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Presence of β-Turn Structure in Recombinant Spider Silk Dissolved in Formic Acid Revealed with NMR. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27020511. [PMID: 35056828 PMCID: PMC8778467 DOI: 10.3390/molecules27020511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 11/23/2022]
Abstract
Spider dragline silk is a biopolymer with excellent mechanical properties. The development of recombinant spider silk protein (RSP)-based materials with these properties is desirable. Formic acid (FA) is a spinning solvent for regenerated Bombyx mori silk fiber with excellent mechanical properties. To use FA as a spinning solvent for RSP with the sequence of major ampullate spider silk protein from Araneus diadematus, we determined the conformation of RSP in FA using solution NMR to determine the role of FA as a spinning solvent. We assigned 1H, 13C, and 15N chemical shifts to 32-residue repetitive sequences, including polyAla and Gly-rich regions of RSP. Chemical shift evaluation revealed that RSP is in mainly random coil conformation with partially type II β-turn structure in the Gly-Pro-Gly-X motifs of the Gly-rich region in FA, which was confirmed by the 15N NOE data. In addition, formylation at the Ser OH groups occurred in FA. Furthermore, we evaluated the conformation of the as-cast film of RSP dissolved in FA using solid-state NMR and found that β-sheet structure was predominantly formed.
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2
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Hirano A, Wada M, Sato TK, Kameda T. The solubility of N-acetyl amino acid amides in organic acid and alcohol solutions: Mechanistic insight into structural protein solubilization. Int J Biol Macromol 2021; 178:607-615. [PMID: 33631265 DOI: 10.1016/j.ijbiomac.2021.02.141] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 02/03/2021] [Accepted: 02/18/2021] [Indexed: 10/22/2022]
Abstract
Structural proteins such as spider silk and silkworm silk are generally poorly soluble in aqueous and organic solutions, making them difficult to manipulate in manufacturing processes. Although some organic acids and alcohols, such as formic acid and hexafluoroisopropanol (HFIP), effectively solubilize poorly soluble proteins, little is known about their protein solubilization mechanism. In this study, the solubility of N-acetyl amino acid amide compounds in organic solvents-formic acid, acetic acid, HFIP and isopropanol-was measured to clarify the protein solubilization mechanism at the amino acid residue level. On the basis of thermodynamic analyses of the solubility in terms of the transfer free energy (from water to organic solvents), every organic solvent was found to be effective in thermodynamically stabilizing hydrophobic amino acid side chains in the liquid phase. Formic acid and HFIP were comparably effective in the stabilization of the polypeptide backbone, whereas acetic acid and isopropanol were ineffective. Therefore, the significant solubilizing effect of formic acid and HFIP on the structural proteins was attributed to their favorable interactions with hydrophobic amino acid side chains and with the polypeptide backbone of the proteins. The present findings are useful for the optimization of protein manipulation and amino acid sequence design.
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Affiliation(s)
- Atsushi Hirano
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan.
| | - Momoyo Wada
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan
| | - Takehiro K Sato
- Spiber Inc., 234-1 Mizukami, Kakuganji, Tsuruoka, Yamagata 997-0052, Japan
| | - Tomoshi Kameda
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Koto, Tokyo 135-0064, Japan
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3
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4
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Dong Q, Fang G, Huang Y, Hu L, Yao J, Shao Z, Ling S, Chen X. Effect of stress on the molecular structure and mechanical properties of supercontracted spider dragline silks. J Mater Chem B 2020; 8:168-176. [PMID: 31789330 DOI: 10.1039/c9tb02032b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Supercontraction is one of the most interesting properties of spider dragline silks. In this study, changes in the secondary structures of the Nephila edulis spider dragline silk after it was subjected to different supercontraction processes were investigated by integrating synchrotron Fourier transform infrared (S-FTIR) microspectroscopy and mechanical characterization. The results showed that after free supercontraction, the β-sheet lost most of its orientation, while the helix and random coils were almost totally disordered. Interestingly, by conducting different types of supercontractions (i.e., stretching of the free supercontracted spider dragline silk to its original length or performing constrained supercontraction), it was found that although the molecular structures all changed after supercontraction, the mechanical properties almost remained unchanged when the length of the spider dragline silk did not change significantly. The other interesting conclusion obtained is that the manual stretching of a poorly oriented spider dragline silk cannot selectively improve the orientation degree of the β-sheet in the spider silk, but increase the orientation degree of all conformations (β-sheet, helix, and random). These experimental findings not only help to unveil the structure-property-function relationship of natural spider silks, but also provide a useful guideline for the design of biomimetic spider fiber materials.
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Affiliation(s)
- Qinglin Dong
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai, 200433, People's Republic of China.
| | - Guangqiang Fang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai, 200433, People's Republic of China.
| | - Yufang Huang
- Department of Materials Science, Fudan University, Shanghai, 200433, People's Republic of China
| | - Linli Hu
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai, 200433, People's Republic of China.
| | - Jinrong Yao
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai, 200433, People's Republic of China.
| | - Zhengzhong Shao
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai, 200433, People's Republic of China.
| | - Shengjie Ling
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, People's Republic of China.
| | - Xin Chen
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai, 200433, People's Republic of China.
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5
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Iachina I, Brewer JR. Strain-Dependent Structural Changes in Major and Minor Ampullate Spider Silk Revealed by Two-Photon Excitation Polarization. Biomacromolecules 2019; 20:2384-2391. [PMID: 31074979 DOI: 10.1021/acs.biomac.9b00368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Spider silk's mechanical properties make it an interesting material for many industrial applications. The structure and nanoscopic organization of its proteins are the basis of these qualities. In this study, the emission maxima of the autofluorescence from the protein core of major and minor ampullate silk fibers from the orb-web-weaving spider Nephila madagascariensis are determined and found to be 534 ± 11 and 547 ± 19 nm, respectively. Molecular conformational changes during applied strain are observed in both fiber types using two-photon excitation polarization measurements. Our findings showed that within the fibers the autofluorescent dipoles are separated into two distinct populations, one randomly orientated (amorphous regions) and one with aligned dipoles as found in crystalline structures. The crystalline-amorphous ratio was determined, and it was found that the crystalline dipoles made up around 30 and 20% of the autofluorescent dipoles in major and minor ampullate silk fibers, respectively. Using two-photon polarization measurements, it is possible to directly observe that the major and minor ampullate silk fibers structurally adapt to the applied stress, as well as discern different molecular conformational changes between major and minor ampullates. It was seen that the crystalline-amorphous ratio increased, with up to 9% for major fibers and 6% for minor fibers, as strain was applied, suggesting a conformational adaptation of the fiber, interpreted as noncrystalline 310-helices transforming into crystalline β-sheets.
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Affiliation(s)
- Irina Iachina
- Department of Biochemistry and Molecular Biology , University of Southern Denmark , 5230 Odense , Denmark
| | - Jonathan R Brewer
- Department of Biochemistry and Molecular Biology , University of Southern Denmark , 5230 Odense , Denmark
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6
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Whaite AD, Wang T, Macdonald J, Cummins SF. Major ampullate silk gland transcriptomes and fibre proteomes of the golden orb-weavers, Nephila plumipes and Nephila pilipes (Araneae: Nephilidae). PLoS One 2018; 13:e0204243. [PMID: 30332416 PMCID: PMC6192577 DOI: 10.1371/journal.pone.0204243] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 09/04/2018] [Indexed: 11/18/2022] Open
Abstract
Natural spider silk is one of the world’s toughest proteinaceous materials, yet a truly biomimetic spider silk is elusive even after several decades of intense focus. In this study, Next-Generation Sequencing was utilised to produce transcriptomes of the major ampullate gland of two Australian golden orb-weavers, Nephila plumipes and Nephila pilipes, in order to identify highly expressed predicted proteins that may co-factor in the construction of the final polymer. Furthermore, proteomics was performed by liquid chromatography tandem-mass spectroscopy to analyse the natural solid silk fibre of each species to confirm highly expressed predicted proteins within the silk gland are present in the final silk product. We assembled the silk gland transcriptomes of N. plumipes and N. pilipes into 69,812 and 70,123 contigs, respectively. Gene expression analysis revealed that silk gene sequences were among the most highly expressed and we were able to procure silk sequences from both species in excess of 1,300 amino acids. However, some of the genes with the highest expression values were not able to be identified from our proteomic analysis. Proteome analysis of “reeled” silk fibres of N. plumipes and N. pilipes revealed 29 and 18 proteins, respectively, most of which were identified as silk fibre proteins. This study is the first silk gland specific transcriptome and proteome analysis for these species and will assist in the future development of a biomimetic spider silk.
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Affiliation(s)
- Alessandra D Whaite
- GeneCology Research Centre and School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Tianfang Wang
- GeneCology Research Centre and School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Joanne Macdonald
- GeneCology Research Centre and School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia.,Division of Experimental Therapeutics, Columbia University, New York City, New York, United States of America
| | - Scott F Cummins
- GeneCology Research Centre and School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
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Wu HC, Wu SR, Yang TCK, Yang JC. A Facile Measurement for Monitoring Dragline Silk Dope Concentration in Nephila pilipes upon Spinning. MATERIALS (BASEL, SWITZERLAND) 2018; 11:E1951. [PMID: 30321988 PMCID: PMC6213051 DOI: 10.3390/ma11101951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 09/24/2018] [Accepted: 10/05/2018] [Indexed: 11/16/2022]
Abstract
In spite of all the efforts towards deciphering the silk spinning process of spiders, the underlying mechanism is yet to be fully revealed. In this research, we designed a novel approach that allowed us to quantitatively evaluate the concentration change of silk dope during the liquid-to-solid spinning process of the orb-weaver Nephila pilipes. As a prior characterization of the optimal silking conditions, we first gauged the influence of silking-rate, ranging from 1.5 to 8.0 m/min, on dragline silk diameters and silk tensile strengths obtained from the spiders. Next, to evaluate the liquid content of the silk dope, the major ampullate gland was dissected and the concentration of the sac portion was measured by thermogravimetric analysis (TGA). The solid content of the dragline fibers leaving the spinneret was investigated by calculating the ratio of collected dried silk to the weight loss of the spider recorded in situ upon spinning. As the results indicate, the tensile strength and diameter of the spun dragline fibers were 800⁻1100 MPa and 8⁻11 μm, respectively. The liquid content of silk stored in the major ampullate sac (50.0 wt%) was significantly lower than that of silk leaving the spinnerets (80.9⁻96.1 wt%), indicating that a liquid supplying mechanism might be involved during the spinning process. This reveals, for the first time, quantitative evidence in support of the lubricative hypothesis proposed formerly, namely that a liquid coating layer is supplemented to compensate for silking resistance during the spinning process of a spider. The spigot, at the exit of the spinneret, is speculated to serve as a valve-like controller that regulates the lubrication process along with fiber formation. Taken together, these findings provide understanding of the physiological functions in the spider spinning process and could further shed some light on the future biomimetic development of silk material fabrication.
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Affiliation(s)
- Hsuan-Chen Wu
- Department of Biochemical Science and Technology, National Taiwan University, Taipei 106, Taiwan.
- Research Center for Biomedical Devices and Prototyping Production, Taipei Medical University, Taipei 110, Taiwan.
| | - Shang-Ru Wu
- Department of Biochemical Science and Technology, National Taiwan University, Taipei 106, Taiwan.
| | - Thomas Chung-Kuang Yang
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei 106, Taiwan.
| | - Jen-Chang Yang
- Research Center for Biomedical Devices and Prototyping Production, Taipei Medical University, Taipei 110, Taiwan.
- Graduate Institute of Nanomedicine and Medical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 110, Taiwan.
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8
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Sparkes J, Holland C. The rheological properties of native sericin. Acta Biomater 2018; 69:234-242. [PMID: 29408618 DOI: 10.1016/j.actbio.2018.01.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/13/2017] [Accepted: 01/16/2018] [Indexed: 11/29/2022]
Abstract
Unlike spider silk, spinning silkworm silk has the added intricacy of being both fibre and micron-thick glue-like coating. Whilst the natural flow properties of the fibre feedstock fibroin are now becoming more established, our understanding of the coating sericin is extremely limited and thus presents both a gap in our knowledge and a hindrance to successful exploitation of these materials. In this study we characterise sericin feedstock from the silkworm Bombyx mori in its native state and by employing both biochemical, rheological and spectroscopic tools, define a natural gold standard. Our results demonstrate that native sericin behaves as a viscoelastic shear thinning fluid, but that it does so at a considerably lower viscosity than its partner fibroin, and that its upper critical shear rate (onset of gelation) lies above that of fibroin. Together these findings provide the first evidence that in addition to acting as a binder in the construction of the cocoon, sericin is capable of lubricating the flow of fibroin within the silk gland, which has implications for future processing, modelling and biomimetic use of these materials. STATEMENT OF SIGNIFICANCE This study addresses one of the major gaps in our knowledge regarding natural silk spinning by providing rigorous rheological characterisation of the other major protein involved - sericin. This allows progress in silk flow modelling, biomimetic system design, and in assessing the quality of bioinspired and waste sericin materials by providing a better understanding of the native, undegraded system.
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Affiliation(s)
- James Sparkes
- Department of Materials Science and Engineering, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S. Yorks S1 3JD, UK
| | - Chris Holland
- Department of Materials Science and Engineering, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S. Yorks S1 3JD, UK.
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9
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He Z, Liu Z, Zhou X, Huang H. Low pressure-induced secondary structure transitions of regenerated silk fibroin in its wet film studied by time-resolved infrared spectroscopy. Proteins 2018; 86:621-628. [DOI: 10.1002/prot.25488] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 02/08/2018] [Accepted: 02/24/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Zhipeng He
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Key Laboratory for the Design and Application of Advanced Functional Polymer, College of Chemistry, Chemical Engineering and Materials Science; Soochow University; Suzhou 215123 China
| | - Zhao Liu
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Key Laboratory for the Design and Application of Advanced Functional Polymer, College of Chemistry, Chemical Engineering and Materials Science; Soochow University; Suzhou 215123 China
| | - Xiaofeng Zhou
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Key Laboratory for the Design and Application of Advanced Functional Polymer, College of Chemistry, Chemical Engineering and Materials Science; Soochow University; Suzhou 215123 China
| | - He Huang
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Key Laboratory for the Design and Application of Advanced Functional Polymer, College of Chemistry, Chemical Engineering and Materials Science; Soochow University; Suzhou 215123 China
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10
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Fink TD, Zha RH. Silk and Silk-Like Supramolecular Materials. Macromol Rapid Commun 2018; 39:e1700834. [DOI: 10.1002/marc.201700834] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 01/16/2018] [Indexed: 01/12/2023]
Affiliation(s)
- Tanner D. Fink
- Department of Chemical and Biological Engineering; Center for Biotechnology and Interdisciplinary Studies; Rensselaer Polytechnic Institute; 110 8th St. Troy NY 12180 USA
| | - R. Helen Zha
- Department of Chemical and Biological Engineering; Center for Biotechnology and Interdisciplinary Studies; Rensselaer Polytechnic Institute; 110 8th St. Troy NY 12180 USA
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11
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Yoshioka T, Hata T, Kojima K, Nakazawa Y, Kameda T. Fabrication Scheme for Obtaining Transparent, Flexible, and Water-Insoluble Silk Films from Apparently Dissolved Silk-Gland Fibroin of Bombyx mori Silkworm. ACS Biomater Sci Eng 2017; 3:3207-3214. [DOI: 10.1021/acsbiomaterials.7b00602] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Taiyo Yoshioka
- Silk
Materials Research Unit, National Agriculture and Food Research Organization (NARO), 1-2 Ohwashi, Tsukuba, Ibaraki 305-8634, Japan
| | - Tamako Hata
- Silk
Materials Research Unit, National Agriculture and Food Research Organization (NARO), 1-2 Ohwashi, Tsukuba, Ibaraki 305-8634, Japan
| | - Katsura Kojima
- Silk
Materials Research Unit, National Agriculture and Food Research Organization (NARO), 1-2 Ohwashi, Tsukuba, Ibaraki 305-8634, Japan
| | - Yasumoto Nakazawa
- Division
of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
| | - Tsunenori Kameda
- Silk
Materials Research Unit, National Agriculture and Food Research Organization (NARO), 1-2 Ohwashi, Tsukuba, Ibaraki 305-8634, Japan
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12
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Affiliation(s)
- Yun Jung Yang
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Angela L. Holmberg
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Bradley D. Olsen
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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13
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Koeppel A, Holland C. Progress and Trends in Artificial Silk Spinning: A Systematic Review. ACS Biomater Sci Eng 2017; 3:226-237. [DOI: 10.1021/acsbiomaterials.6b00669] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Andreas Koeppel
- Department of Materials
Science
and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom
| | - Chris Holland
- Department of Materials
Science
and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom
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14
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Blamires SJ, Blackledge TA, Tso IM. Physicochemical Property Variation in Spider Silk: Ecology, Evolution, and Synthetic Production. ANNUAL REVIEW OF ENTOMOLOGY 2017; 62:443-460. [PMID: 27959639 DOI: 10.1146/annurev-ento-031616-035615] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The unique combination of great stiffness, strength, and extensibility makes spider major ampullate (MA) silk desirable for various biomimetic and synthetic applications. Intensive research on the genetics, biochemistry, and biomechanics of this material has facilitated a thorough understanding of its properties at various levels. Nevertheless, methods such as cloning, recombination, and electrospinning have not successfully produced materials with properties as impressive as those of spider silk. It is nevertheless becoming clear that silk properties are a consequence of whole-organism interactions with the environment in addition to genetic expression, gland biochemistry, and spinning processes. Here we assimilate the research done and assess the techniques used to determine distinct forms of spider silk chemical and physical property variability. We suggest that more research should focus on testing hypotheses that explain spider silk property variations in ecological and evolutionary contexts.
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Affiliation(s)
- Sean J Blamires
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan;
- Evolution & Ecology Research Centre, School of Biological, Earth & Environmental Sciences, The University of New South Wales, Sydney 2052, Australia;
| | - Todd A Blackledge
- Department of Biology, Integrated Bioscience Program, The University of Akron, Akron, Ohio 44325;
| | - I-Min Tso
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan;
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15
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Sutherland TD, Rapson TD, Huson MG, Church JS. Recombinant Structural Proteins and Their Use in Future Materials. Subcell Biochem 2017; 82:491-526. [PMID: 28101871 DOI: 10.1007/978-3-319-49674-0_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Recombinant proteins are polymers that offer the materials engineer absolute control over chain length and composition: key attributes required for design of advanced polymeric materials. Through this control, these polymers can be encoded to contain information that enables them to respond as the environment changes. However, despite their promise, protein-based materials are under-represented in materials science. In this chapter we investigate why this is and describe recent efforts to address this. We discuss constraints limiting rational design of structural proteins for advanced materials; advantages and disadvantages of different recombinant expression platforms; and, methods to fabricate proteins into solid-state materials. Finally, we describe the silk proteins used in our laboratory as templates for information-containing polymers.
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16
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Jones JA, Harris TI, Oliveira PF, Bell BE, Alhabib A, Lewis RV. Importance of Heat and Pressure for Solubilization of Recombinant Spider Silk Proteins in Aqueous Solution. Int J Mol Sci 2016; 17:ijms17111955. [PMID: 27886066 PMCID: PMC5133949 DOI: 10.3390/ijms17111955] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 11/11/2016] [Accepted: 11/18/2016] [Indexed: 01/23/2023] Open
Abstract
The production of recombinant spider silk proteins continues to be a key area of interest for a number of research groups. Several key obstacles exist in their production as well as in their formulation into useable products. The original reported method to solubilize recombinant spider silk proteins (rSSp) in an aqueous solution involved using microwaves to quickly generate heat and pressure inside of a sealed vial containing rSSp and water. Fibers produced from this system are remarkable in their mechanical ability and demonstrate the ability to be stretched and recover 100 times. The microwave method dissolves the rSSPs with dissolution time increasing with higher molecular weight constructs, increasing concentration of rSSPs, protein type, and salt concentration. It has proven successful in solvating a number of different rSSPs including native-like sequences (MaSp1, MaSp2, piriform, and aggregate) as well as chimeric sequences (FlAS) in varied concentrations that have been spun into fibers and formed into films, foams, sponges, gels, coatings, macro and micro spheres and adhesives. The system is effective but inherently unpredictable and difficult to control. Provided that the materials that can be generated from this method of dissolution are impressive, an alternative means of applying heat and pressure that is controllable and predictable has been developed. Results indicate that there are combinations of heat and pressure (135 °C and 140 psi) that result in maximal dissolution without degrading the recombinant MaSp2 protein tested, and that heat and pressure are the key elements to the method of dissolution.
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Affiliation(s)
- Justin A Jones
- Department of Biology, Utah State University, Logan, UT 84341, USA.
| | - Thomas I Harris
- Department of Biological Engineering, Utah State University, Logan, UT 84341, USA.
| | - Paula F Oliveira
- Department of Biology, Utah State University, Logan, UT 84341, USA.
| | - Brianne E Bell
- Department of Biology, Utah State University, Logan, UT 84341, USA.
| | | | - Randolph V Lewis
- Department of Biology, Utah State University, Logan, UT 84341, USA.
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17
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Xie L, Xu H, Li LB, Hsiao BS, Zhong GJ, Li ZM. Biomimetic Nanofibrillation in Two-Component Biopolymer Blends with Structural Analogs to Spider Silk. Sci Rep 2016; 6:34572. [PMID: 27694989 PMCID: PMC5046138 DOI: 10.1038/srep34572] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 09/16/2016] [Indexed: 11/09/2022] Open
Abstract
Despite the enormous potential in bioinspired fabrication of high-strength structure by mimicking the spinning process of spider silk, currently accessible routes (e.g., microfluidic and electrospinning approaches) still have substantial function gaps in providing precision control over the nanofibrillar superstructure, crystalline morphology or molecular orientation. Here the concept of biomimetic nanofibrillation, by copying the spiders’ spinning principles, was conceived to build silk-mimicking hierarchies in two-phase biodegradable blends, strategically involving the stepwise integration of elongational shear and high-pressure shear. Phase separation confined on nanoscale, together with deformation of discrete phases and pre-alignment of polymer chains, was triggered in the elongational shear, conferring the readiness for direct nanofibrillation in the latter shearing stage. The orderly aligned nanofibrils, featuring an ultralow diameter of around 100 nm and the “rigid−soft” system crosslinked by nanocrystal domains like silk protein dopes, were secreted by fine nanochannels. The incorporation of multiscale silk-mimicking structures afforded exceptional combination of strength, ductility and toughness for the nanofibrillar polymer composites. The proposed spider spinning-mimicking strategy, offering the biomimetic function integration unattainable with current approaches, may prompt materials scientists to pursue biopolymer mimics of silk with high performance yet light weight.
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Affiliation(s)
- Lan Xie
- Department of Polymer Materials and Engineering, College of Materials and Metallurgy, Guizhou University, Guiyang 550025, China
| | - Huan Xu
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, China
| | - Liang-Bin Li
- National Synchrotron Radiation Lab, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Benjamin S Hsiao
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Gan-Ji Zhong
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, China
| | - Zhong-Ming Li
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, China
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Peng CA, Russo J, Gravgaard C, McCartney H, Gaines W, Marcotte WR. Spider silk-like proteins derived from transgenic Nicotiana tabacum. Transgenic Res 2016; 25:517-26. [PMID: 27026165 DOI: 10.1007/s11248-016-9949-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 03/03/2016] [Indexed: 10/22/2022]
Abstract
The high tensile strength and biocompatibility of spider dragline silk makes it a desirable material in many engineering and tissue regeneration applications. Here, we present the feasibility to produce recombinant proteins in transgenic tobacco Nicotiana tabacum with sequences representing spider silk protein building blocks . Recombinant mini-spidroins contain native N- and C-terminal domains of major ampullate spidroin 1 (rMaSp1) or rMaSp2 flanking an abbreviated number (8, 16 or 32) of consensus repeat domains. Two different expression plasmid vectors were tested and a downstream chitin binding domain and self-cleavable intein were included to facilitate protein purification. We confirmed gene insertion and RNA transcription by PCR and reverse-transcriptase PCR, respectively. Mini-spidroin production was detected by N-terminus specific antibodies. Purification of mini-spidroins was performed through chitin affinity chromatography and subsequent intein activation with reducing reagent. Mini-spidroins, when dialyzed and freeze-dried, formed viscous gelatin-like fluids.
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Affiliation(s)
- Congyue Annie Peng
- Department of Genetics and Biochemistry, Clemson University, 130 McGinty Court, 153 Robert F. Poole Agricultural Center, Clemson, SC, 29634, USA
| | - Julia Russo
- Department of Genetics and Biochemistry, Clemson University, 130 McGinty Court, 153 Robert F. Poole Agricultural Center, Clemson, SC, 29634, USA
| | - Charlene Gravgaard
- Department of Genetics and Biochemistry, Clemson University, 130 McGinty Court, 153 Robert F. Poole Agricultural Center, Clemson, SC, 29634, USA
- College of Pharmacy, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Heather McCartney
- Department of Genetics and Biochemistry, Clemson University, 130 McGinty Court, 153 Robert F. Poole Agricultural Center, Clemson, SC, 29634, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - William Gaines
- Department of Genetics and Biochemistry, Clemson University, 130 McGinty Court, 153 Robert F. Poole Agricultural Center, Clemson, SC, 29634, USA
| | - William R Marcotte
- Department of Genetics and Biochemistry, Clemson University, 130 McGinty Court, 153 Robert F. Poole Agricultural Center, Clemson, SC, 29634, USA.
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Yoshioka T, Tashiro K, Ohta N. Molecular Orientation Enhancement of Silk by the Hot-Stretching-Induced Transition from α-Helix-HFIP Complex to β-Sheet. Biomacromolecules 2016; 17:1437-48. [PMID: 26974170 DOI: 10.1021/acs.biomac.6b00043] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Enhancing the molecular orientation of the regenerated silk fibroin (RF) up to a level comparable to the native silk is highly challenging. Our novel and promising strategy for the poststretching process is (1) creating at first an α-helix-HFIP complex with a hexagonal packing as an intermediate state and then (2) stretching it at a high temperature to induce the helix-to-sheet structural phase transition. Here we show for the first time the significantly high stretching efficiency of the proposed technique compared with the conventional wet-stretching techniques and the successful achievement of higher crystalline orientation and higher Young's modulus compared even with the native silk. The detailed structural analysis based on the time-resolved simultaneous measurement of stress-strain curve, synchrotron X-ray scatterings, and FTIR has revealed the structural transition mechanism from the hexagonally packed α-helix-HFIP complex to the highly oriented β-sheet crystalline state as well as the critical level of crystal orientation needed for the helix-to-sheet transition.
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Affiliation(s)
- Taiyo Yoshioka
- Department of Future Industry-oriented Basic Science and Materials, Graduate School of Engineering, Toyota Technological Institute , Tempaku, Nagoya 468-8511, Japan
| | - Kohji Tashiro
- Department of Future Industry-oriented Basic Science and Materials, Graduate School of Engineering, Toyota Technological Institute , Tempaku, Nagoya 468-8511, Japan
| | - Noboru Ohta
- Japan Synchrotron Radiation Research Institute , 1-1 Koto, Mikazuki-cho, Sayo-gun, Hyogo 679-5198, Japan
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To spin or not to spin: spider silk fibers and more. Appl Microbiol Biotechnol 2015; 99:9361-80. [DOI: 10.1007/s00253-015-6948-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Revised: 08/16/2015] [Accepted: 08/20/2015] [Indexed: 12/18/2022]
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Majumder S, Kaulaskar MD, Neogi S. “Biosteel”: an exciting product from nature that is superior to many manmade alternatives. REV CHEM ENG 2015. [DOI: 10.1515/revce-2014-0055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractBiotechnology continues to offer routes for many exciting and unique products. Researchers genetically altered goats with a spider gene. These goats produce milk that contains a protein that can be extracted to produce biosteel fibers for use in bulletproof vests. It is referred to as “biosteel” to highlight its strength comparable to steel. This review paper describes the important aspects of produced dragline spider silk proteins via cell culture techniques using silk genes derived from two species of weaving spiders. These fibers were tested for a number of mechanical properties and compared to natural spider silk. In effect, fibers of biosteel were able to absorb similar amounts of energy as natural spider silk by stretching further. As opposed to most other synthetic fibers, biosteel is ecofriendly both in terms of its composition and production process.
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Jenkins JE, Sampath S, Butler E, Kim J, Henning RW, Holland GP, Yarger JL. Characterizing the secondary protein structure of black widow dragline silk using solid-state NMR and X-ray diffraction. Biomacromolecules 2013; 14:3472-83. [PMID: 24024617 PMCID: PMC3914425 DOI: 10.1021/bm400791u] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study provides a detailed secondary structural characterization of major ampullate dragline silk from Latrodectus hesperus (black widow) spiders. X-ray diffraction results show that the structure of black widow major ampullate silk fibers is comprised of stacked β-sheet nanocrystallites oriented parallel to the fiber axis and an amorphous region with oriented (anisotropic) and isotropic components. The combination of two-dimensional (2D) (13)C-(13)C through-space and through-bond solid-state NMR experiments provide chemical shifts that are used to determine detailed information about the amino acid motif secondary structure in black widow spider dragline silk. Individual amino acids are incorporated into different repetitive motifs that make up the majority of this protein-based biopolymer. From the solid-state NMR measurements, we assign distinct secondary conformations to each repetitive amino acid motif and, hence, to the amino acids that make up the motifs. Specifically, alanine is incorporated in β-sheet (poly(Alan) and poly(Gly-Ala)), 3(1)-helix (poly(Gly-Gly-Xaa), and α-helix (poly(Gln-Gln-Ala-Tyr)) components. Glycine is determined to be in β-sheet (poly(Gly-Ala)) and 3(1)-helical (poly(Gly-Gly-X(aa))) regions, while serine is present in β-sheet (poly(Gly-Ala-Ser)), 3(1)-helix (poly(Gly-Gly-Ser)), and β-turn (poly(Gly-Pro-Ser)) structures. These various motif-specific secondary structural elements are quantitatively correlated to the primary amino acid sequence of major ampullate spidroin 1 and 2 (MaSp1 and MaSp2) and are shown to form a self-consistent model for black widow dragline silk.
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Affiliation(s)
- Janelle E. Jenkins
- Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, Arizona 85287-1604, USA
| | - Sujatha Sampath
- Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, Arizona 85287-1604, USA
- Department of Physics, University of Wisconsin, Milwaukee, WI 53211
| | - Emily Butler
- Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, Arizona 85287-1604, USA
| | - Jihyun Kim
- Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, Arizona 85287-1604, USA
| | - Robert W. Henning
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, IL 60637
| | - Gregory P. Holland
- Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, Arizona 85287-1604, USA
| | - Jeffery L. Yarger
- Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, Arizona 85287-1604, USA
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Albertson AE, Teulé F, Weber W, Yarger JL, Lewis RV. Effects of different post-spin stretching conditions on the mechanical properties of synthetic spider silk fibers. J Mech Behav Biomed Mater 2013; 29:225-34. [PMID: 24113297 DOI: 10.1016/j.jmbbm.2013.09.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 08/27/2013] [Accepted: 09/01/2013] [Indexed: 10/26/2022]
Abstract
Spider silk is a biomaterial with impressive mechanical properties, resulting in various potential applications. Recent research has focused on producing synthetic spider silk fibers with the same mechanical properties as the native fibers. For this study, three proteins based on the Argiope aurantia Major ampullate Spidroin 2 consensus repeat sequence were expressed, purified and spun into fibers. A number of post-spin draw conditions were tested to determine the effect of each condition on the mechanical properties of the fiber. In all cases, post-spin stretching improved the mechanical properties of the fibers. Aqueous isopropanol was the most effective solution for increasing extensibility, while other solutions worked best for each fiber type for increasing tensile strength. The strain values of the stretched fibers correlated with the length of the proline-rich protein sequence. Structural analysis, including X-ray diffraction and Raman spectroscopy, showed surprisingly little change in the initial as-spun fibers compared with the post-spin stretched fibers.
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Affiliation(s)
- Amy E Albertson
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA.
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Adrianos SL, Teulé F, Hinman MB, Jones JA, Weber WS, Yarger JL, Lewis RV. Nephila clavipes Flagelliform silk-like GGX motifs contribute to extensibility and spacer motifs contribute to strength in synthetic spider silk fibers. Biomacromolecules 2013; 14:1751-60. [PMID: 23646825 DOI: 10.1021/bm400125w] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Flagelliform spider silk is the most extensible silk fiber produced by orb weaver spiders, though not as strong as the dragline silk of the spider. The motifs found in the core of the Nephila clavipes flagelliform Flag protein are GGX, spacer, and GPGGX. Flag does not contain the polyalanine motif known to provide the strength of dragline silk. To investigate the source of flagelliform fiber strength, four recombinant proteins were produced containing variations of the three core motifs of the Nephila clavipes flagelliform Flag protein that produces this type of fiber. The as-spun fibers were processed in 80% aqueous isopropanol using a standardized process for all four fiber types, which produced improved mechanical properties. Mechanical testing of the recombinant proteins determined that the GGX motif contributes extensibility and the spacer motif contributes strength to the recombinant fibers. Recombinant protein fibers containing the spacer motif were stronger than the proteins constructed without the spacer that contained only the GGX motif or the combination of the GGX and GPGGX motifs. The mechanical and structural X-ray diffraction analysis of the recombinant fibers provide data that suggests a functional role of the spacer motif that produces tensile strength, though the spacer motif is not clearly defined structurally. These results indicate that the spacer is likely a primary contributor of strength, with the GGX motif supplying mobility to the protein network of native N. clavipes flagelliform silk fibers.
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Affiliation(s)
- Sherry L Adrianos
- Department of Molecular Biology, University of Wyoming , Laramie, Wyoming 82071, United States.
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Arcidiacono S, Welsh EA, Soares JW. Aqueous-based spinning of fibers from self-assembling structural proteins. Methods Mol Biol 2013; 996:43-59. [PMID: 23504417 DOI: 10.1007/978-1-62703-354-1_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
There has been long-standing interest in generating fibers from structural proteins and a great deal of work has been done in attempting to mimic dragline spider silk. Dragline silk balances stiffness, strength, extensibility, and high energy to break. Mimicking these properties through aqueous-based spinning of recombinant silk protein is a significant challenge; however, an approach has been developed that facilitates the formation of fibers approaching the mechanical properties seen with natural dragline silk. Due to the multitude of solution, spinning and post-spinning variables one has to consider, the method entails a multivariate approach to protein solution processing and fiber spinning. Optimization to maximize mechanical integrity of the fibers is performed by correlating the solution and spinning variables to mechanical properties and using this information for subsequent fiber spinning studies. Here, the method is described in detail and emphasizes the lessons learned during the iterative variable analysis process, which can be used as a basis for aqueous-based fiber spinning of other structural proteins.
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Affiliation(s)
- Steven Arcidiacono
- U.S. Army Natick Soldier Research, Development & Engineering Center, Natick, MA, USA
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27
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Sampath S, Isdebski T, Jenkins JE, Ayon JV, Henning RW, Orgel JPRO, Antipoa O, Yarger JL. X-ray diffraction study of nanocrystalline and amorphous structure within major and minor ampullate dragline spider silks. SOFT MATTER 2012; 8:6713-6722. [PMID: 23569461 PMCID: PMC3617558 DOI: 10.1039/c2sm25373a] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Synchrotron X-ray micro-diffraction experiments were carried out on Nephila clavipes (NC) and Argiope aurantia (AA) major (MA) and minor ampullate (MiA) fibers that make up dragline spider silk. The diffraction patterns show a semi-crystalline structure with β-poly(l-alanine) nanocrystallites embedded in a partially oriented amorphous matrix. A superlattice reflection 'S' diffraction ring is observed, which corresponds to a crystalline component larger in size and is poorly oriented, when compared to the β-poly(l-alanine) nanocrystallites that are commonly observed in dragline spider silks. Crystallite size, crystallinity and orientation about the fiber axis have been determined from the wide-angle X-ray diffraction (WAXD) patterns. In both NC and AA, the MiA silks are found to be more highly crystalline, when compared with the corresponding MA silks. Detailed analysis on the amorphous matrix shows considerable differences in the degree of order of the oriented amorphous component between the different silks studied and may play a crucial role in determining the mechanical properties of the silks.
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Affiliation(s)
- Sujatha Sampath
- Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ, 85287-1604, USA
| | - Thomas Isdebski
- Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ, 85287-1604, USA
| | - Janelle E. Jenkins
- Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ, 85287-1604, USA
| | - Joel V. Ayon
- Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ, 85287-1604, USA
| | - Robert W. Henning
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, IL 60637, USA
| | - Joseph P. R. O. Orgel
- Department of Biological and Chemical Sciences, Pritzker Institute of Biomedical Science and Engineering, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Olga Antipoa
- Department of Biological and Chemical Sciences, Pritzker Institute of Biomedical Science and Engineering, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Jeffery L. Yarger
- Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ, 85287-1604, USA
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28
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Keerl D, Scheibel T. Characterization of natural and biomimetic spider silk fibers. BIOINSPIRED BIOMIMETIC AND NANOBIOMATERIALS 2012. [DOI: 10.1680/bbn.11.00016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Pelit L, Ertaş FN, Eroğlu AE, Shahwan T, Tural H. Biosorption of Cu(II) and Pb(II) ions from aqueous solution by natural spider silk. BIORESOURCE TECHNOLOGY 2011; 102:8807-8813. [PMID: 21803575 DOI: 10.1016/j.biortech.2011.07.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 06/26/2011] [Accepted: 07/06/2011] [Indexed: 05/31/2023]
Abstract
Aside from its excellent mechanical properties, spider silk (SS) would offer an active surface for heavy metal interaction due to its rich protein structure. The present study describes the potential use of natural (SS) as a sorbent of heavy metals from aqueous solutions. Single and multi-species biosorption experiments of heavy metals by natural SS were conducted using batch and column experiments. The biosorption kinetics, in general, was found to follow the second-order rate expression, and the experimental equilibrium biosorption data fitted reasonably well to Freundlich isotherm. From the Freundlich isotherm, the biosorption capacities of Cu(II) and Pb(II) ions onto SS were found as 0.20 and 0.007 mmol g⁻¹, respectively. The results showed a decrease in the extent of metal ion uptake with lowering the pH.
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Affiliation(s)
- L Pelit
- Department of Chemistry, Ege University, Faculty of Science, Bornova 35100, İzmir, Turkey.
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30
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Kushner AM, Guan Z. Modulares Design in natürlichen und biomimetischen elastischen Materialien. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201006496] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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31
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Kushner AM, Guan Z. Modular design in natural and biomimetic soft materials. Angew Chem Int Ed Engl 2011; 50:9026-57. [PMID: 21898722 DOI: 10.1002/anie.201006496] [Citation(s) in RCA: 174] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2010] [Indexed: 11/09/2022]
Abstract
Under eons of evolutionary and environmental pressure, biological systems have developed strong and lightweight peptide-based polymeric materials by using the 20 naturally occurring amino acids as principal monomeric units. These materials outperform their man-made counterparts in the following ways: 1) multifunctionality/tunability, 2) adaptability/stimuli-responsiveness, 3) synthesis and processing under ambient and aqueous conditions, and 4) recyclability and biodegradability. The universal design strategy that affords these advanced properties involves "bottom-up" synthesis and modular, hierarchical organization both within and across multiple length-scales. The field of "biomimicry"-elucidating and co-opting nature's basic material design principles and molecular building blocks-is rapidly evolving. This Review describes what has been discovered about the structure and molecular mechanisms of natural polymeric materials, as well as the progress towards synthetic "mimics" of these remarkable systems.
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Affiliation(s)
- Aaron M Kushner
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA
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32
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Eadie L, Ghosh TK. Biomimicry in textiles: past, present and potential. An overview. J R Soc Interface 2011; 8:761-75. [PMID: 21325320 DOI: 10.1098/rsif.2010.0487] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The natural world around us provides excellent examples of functional systems built with a handful of materials. Throughout the millennia, nature has evolved to adapt and develop highly sophisticated methods to solve problems. There are numerous examples of functional surfaces, fibrous structures, structural colours, self-healing, thermal insulation, etc., which offer important lessons for the textile products of the future. This paper provides a general overview of the potential of bioinspired textile structures by highlighting a few specific examples of pertinent, inherently sustainable biological systems. Biomimetic research is a rapidly growing field and its true potential in the development of new and sustainable textiles can only be realized through interdisciplinary research rooted in a holistic understanding of nature.
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Affiliation(s)
- Leslie Eadie
- Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, NC 27695, USA
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33
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Fudge DS, Hillis S, Levy N, Gosline JM. Hagfish slime threads as a biomimetic model for high performance protein fibres. BIOINSPIRATION & BIOMIMETICS 2010; 5:035002. [PMID: 20729569 DOI: 10.1088/1748-3182/5/3/035002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Textile manufacturing is one of the largest industries in the world, and synthetic fibres represent two-thirds of the global textile market. Synthetic fibres are manufactured from petroleum-based feedstocks, which are becoming increasingly expensive as demand for finite petroleum reserves continues to rise. For the last three decades, spider silks have been held up as a model that could inspire the production of protein fibres exhibiting high performance and ecological sustainability, but unfortunately, artificial spider silks have yet to fulfil this promise. Previous work on the biomechanics of protein fibres from the slime of hagfishes suggests that these fibres might be a superior biomimetic model to spider silks. Based on the fact that the proteins within these 'slime threads' adopt conformations that are similar to those in spider silks when they are stretched, we hypothesized that draw processing of slime threads should yield fibres that are comparable to spider dragline silk in their mechanical performance. Here we show that draw-processed slime threads are indeed exceptionally strong and tough. We also show that post-drawing steps such as annealing, dehydration and covalent cross-linking can dramatically improve the long-term dimensional stability of the threads. The data presented here suggest that hagfish slime threads are a model that should be pursued in the quest to produce fibres that are ecologically sustainable and economically viable.
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Affiliation(s)
- Douglas S Fudge
- Department of Integrative Biology, University of Guelph, Ontario, Canada.
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Antheraea pernyi silk fiber: a potential resource for artificially biospinning spider dragline silk. J Biomed Biotechnol 2010; 2010:683962. [PMID: 20454537 PMCID: PMC2864894 DOI: 10.1155/2010/683962] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 01/08/2010] [Accepted: 03/01/2010] [Indexed: 11/17/2022] Open
Abstract
The outstanding properties of spider dragline silk are likely to be determined by a combination of the primary sequences and the secondary structure of the silk proteins. Antheraea pernyi silk has more similar sequences to spider dragline silk than the silk from its domestic counterpart, Bombyx mori. This makes it much potential as a resource for biospinning spider dragline silk. This paper further verified its possibility as the resource from the mechanical properties and the structures of the A. pernyi silks prepared by forcible reeling. It is surprising that the stress-strain curves of the A. pernyi fibers show similar sigmoidal shape to those of spider dragline silk. Under a controlled reeling speed of 95 mm/s, the breaking energy was 1.04 x 10(5) J/kg, the tensile strength was 639 MPa and the initial modulus was 9.9 GPa. It should be noted that this breaking energy of the A. pernyi silk approaches that of spider dragline silk. The tensile properties, the optical orientation and the beta-sheet structure contents of the silk fibers are remarkably increased by raising the spinning speeds up to 95 mm/s.
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35
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Reddy N, Yang Y. Morphology and tensile properties of silk fibers produced by uncommon Saturniidae. Int J Biol Macromol 2010; 46:419-24. [DOI: 10.1016/j.ijbiomac.2010.02.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Revised: 02/25/2010] [Accepted: 02/26/2010] [Indexed: 10/19/2022]
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36
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Jenkins JE, Creager MS, Lewis RV, Holland GP, Yarger JL. Quantitative Correlation between the protein primary sequences and secondary structures in spider dragline silks. Biomacromolecules 2010; 11:192-200. [PMID: 20000730 PMCID: PMC2805410 DOI: 10.1021/bm9010672] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Synthetic spider silk holds great potential for use in various applications spanning medical uses to ultra lightweight armor; however, producing synthetic fibers with mechanical properties comparable to natural spider silk has eluded the scientific community. Natural dragline spider silks are commonly made from proteins that contain highly repetitive amino acid motifs, adopting an array of secondary structures. Before further advances can be made in the production of synthetic fibers based on spider silk proteins, it is imperative to know the percentage of each amino acid in the protein that forms a specific secondary structure. Linking these percentages to the primary amino acid sequence of the protein will establish a structural foundation for synthetic silk. In this study, nuclear magnetic resonance (NMR) techniques are used to quantify the percentage of Ala, Gly, and Ser that form both beta-sheet and helical secondary structures. The fraction of these three amino acids and their secondary structure are quantitatively correlated to the primary amino acid sequence for the proteins that comprise major and minor ampullate silk from the Nephila clavipes spider providing a blueprint for synthetic spider silks.
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Affiliation(s)
- Janelle E Jenkins
- Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, Arizona 85287-1604, USA
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Affiliation(s)
- Sungkyun Sohn
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003
| | - Samuel P. Gido
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003
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38
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Grunwald I, Rischka K, Kast SM, Scheibel T, Bargel H. Mimicking biopolymers on a molecular scale: nano(bio)technology based on engineered proteins. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2009; 367:1727-1747. [PMID: 19376768 DOI: 10.1098/rsta.2009.0012] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Proteins are ubiquitous biopolymers that adopt distinct three-dimensional structures and fulfil a multitude of elementary functions in organisms. Recent systematic studies in molecular biology and biotechnology have improved the understanding of basic functional and architectural principles of proteins, making them attractive candidates as concept generators for technological development in material science, particularly in biomedicine and nano(bio)technology. This paper highlights the potential of molecular biomimetics in mimicking high-performance proteins and provides concepts for applications in four case studies, i.e. spider silk, antifreeze proteins, blue mussel adhesive proteins and viral ion channels.
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Affiliation(s)
- Ingo Grunwald
- Department of Adhesive Bonding Technology and Surfaces, Fraunhofer Institute for Manufacturing Technology and Applied Materials Research (IFAM)28359 Bremen, Germany
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Fu C, Shao Z, Fritz V. Animal silks: their structures, properties and artificial production. Chem Commun (Camb) 2009:6515-29. [DOI: 10.1039/b911049f] [Citation(s) in RCA: 191] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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Yang M, Kawamura J, Zhu Z, Yamauchi K, Asakura T. Development of silk-like materials based on Bombyx mori and Nephila clavipes dragline silk fibroins. POLYMER 2009. [DOI: 10.1016/j.polymer.2008.10.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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41
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Inspiration from Natural Silks and Their Proteins. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/s0065-2377(08)00205-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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42
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Römer L, Scheibel T. The elaborate structure of spider silk: structure and function of a natural high performance fiber. Prion 2008; 2:154-61. [PMID: 19221522 DOI: 10.4161/pri.2.4.7490] [Citation(s) in RCA: 175] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Biomaterials, having evolved over millions of years, often exceed man-made materials in their properties. Spider silk is one outstanding fibrous biomaterial which consists almost entirely of large proteins. Silk fibers have tensile strengths comparable to steel and some silks are nearly as elastic as rubber on a weight to weight basis. In combining these two properties, silks reveal a toughness that is two to three times that of synthetic fibers like Nylon or Kevlar. Spider silk is also antimicrobial, hypoallergenic and completely biodegradable. This article focuses on the structure-function relationship of the characterized highly repetitive spider silk spidroins and their conformational conversion from solution into fibers. Such knowedge is of crucial importance to understanding the intrinsic properties of spider silk and to get insight into the sophisticated assembly processes of silk proteins. This review further outlines recent progress in recombinant production of spider silk proteins and their assembly into distinct polymer materials as a basis for novel products.
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Affiliation(s)
- Lin Römer
- Universität Bayreuth, Fakultät für angew. Naturwissenschaften, Lehrstuhl für Biomaterialien, Bayreuth, Germany
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43
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Zhu J, Shao H, Hu X. Morphology and structure of electrospun mats from regenerated silk fibroin aqueous solutions with adjusting pH. Int J Biol Macromol 2007; 41:469-74. [PMID: 17689606 DOI: 10.1016/j.ijbiomac.2007.06.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 06/07/2007] [Accepted: 06/18/2007] [Indexed: 10/23/2022]
Abstract
In this paper, regenerated silk fibroin (SF) aqueous solutions were adjusted to a pH of 6.9 by mimicing the condition in the posterior division of silkworm's gland and rheological behavior of solutions was investigated. The electrospinning technique was used to prepare fibers, and non-woven mats of regenerated B. mori silk fibroin were successfully obtained. The effects of electrospinning parameters on the morphology and diameter of regenerated silk fibers were investigated by orthogonal design. Statistical analysis showed that voltage, the concentration of regenerated SF solutions and the distance between tip and collection plate were the most dominant parameters to fiber morphology, diameter and diameter distribution, respectively. An optimal electrospinning condition was obtained in producing uniform cylindrical fibers with an average diameter of 1300nm. It was as follows: the concentration 30%, voltage 40kV, distance 20cm. The structure of electrospun mats was characterized by Raman spectroscopy (RS), wide-angle X-ray diffraction (WAXD) and modulated differential scanning calorimetry (MDSC). It was found that electrospun mats were predominantly random coil/silk I structure, and the transition to silk II (beta-sheet) rich structure should be further explored.
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Affiliation(s)
- Jingxin Zhu
- State Key Laboratory for modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 200051, PR China
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45
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Zhou L, Chen X, Shao Z, Huang Y, Knight DP. Effect of metallic ions on silk formation in the Mulberry silkworm, Bombyx mori. J Phys Chem B 2007; 109:16937-45. [PMID: 16853155 DOI: 10.1021/jp050883m] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A protein conformation transition from random coil and/or helical conformation to beta-sheet is known to be central to the process used by silk-spinning spiders and insects to convert concentrated protein solutions to tough insoluble threads. Several factors including pH, metallic ions, shear force, and/or elongational flow can initiate this transition in both spiders and silkworms. Here, we report the use of proton induced X-ray emission (PIXE), inductively coupled plasma mass spectroscopy (ICP-MS) and atomic adsorption spectroscopy (AAS) to investigate the concentrations of six metal elements (Na, K, Mg, Ca, Cu, and Zn) at different stages in the silk secretory pathway in the Bombyx mori silkworm. We also report the use of Raman spectra to monitor the effects of these six metallic ions on the conformation transition of natural silk fibroin dope and concentrated regenerated silk fibroin solution at concentrations similar to the natural dope. The results showed that the metal element contents increased from the posterior part to the anterior part of silk gland with the exception of Ca which decreased significantly in the anterior part. We show that these changes in composition can be correlated with (i) the ability of Mg2+, Cu2+, and Zn2+ to induce the conformation transition of silk fibroin to beta-sheet, (ii) the effect of Ca2+ in forming a stable protein network (gel), and (iii) the ability of Na+ and K+ to break down the protein network.
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Affiliation(s)
- Li Zhou
- The Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, National Microanalysis Center, Fudan University, Shanghai, 200433, People's Republic of China
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46
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Drummy LF, Farmer BL, Naik RR. Correlation of the β-sheet crystal size in silk fibers with the protein amino acid sequence. SOFT MATTER 2007; 3:877-882. [PMID: 32900081 DOI: 10.1039/b701220a] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Low voltage transmission electron microscopy (LVTEM) and wide angle X-ray scattering (WAXS) are used to independently determine the size of the β-sheet crystalline regions in Bombyx mori silk fibers. The peak in the size distributions of the major and minor axes of the anisotropic crystallites measured from the LVTEM images compare well with the average sizes as determined by Scherrer analysis of the X-ray fiber diagrams. These values are then discussed in the context of the B. mori fibroin heavy chain amino acid sequence, and the underlying mechanism for the organism's control on fiber crystallite size, and therefore mechanical properties, is proposed.
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Affiliation(s)
| | - B L Farmer
- 3005 Hobson Way, Wright Patterson Air Force Base, OH 45433, USA.
| | - Rajesh R Naik
- 3005 Hobson Way, Wright Patterson Air Force Base, OH 45433, USA.
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47
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Chen X, Shao Z, Knight DP, Vollrath F. Conformation transition kinetics of Bombyx mori silk protein. Proteins 2007; 68:223-31. [PMID: 17436322 DOI: 10.1002/prot.21414] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Time-resolved FTIR analysis was used to monitor the conformation transition induced by treating regenerated Bombyx mori silk fibroin films and solutions with different concentrations of ethanol. The resulting curves showing the kinetics of the transition for both films and fibroin solutions were influenced by the ethanol concentration. In addition, for silk fibroin solutions the protein concentration also had an effect on the kinetics. At low ethanol concentrations (for example, less than 40% v/v in the case of film), films and fibroin solutions showed a phase in which beta-sheets slowly formed at a rate dependent on the ethanol concentration. Reducing the concentration of the fibroin in solutions also slowed the formation of beta-sheets. These observations suggest that this phase represents a nucleation step. Such a nucleation phase was not seen in the conformation transition at ethanol concentrations > 40% in films or > 50% in silk fibroin solutions. Our results indicate that the ethanol-induced conformation transition of silk fibroin in films and solutions is a three-phase process. The first phase is the initiation of beta-sheet structure (nucleation), the second is a fast phase of beta-sheet growth while the third phase represents a slow perfection of previously formed beta-sheet structure. The nucleation step can be very fast or relatively slow, depending on factors that influence protein chain mobility and intermolecular hydrogen bond formation. The findings give support to the previous evidence that natural silk spinning in silkworms is nucleation-dependent, and that silkworms (like spiders) use concentrated silk protein solutions, and careful control of the pH value and metallic ion content of the processing environment to speed up the nucleation step to produce a rapid conformation transition to convert the water soluble spinning dope to a tough solid silk fiber.
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Affiliation(s)
- Xin Chen
- The Key Laboratory of Molecular Engineering of Polymers of MOE, Department of Macromolecular Science, Fudan University, Shanghai 200433, People's Republic of China.
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48
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Stark M, Grip S, Rising A, Hedhammar M, Engström W, Hjälm G, Johansson J. Macroscopic fibers self-assembled from recombinant miniature spider silk proteins. Biomacromolecules 2007; 8:1695-701. [PMID: 17402782 DOI: 10.1021/bm070049y] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Strength, elasticity, and biocompatibility make spider silk an attractive resource for the production of artificial biomaterials. Spider silk proteins, spidroins, contain hundreds of repeated poly alanine/glycine-rich blocks and are difficult to produce recombinantly in soluble form. Most previous attempts to produce artificial spider silk fibers have included solubilization steps in nonphysiological solvents. It is here demonstrated that a miniature spidroin from a protein in dragline silk of Euprosthenops australis can be produced in a soluble form in Escherichia coli when fused to a highly soluble protein partner. Although this miniature spidroin contains only four poly alanine/glycine-rich blocks followed by a C-terminal non-repetitive domain, meter-long fibers are spontaneously formed after proteolytic release of the fusion partner. The structure of the fibers is similar to that of dragline silks, and although self-assembled from recombinant proteins they are as strong as fibers spun from redissolved silk. Moreover, the fibers appear to be biocompatible because human tissue culture cells can grow on and attach to the fibers. These findings enable controlled production of high-performance biofibers at large scale under physiological conditions.
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Affiliation(s)
- Margareta Stark
- Department of Anatomy, Physiology, and Biochemistry, The Biomedical Centre, Swedish University of Agricultural Sciences, SE-751 23 Uppsala, Sweden
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49
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Guan Z. Supramolecular design in biopolymers and biomimetic polymers for advanced mechanical properties. POLYM INT 2007. [DOI: 10.1002/pi.2245] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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50
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Bai J, Ma T, Chu W, Wang R, Silva L, Michal C, Chiao JC, Chiao M. Regenerated spider silk as a new biomaterial for MEMS. Biomed Microdevices 2006; 8:317-23. [PMID: 16927024 DOI: 10.1007/s10544-006-9820-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Spider drag-line silk is introduced for the first time as a new biomaterial for Micro-Electro-Mechanical Systems (MEMS). The tasks accomplished in this paper were focused on mechanical characterization of regenerated spider silk under two conditions: (1) spin-coated thin film formed onto a silicon substrate; and (2) formation of a free-standing microbridge (800 x 800 x 40 microm3) obtained by a surface micromachining process. Micromechanical tests using a nano indentation machine showed the spider silk film having an elastic modulus of 7.3 GPa, a loss tangent of 0.044 and an UTS (Ultimate Tensile Strength) of 85.1 MPa.
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Affiliation(s)
- Jiamei Bai
- Department of Mechanical Engineering, 6250 Applied Science Lane, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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