dimerization, folding, and protein binding. Proteins 2004; 54:116-27. [PMID: 14705028 DOI: 10.1002/prot.10502] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We have performed molecular dynamics (MD) simulations to study the dimerization, folding, and binding to a protein of peptides containing an unnatural amino acid. NMR studies have shown that the substitution of one residue in a tripeptide beta-strand by the unnatural amino acid Hao (5-HO2CCONH-2-MeO-C6H3-CO-NHNH2) modifies the conformational flexibility of the beta-strand and the hydrogen-bonding properties of its two edges: The number of hydrogen-bond donors and acceptors increases at one edge, whereas at the other, they are sterically hindered. In simulations in chloroform, the Hao-containing peptide 9 (i-PrCO-Phe-Hao-Val-NHBu) forms a beta-sheet-like hydrogen-bonded dimer, in good agreement with the available experimental data. Addition of methanol to the solution induces instability of this beta-sheet, as confirmed by the experiments. MD simulations also reproduce the folding of the synthetic peptide 1a (i-PrCO-Hao-Ut-Phe-Ile-Leu-NHMe) into a beta-hairpin-like structure in chloroform. Finally, the Hao-containing peptide, Ac-Ala-Hao-Ala-NHMe, is shown to form a stable complex with the Ras analogue, Rap1 A, in water at room temperature. Together with the available experimental data, these simulation studies indicate that Hao-containing peptides may serve as inhibitors of beta-sheet interactions between proteins.
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Affiliation(s)
- Haibo Yu
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology Zurich, ETH Hönggerberg, 8093 Zürich, Switzerland
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29
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Hydrogen Bonds in GlcNAc( β1,3)Gal( β)OMe in DMSO Studied by NMR Spectroscopy and Molecular Dynamics Simulations. B KOREAN CHEM SOC 2004. [DOI: 10.5012/bkcs.2004.25.2.198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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30
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Daura X, Glättli A, Gee P, Peter C, van Gunsteren WF. Unfolded state of peptides. ADVANCES IN PROTEIN CHEMISTRY 2004; 62:341-60. [PMID: 12418109 DOI: 10.1016/s0065-3233(02)62013-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Xavier Daura
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology Zurich, ETH Hönggerberg, CH-8093 Zurich
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31
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Metwally E, Ismail HA, Davison JS, Mathison R. A tree-based algorithm for determining the effects of solvation on the structure of salivary gland tripeptide NH3+-D-PHE-D-GLU-GLY-COO-. Biophys J 2003; 85:1503-11. [PMID: 12944268 PMCID: PMC1303327 DOI: 10.1016/s0006-3495(03)74583-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A D-enantiomeric analog of the submandibular gland rat-1 tripeptide FEG (Seq: NH(3)(+)-Phe-Glu-Gly-COO(-)) called feG (Seq: NH(3)(+)-D-Phe-D-Glu-Gly-COO(-)) was examined by molecular dynamics simulations in water. Previous in vacuo simulations suggested a conformation consisting predominantly of interactions between the Phe side chain and glutamyl-carboxyl group and a carboxyl/amino termini interaction. The solvated peptide was simulated using two approaches which were compared-a single 400-ns simulation and a "simulation tree." The "tree" approach utilized 45 10-ns simulations with different conformations used as initial structures for given trajectories. We demonstrate that multiple short duration simulations are able to describe the same conformational space as that described by longer simulations. Furthermore, previously described in vacuo interactions were confirmed with amendments: the previously described head-to-tail arrangement of the amino and carboxyl termini, was not observed; the interaction between the glutamyl carboxyl and Phe side chain describes only one of a continuum of conformations present wherein the aromatic residue remains in close proximity to the glutamyl carbonyl group, and also interacts with either of the two available carboxyl groups. Finally, utilizing only two separate 10-ns trajectories, we were able to better describe the conformational space than a single 60-ns trajectory, realizing a threefold decrease in the computational complexity of the problem.
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Affiliation(s)
- Essam Metwally
- Department of Physiology and Biophysics, The University of Calgary, Calgary, Alberta, Canada.
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32
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Bystroff C, Garde S. Helix propensities of short peptides: molecular dynamics versus bioinformatics. Proteins 2003; 50:552-62. [PMID: 12577261 DOI: 10.1002/prot.10252] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Knowledge-based potential functions for protein structure prediction assume that the frequency of occurrence of a given structure or a contact in the protein database is a measure of its free energy. Here, we put this assumption to test by comparing the results obtained from sequence-structure cluster analysis with those obtained from long all-atom molecular dynamics simulations. Sixty-four eight-residue peptide sequences with varying degrees of similarity to the canonical sequence pattern for amphipathic helix were drawn from known protein structures, regardless of whether they were helical in the protein. Each was simulated using AMBER6.0 for at least 10 ns using explicit waters. The total simulation time was 1176 ns. The resulting trajectories were tested for reproducibility, and the helical content was measured. Natural peptides whose sequences matched the amphipathic helix motif with greater than 50% confidence were significantly more likely to form helix during the course of the simulation than peptides with lower confidence scores. The sequence pattern derived from the simulation data closely resembles the motif pattern derived from the database cluster analysis. The difficulties encountered in sampling conformational space and sequence space simultaneously are discussed.
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33
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Baell JB, Huang DCS. Prospects for targeting the Bcl-2 family of proteins to develop novel cytotoxic drugs. Biochem Pharmacol 2002; 64:851-63. [PMID: 12213579 DOI: 10.1016/s0006-2952(02)01148-6] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Over the last decade the molecular mechanisms controlling programmed cell death (apoptosis) have become clearer. It appears that many physiological and damage signals activate the cell death machinery by inhibiting the pro-survival Bcl-2 proteins. Since many chemotherapeutic drugs used to treat cancers activate the cell death machinery indirectly, there is much interest in developing peptide and non-peptide mimics of the BH3-only proteins, a family of proteins that act as direct antagonists of Bcl-2, as novel anti-cancer agents. This commentary review current progress in our search for such drugs and discusses recent findings in light of our current understanding of the cell death signaling. The potential for discovering novel agents that may form a useful part of the treatment of malignant disease is enormous but we still lack critical understanding of precisely how Bcl-2 function. However, the frequency of mutations affecting proteins that (directly or indirectly) impinge on apoptosis suggests that the approach of targeting Bcl-2 might be a profitable one.
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Affiliation(s)
- Jonathan B Baell
- Molecular Genetics of Cancer Division, The Walter and Eliza Hall Institute of Medical Research, Post Office Royal Melbourne Hospital, Parkville, Vic. 3050, Australia
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34
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Affiliation(s)
- Wilfred F. Van Gunsteren
- Laboratory of Physical Chemistry Swiss Federal Institute of Technology Zurich ETH Hönggerberg, 8093 Zurich (Switzerland)
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35
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36
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Bellanda M, Peggion E, Bürgi R, van Gunsteren W, Mammi S. Conformational study of an Aib-rich peptide in DMSO by NMR. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2001; 57:97-106. [PMID: 11168893 DOI: 10.1034/j.1399-3011.2001.00794.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The strong propensity of 2-amino-2-methyl propanoic acid (Aib)-rich peptides to form stable helical structures is well documented. NMR analysis of the short peptide Z-(Aib)5-L-Leu-(Aib)2-OMe indicates the presence of a well-characterized 3(10)-helix even in dimethylsulfoxide (DMSO), a solvent known to disrupt helical structures. The structure remains stable at least up to 348 K. Stereospecific assignment of the diastereotopic methyls of Aib was achieved, with the assumption of a specific helical screw sense. The methyl more eclipsed with respect to the CO vector resonates at a higher field in the carbon dimension. Molecular dynamics simulations successfully predict the 3J(CHNH) coupling constant of Leu6 and most of the H-bonding pattern. Discrepancies were found for Aib3 and Aib7 amide protons which can be explained by a higher sensitivity of the simulations to the helix fraying at the end of the peptide and by the presence of extended conformations for Leu6 during most of the simulations.
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Affiliation(s)
- M Bellanda
- University of Padova, Department of Organic Chemistry, Biopolymer Research Center, Italy
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