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Yang S, Zhao C, Yang Y, Ren J, Ling S. The Fractal Network Structure of Silk Fibroin Molecules and Its Effect on Spinning of Silkworm Silk. ACS NANO 2023; 17:7662-7673. [PMID: 37042465 DOI: 10.1021/acsnano.3c00105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Animal silk is usually considered to exist as a solid fiber with a highly ordered structure, formed by the hierarchical assembly starting from a single silk fibroin (SF) chain. However, this study showed that silk protein molecules existed in the form of a fractal network structure in aqueous solution, rather than as a single chain. This type of network was relatively rigid with low fractal dimension. Finite element analysis revealed that this network structure significantly helped in the stable storage of SF prior to the spinning process and in the rapid formation of a β-sheeted nanocrystalline and nematic texture during spinning. Further, the strong but brittle mechanical properties of Bombyx mori silk could also be well-explained through the fractal network model of silk fibroin. The strength was mainly derived from the dual network structure, consisting of nodes and β-sheet cross-links, whereas the brittleness could be attributed to the rigidity of the SF chains between these nodes and cross-links. In summary, this study presents insights from network topology for understanding the spinning process of natural silk and the structure-property relationship in silk materials.
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Affiliation(s)
- Shuo Yang
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, China
| | - Chenxi Zhao
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, China
| | - Yunhao Yang
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, China
| | - Jing Ren
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, China
| | - Shengjie Ling
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, China
- Shanghai Clinical Research and Trial Center, Shanghai 201210, People's Republic of China
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2
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Eliaz D, Paul S, Benyamin D, Cernescu A, Cohen SR, Rosenhek-Goldian I, Brookstein O, Miali ME, Solomonov A, Greenblatt M, Levy Y, Raviv U, Barth A, Shimanovich U. Micro and nano-scale compartments guide the structural transition of silk protein monomers into silk fibers. Nat Commun 2022; 13:7856. [PMID: 36543800 PMCID: PMC9772184 DOI: 10.1038/s41467-022-35505-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022] Open
Abstract
Silk is a unique, remarkably strong biomaterial made of simple protein building blocks. To date, no synthetic method has come close to reproducing the properties of natural silk, due to the complexity and insufficient understanding of the mechanism of the silk fiber formation. Here, we use a combination of bulk analytical techniques and nanoscale analytical methods, including nano-infrared spectroscopy coupled with atomic force microscopy, to probe the structural characteristics directly, transitions, and evolution of the associated mechanical properties of silk protein species corresponding to the supramolecular phase states inside the silkworm's silk gland. We found that the key step in silk-fiber production is the formation of nanoscale compartments that guide the structural transition of proteins from their native fold into crystalline β-sheets. Remarkably, this process is reversible. Such reversibility enables the remodeling of the final mechanical characteristics of silk materials. These results open a new route for tailoring silk processing for a wide range of new material formats by controlling the structural transitions and self-assembly of the silk protein's supramolecular phases.
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Affiliation(s)
- D. Eliaz
- grid.13992.300000 0004 0604 7563Department of Molecular Chemistry and Materials Science, Faculty of Chemistry, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - S. Paul
- grid.10548.380000 0004 1936 9377Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691 Stockholm, Sweden
| | - D. Benyamin
- grid.9619.70000 0004 1937 0538Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 9190401 Israel
| | - A. Cernescu
- grid.431971.9Neaspec—Attocube Systems AG, Eglfinger Weg 2, Haar, 85540 Munich Germany
| | - S. R. Cohen
- grid.13992.300000 0004 0604 7563Department of Chemical Research Support, Weizmann Institute of Science, 7610001 Re-hovot, Israel
| | - I. Rosenhek-Goldian
- grid.13992.300000 0004 0604 7563Department of Chemical Research Support, Weizmann Institute of Science, 7610001 Re-hovot, Israel
| | - O. Brookstein
- grid.13992.300000 0004 0604 7563Department of Molecular Chemistry and Materials Science, Faculty of Chemistry, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - M. E. Miali
- grid.13992.300000 0004 0604 7563Department of Molecular Chemistry and Materials Science, Faculty of Chemistry, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - A. Solomonov
- grid.13992.300000 0004 0604 7563Department of Molecular Chemistry and Materials Science, Faculty of Chemistry, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - M. Greenblatt
- grid.13992.300000 0004 0604 7563Department of Chemical and Structural Biology, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Y. Levy
- grid.13992.300000 0004 0604 7563Department of Chemical and Structural Biology, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - U. Raviv
- grid.9619.70000 0004 1937 0538Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 9190401 Israel
| | - A. Barth
- grid.10548.380000 0004 1936 9377Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691 Stockholm, Sweden
| | - U. Shimanovich
- grid.13992.300000 0004 0604 7563Department of Molecular Chemistry and Materials Science, Faculty of Chemistry, Weizmann Institute of Science, 7610001 Rehovot, Israel
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3
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Haskew M, Deacon B, Yong CW, Hardy JG, Murphy ST. Atomistic Simulation of Water Incorporation and Mobility in Bombyx mori Silk Fibroin. ACS OMEGA 2021; 6:35494-35504. [PMID: 34984281 PMCID: PMC8717555 DOI: 10.1021/acsomega.1c05019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
Bombyx mori silk fibroin (SF) is a biopolymer that can be processed into materials with attractive properties (e.g., biocompatibility and degradability) for use in a multitude of technical and medical applications (including textiles, sutures, drug delivery devices, tissue scaffolds, etc.). Utilizing the information from experimental and computational SF studies, a simplified SF model has been produced (alanine-glycine [Ala-Gly] n crystal structure), enabling the application of both molecular dynamic and density functional theory techniques to offer a unique insight into SF-based materials. The secondary structure of the computational model has been evaluated using Ramachandran plots under different environments (e.g., different temperatures and ensembles). In addition, the mean square displacement of water incorporated into the SF model was investigated: the diffusion coefficients, activation energies, most and least favorable positions of water, and trajectory of water diffusion through the SF model are obtained. With further computational study and in combination with experimental data, the behavior/degradation of SF (and similar biomaterials) can be elucidated. Consequently, greater control of the aforementioned technologies may be achieved and positively affect their potential applications.
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Affiliation(s)
- Mathew
John Haskew
- Department
of Engineering, Lancaster University, Bailrigg, Lancaster LA1 4YW, U.K.
- Department
of Chemistry, Lancaster University, Bailrigg, Lancaster LA1 4YB, U.K.
| | - Benjamin Deacon
- Department
of Engineering, Lancaster University, Bailrigg, Lancaster LA1 4YW, U.K.
| | - Chin Weng Yong
- Scientific
Computing Department, Science and Technology Facilities Council, Daresbury Laboratory, Warrington WA4 4AD, U.K.
| | - John George Hardy
- Department
of Chemistry, Lancaster University, Bailrigg, Lancaster LA1 4YB, U.K.
- Materials
Science Institute, Lancaster University, Bailrigg, Lancaster LA1 4YB, U.K.
| | - Samuel Thomas Murphy
- Department
of Engineering, Lancaster University, Bailrigg, Lancaster LA1 4YW, U.K.
- Materials
Science Institute, Lancaster University, Bailrigg, Lancaster LA1 4YB, U.K.
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Structure of Silk I ( Bombyx mori Silk Fibroin before Spinning) -Type II β-Turn, Not α-Helix. Molecules 2021; 26:molecules26123706. [PMID: 34204550 PMCID: PMC8234240 DOI: 10.3390/molecules26123706] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/11/2021] [Accepted: 06/14/2021] [Indexed: 12/04/2022] Open
Abstract
Recently, considerable attention has been paid to Bombyx mori silk fibroin by a range of scientists from polymer chemists to biomaterial researchers because it has excellent physical properties, such as strength, toughness, and biocompatibility. These appealing physical properties originate from the silk fibroin structure, and therefore, structural determinations of silk fibroin before (silk I) and after (silk II) spinning are a key to make wider applications of silk. There are discrepancies about the silk I structural model, i.e., one is type II β-turn structure determined using many solid-state and solution NMR spectroscopies together with selectively stable isotope-labeled model peptides, but another is α-helix or partially α-helix structure speculated using IR and Raman methods. In this review, firstly, the process that led to type II β-turn structure by the authors was introduced in detail. Then the problems in speculating silk I structure by IR and Raman methods were pointed out together with the problem in the assignment of the amide I band in the spectra. It has been emphasized that the conformational analyses of proteins and peptides from IR and Raman studies are not straightforward and should be very careful when the proteins contain β-turn structure using many experimental data by Vass et al. In conclusion, the author emphasized here that silk I structure should be type II β-turn, not α-helix.
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Nishitani N, Hirose T, Matsuda K. Self-assembly of photochromic diarylethene-peptide conjugates stabilized by β-sheet formation at the liquid/graphite interface. Chem Commun (Camb) 2019; 55:5099-5102. [PMID: 30968929 DOI: 10.1039/c9cc02093d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two-dimensional (2-D) self-assembly of diarylethene (DAE)-peptide conjugates at the octanoic acid/graphite interface was investigated by scanning tunnelling microscopy (STM). The open-ring isomer of a DAE-peptide conjugate formed a stable 2-D molecular assembly with an antiparallel β-sheet structure. Quantitative analysis of surface coverage depending on concentration revealed a stronger stabilization effect of the oligopeptide than that of the alkyl group with a similar side chain length.
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Affiliation(s)
- Nobuhiko Nishitani
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
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6
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Wu Y, Kang Z, Tian Z, Wu M, Wang J. Biosynthesis and Characterization of Recombinant Silk-Like Polypeptides Derived from the Heavy Chain of Silk Fibrion. Polymers (Basel) 2017; 9:polym9120669. [PMID: 30965969 PMCID: PMC6418719 DOI: 10.3390/polym9120669] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 11/13/2017] [Accepted: 11/30/2017] [Indexed: 02/03/2023] Open
Abstract
In order to investigate the impacts on the structure and biomedical function of typical fragments derived from repetitive and non-repetitive regions of the Bombyx mori silk fibroin heavy chain, several block combination genes (gs16f1, gs16f4, gs16f8, and gs16f12) were designed, cloned into a fusion protein expression vector tagged with glutathione S-transferase (GST), and expressed in Escherichia coli. Fusion proteins GST-GS16F1, GST-GS16F4, and GST-GS16F8 were purified by GST affinity chromatography, and single bands were identified by SDS-PAGE. Under optimal initial cell density, in ducer concentration and induction expression time, the yield of purified GST-GS16F1, GST-GS16F4, and GST-GS16F8 per liter of bacterial culture reached 79, 53, and 28 mg, respectively. Mass spectrometry revealed molecular weights for GST-GS16F1, GST-GS16F4, and GST-GS16F8 of 37.7, 50.0, and 65.7 kDa, respectively, consistent with the theoretical values of 37.4, 49.4, and 65.5 kDa. Similarly, measured values of pI were 5.35, 4.5, and 4.2 for the fusion proteins, consistent with predicted values of 5.34, 4.44, and 4.09. CD spectra showed the molecular conformation of GS16F1 was mainly β-sheet structure, while more stable α-helix structure formed in GS16F4 and GS16F8.
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7
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Influence factors analysis on the formation of silk I structure. Int J Biol Macromol 2015; 75:398-401. [PMID: 25677178 DOI: 10.1016/j.ijbiomac.2015.02.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 02/02/2015] [Accepted: 02/03/2015] [Indexed: 11/22/2022]
Abstract
Regenerated silk fibroin aqueous solution was used to study the crystalline structure of Bombyx mori silk fibroin in vitro. By controlling environmental conditions and concentration of silk fibroin solution, it provided a means for the direct preparing silk I structure and understanding the details of silk fibroin molecules interactions in formation process. In this study, silk fibroin molecules were assembled to form random coil at low concentration of solution and then, as the concentration increases, were converted to silk I at 55% relative humidity (RH). At the same time, the structure of silk fibroin forming below 45 °C was mostly in silk I. A partial ternary phase diagram of temperature-humidity-concentration was constructed based on the results. The results showed silk I structure could be controlled by adjusting the external environmental conditions. The enhanced control over silk I structure, as embodied in phase diagram, could potentially be utilized to understand the molecular chain conformation of silk I in further research work.
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8
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Carrascoza Mayen JF, Lupan A, Cosar C, Kun AZ, Silaghi-Dumitrescu R. On the roles of the alanine and serine in the β-sheet structure of fibroin. Biophys Chem 2015; 197:10-7. [DOI: 10.1016/j.bpc.2014.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 10/20/2014] [Accepted: 11/09/2014] [Indexed: 11/26/2022]
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9
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The Silk I and Lamella Structures of (Ala-Gly)15 as the Model of Bombyx mori Silk Fibroin Studied with Solid State NMR. BIOTECHNOLOGY OF SILK 2014. [DOI: 10.1007/978-94-007-7119-2_3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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10
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Liang K, Gong Y, Fu J, Yan S, Tan Y, Du R, Xing X, Mo G, Chen Z, Cai Q, Sun D, Wu Z. Microstructural change of degummed Bombyx mori silk: an in situ stretching wide-angle X-ray-scattering study. Int J Biol Macromol 2013; 57:99-104. [PMID: 23466498 DOI: 10.1016/j.ijbiomac.2013.02.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 02/23/2013] [Accepted: 02/25/2013] [Indexed: 11/15/2022]
Abstract
The microstructural change of degummed Bombyx mori silk was examined by in situ wide-angle X-ray-scattering (WAXS) with applied stretching force. WAXS patterns confirmed that the crystalline and amorphous regions coexist in the silk fibers. The crystallites with β-sheet structure have an orthorhombic unit cell with lattice parameters: a=9.10 Å, b=9.71 Å and c=6.80 Å. The crystallite size, crystallite orientation and crystallinity were also estimated based on the WAXS patterns. The results demonstrate that the crystallite size is almost unchanged with the stretching strain. The crystallinity is approximately linearly increasing with the applied stretching force. However, the change of the unit-cell orientation degree with c-axis along the fiber axis behaves as a fast stage and an approximately unchanged stage during the in situ stretching process. All these experimental phenomena confirm that the microstructure of the degummed silk fibers can be well explained by the model of oriented β-sheet structure with a banded feature.
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Affiliation(s)
- Ku Liang
- National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083, China
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11
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Asakura T, Suzuki Y, Nakazawa Y, Yazawa K, Holland GP, Yarger JL. Silk structure studied with nuclear magnetic resonance. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 69:23-68. [PMID: 23465642 DOI: 10.1016/j.pnmrs.2012.08.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 08/13/2012] [Indexed: 06/01/2023]
Affiliation(s)
- Tetsuo Asakura
- Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
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12
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Feng XX, Guo YH, Chen JY, Zhang JC. Nano-TiO2 induced secondary structural transition of silk fibroin studied by two-dimensional Fourier-transform infrared correlation spectroscopy and Raman spectroscopy. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 18:1443-56. [DOI: 10.1163/156856207782246786] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Xin-Xing Feng
- a The State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065, P. R. China; The Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Yu-Hai Guo
- b The Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Jian-Yong Chen
- c The Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Jian-Chun Zhang
- d The State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065, P. R. China; The Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
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13
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Yoshioka T, Kawahara Y, Schaper AK. Cyclic or Permanent? Structure Control of the Contraction Behavior of Regenerated Bombyx mori Silk Nanofibers. Macromolecules 2011. [DOI: 10.1021/ma2014172] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Taiyo Yoshioka
- Materials Science Center, EM&Mlab, Philipps University of Marburg, Hans-Meerwein-Str., 35032 Marburg, Germany
| | - Yutaka Kawahara
- Department of Biological and Chemical Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Andreas K. Schaper
- Materials Science Center, EM&Mlab, Philipps University of Marburg, Hans-Meerwein-Str., 35032 Marburg, Germany
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14
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Sashina ES, Novoselov NP, Toroshekova SV, Petrenko VE. Quantum-chemical study of the mechanism of dissolution of scleroproteins in N-methylmorpholine N-oxide. RUSS J GEN CHEM+ 2011. [DOI: 10.1134/s1070363208010246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Sulfur hexafluoride plasma surface modification of Gly-Ala and Ala-Gly as Bombyx mori silk model compounds: Mechanism investigations. J Mol Struct 2010. [DOI: 10.1016/j.molstruc.2009.10.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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16
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Suzuki Y, Takahashi R, Shimizu T, Tansho M, Yamauchi K, Williamson MP, Asakura T. Intra- and Intermolecular Effects on 1H Chemical Shifts in a Silk Model Peptide Determined by High-Field Solid State 1H NMR and Empirical Calculations. J Phys Chem B 2009; 113:9756-61. [DOI: 10.1021/jp903020p] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yu Suzuki
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan, National Institute for Material Science, 3-13 Sakura, Tsukuba, Ibaraki 305-0003, Japan, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank Sheffield S10 2TN, U.K
| | - Rui Takahashi
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan, National Institute for Material Science, 3-13 Sakura, Tsukuba, Ibaraki 305-0003, Japan, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank Sheffield S10 2TN, U.K
| | - Tadashi Shimizu
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan, National Institute for Material Science, 3-13 Sakura, Tsukuba, Ibaraki 305-0003, Japan, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank Sheffield S10 2TN, U.K
| | - Masataka Tansho
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan, National Institute for Material Science, 3-13 Sakura, Tsukuba, Ibaraki 305-0003, Japan, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank Sheffield S10 2TN, U.K
| | - Kazuo Yamauchi
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan, National Institute for Material Science, 3-13 Sakura, Tsukuba, Ibaraki 305-0003, Japan, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank Sheffield S10 2TN, U.K
| | - Mike P. Williamson
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan, National Institute for Material Science, 3-13 Sakura, Tsukuba, Ibaraki 305-0003, Japan, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank Sheffield S10 2TN, U.K
| | - Tetsuo Asakura
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan, National Institute for Material Science, 3-13 Sakura, Tsukuba, Ibaraki 305-0003, Japan, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank Sheffield S10 2TN, U.K
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17
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Gus'kova OA, Khalatur PG, Khokhlov AR. Self-Assembled Polythiophene-Based Nanostructures: Numerical Studies. MACROMOL THEOR SIMUL 2009. [DOI: 10.1002/mats.200800090] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Gus’kova OA, Schillinger E, Khalatur PG, Bäuerle P, Khokhlov AR. Bioinspired hybrid systems based on oligothiophenes and peptides (ALA-GLY)n: Computer-aided simulation of adsorption layers. POLYMER SCIENCE SERIES A 2009. [DOI: 10.1134/s0965545x09040099] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Martel A, Burghammer M, Davies RJ, Di Cola E, Vendrely C, Riekel C. Silk fiber assembly studied by synchrotron radiation SAXS/WAXS and Raman spectroscopy. J Am Chem Soc 2009; 130:17070-4. [PMID: 19053481 DOI: 10.1021/ja806654t] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have characterized the steps involved in silk assembly from the protein solution into beta-type fibers by a combination of small-angle and wide-angle X-ray scattering and Raman spectroscopy. The aggregation process was studied in a concentric flow microfluidic cell, which allows mimicking the spinning duct. The fibroin molecule in solution shows an elongated shape with a maximum diameter of 38 nm. During the pH-driven initial assembly step, large-scale aggregates of fibroin molecules with a maximum diameter of about 260 nm are formed. Raman spectroscopy on the dried, fibrous material shows a principally alpha-helical silk I secondary structure, which is transformed gradually into beta-type silk II by increasing immersion times in water. The formation of crystalline beta-sheet domains within the fiber is confirmed by wide-angle X-ray scattering. The assembly process resembles the peptide condensation-ordering model proposed for amyloid cross-beta formation.
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Affiliation(s)
- Anne Martel
- European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex, France
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20
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Silk-inspired ‘molecular chimeras’: Atomistic simulation of nanoarchitectures based on thiophene–peptide copolymers. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.06.058] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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21
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Sashina ES, Bochek AM, Novoselov NP, Kirichenko DA. Structure and solubility of natural silk fibroin. RUSS J APPL CHEM+ 2006. [DOI: 10.1134/s1070427206060012] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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22
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Yao JM, Zhang GQ, Lei CH. Conformational Transformation Exhibited by the Peptide Extracted from Crystalline Region ofBombyx mori Silk Fibroin in Solid and Solution States. CHINESE J CHEM 2006. [DOI: 10.1002/cjoc.200690134] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Hofmann S, Foo CTWP, Rossetti F, Textor M, Vunjak-Novakovic G, Kaplan DL, Merkle HP, Meinel L. Silk fibroin as an organic polymer for controlled drug delivery. J Control Release 2006; 111:219-27. [PMID: 16458987 DOI: 10.1016/j.jconrel.2005.12.009] [Citation(s) in RCA: 245] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2005] [Revised: 12/14/2005] [Accepted: 12/19/2005] [Indexed: 11/27/2022]
Abstract
The pharmaceutical utility of silk fibroin (SF) materials for drug delivery was investigated. SF films were prepared from aqueous solutions of the fibroin protein polymer and crystallinity was induced and controlled by methanol treatment. Dextrans of different molecular weights, as well as proteins, were physically entrapped into the drug delivery device during processing into films. Drug release kinetics were evaluated as a function of dextran molecular weight, and film crystallinity. Treatment with methanol resulted in an increase in beta-sheet structure, an increase in crystallinity and an increase in film surface hydrophobicity determined by FTIR, X-ray and contact angle techniques, respectively. The increase in crystallinity resulted in the sustained release of dextrans of molecular weights ranging from 4 to 40 kDa, whereas for less crystalline films sustained release was confined to the 40 kDa dextran. Protein release from the films was studied with horseradish peroxidase (HRP) and lysozyme (Lys) as model compounds. Enzyme release from the less crystalline films resulted in a biphasic release pattern, characterized by an initial release within the first 36 h, followed by a lag phase and continuous release between days 3 and 11. No initial burst was observed for films with higher crystallinity and subsequent release patterns followed linear kinetics for HRP, or no substantial release for Lys. In conclusion, SF is an interesting polymer for drug delivery of polysaccharides and bioactive proteins due to the controllable level of crystallinity and the ability to process the biomaterial in biocompatible fashion under ambient conditions to avoid damage to labile compounds to be delivered.
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Affiliation(s)
- S Hofmann
- Drug Formulation and Delivery, ETH Zurich, 8093 Zurich, Switzerland
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Sangappa EY, Mahesh SS, Somashekar R. Crystal structure of raw pure Mysore silk fibre based on (Ala-Gly)2-Ser-Gly peptide sequence using Linked-Atom-Least-Squares method. J Biosci 2005; 30:259-68. [PMID: 15933415 DOI: 10.1007/bf02703707] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We have carried out crystal structure analysis of raw pure Mysore silk fibers belonging to Bombyx mori on the basis of model parameters of Marsh et al using Linked-Atom-Least-Squares technique. The intensity of all the reflections were computed employing CCP13 software. We observe that the molecular modification is essentially same as b-pleated structure with antipolar-antiparallel arrangements formed by hydrogen bonds. The essential differences observed in the structure are highlighted and discussed.
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Asakura T, Ohgo K, Komatsu K, Kanenari M, Okuyama K. Refinement of Repeated β-turn Structure for Silk I Conformation ofBombyx moriSilk Fibroin Using13C Solid-State NMR and X-ray Diffraction Methods. Macromolecules 2005. [DOI: 10.1021/ma050936y] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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Abstract
X-ray studies on degummed B. mori silk fibers and on hydrogels prepared under a variety of conditions reveal moderately small angle reflections. These reflections are often highly oriented and are correlated to silk II lattice reflections. A superstructure can explain these features. Silk fibroin hydrogels were monitored as they dried to form the silk II structure. The silk II wide angle and moderately small angle patterns obtained from dried hydrogels and silk fibers are identical. The "superstructure" reflections at moderately small angle (3-7 nm) were first to appear, followed by the "intersheet" spacing, and then the remainder of the silk II wide angle scattering pattern. Thus, any superstructure hypothesized for the hydrogels (and for Silk II in fibers) must be both stable in a highly hydrated environment and must convert to silk II with little large scale diffusion. A folded structure, similar to amyloids and cross-beta-sheets but with much longer beta-strand stems, is proposed for silk II in fibers.
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Affiliation(s)
- Regina Valluzzi
- Department of Chemical and Biological Engineering, Tufts University, 4 Colby Street, Medford, Massachusetts 02155, USA.
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Sangappa, Okuyama K, Somashekar R. Strain-tensor components, crystallite shape, and their effects on crystalline structure in silk I. J Appl Polym Sci 2004. [DOI: 10.1002/app.13521] [Citation(s) in RCA: 6] [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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Hino T, Tanimoto M, Shimabayashi S. Change in secondary structure of silk fibroin during preparation of its microspheres by spray-drying and exposure to humid atmosphere. J Colloid Interface Sci 2003; 266:68-73. [PMID: 12957583 DOI: 10.1016/s0021-9797(03)00584-8] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Silk microspheres prepared by spray-drying were exposed to humid atmosphere (89% relative humidity, RH). Change in the secondary structure of silk fibroin during preparation of silk microspheres and exposure to high humidity was studied. Scoured silk fiber was dissolved in an aqueous solution of calcium chloride mixed with ethanol. After dialysis against purified water, theophylline was added to the solution as a model drug. Silk microspheres were obtained by spray-drying. Silk fibroin and theophylline were found to be amorphous in the microsphere by means of powder X-ray diffractometry. Fibroin assumed a beta-sheet conformation in the scoured silk fiber while it has an irregular structure in the microsphere, according to FTIR and Raman spectra. Fibroin recrystallized and its secondary structure changed to beta-sheet conformation by exposure of the microspheres to an atmosphere of 89% RH.
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Affiliation(s)
- Tomoaki Hino
- Faculty of Pharmaceutical Sciences, The University of Tokushima, Sho-machi 1-78-1, Tokushima 770-8505, Japan.
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