scholarly journals Synthetic Spider Silk Provides New Insights into the Mechanisms of Flagelliform Silk Fiber Assemble and Elastomeric Behavior

2020 ◽  
Author(s):  
Daniela Bittencourt ◽  
Paula F. Oliveira ◽  
Betulia M. Souto ◽  
Sonia Maria de Freitas ◽  
Valquiria Michalczechen-Lacerda ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Recombinant Proteins ◽  
Spider Silk ◽  
Structural Data ◽  
Fiber Formation ◽  
Published Data ◽  
Silk Proteins ◽  
Charged Amino Acids ◽  
Spider Silks ◽  
The Relationship

<p>In order to better understand the relationship between the elastomeric behavior of Flagelliform (Flag) spider silks and its molecular structure, it was designed and produced the <i>Nephilengys cruentata</i> Flageliform (Flag) spidroin analogue rNcFlag2222. The recombinant proteins are composed by the elastic repetitive glycine-rich motifs (GPGGX/GGX) and the spacer region, rich in hydrophilic charged amino acids, present at the native silk spidroin. Using different approaches for nanomolecular protein analysis, the structural data of rNcFlag2222 recombinant proteins were compared in its fibrillar and in its fully solvated states. Based on the results and previous published data, it was possible to propose a model for the molecular dynamics of Flag spidroins’ repetitive core, during gland storage and fiber formation, and their contribution to its exceptional mechanoelastic properties. This model assumes that the Flag silk proteins acquire elastomeric behavior through a mechanism similar to collagen proteins, with the repetitive glycine-rich and the spacer regions, together with water, playing important roles in fiber assemble and elastomeric behavior.</p>

scholarly journals Synthetic Spider Silk Provides New Insights into the Mechanisms of Flagelliform Silk Fiber Assemble and Elastomeric Behavior

2020 ◽  
Author(s):  
Daniela Bittencourt ◽  
Paula F. Oliveira ◽  
Betulia M. Souto ◽  
Sonia Maria de Freitas ◽  
Valquiria Michalczechen-Lacerda ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Recombinant Proteins ◽  
Spider Silk ◽  
Structural Data ◽  
Fiber Formation ◽  
Published Data ◽  
Silk Proteins ◽  
Charged Amino Acids ◽  
Spider Silks ◽  
The Relationship

<p>In order to better understand the relationship between the elastomeric behavior of Flagelliform (Flag) spider silks and its molecular structure, it was designed and produced the <i>Nephilengys cruentata</i> Flageliform (Flag) spidroin analogue rNcFlag2222. The recombinant proteins are composed by the elastic repetitive glycine-rich motifs (GPGGX/GGX) and the spacer region, rich in hydrophilic charged amino acids, present at the native silk spidroin. Using different approaches for nanomolecular protein analysis, the structural data of rNcFlag2222 recombinant proteins were compared in its fibrillar and in its fully solvated states. Based on the results and previous published data, it was possible to propose a model for the molecular dynamics of Flag spidroins’ repetitive core, during gland storage and fiber formation, and their contribution to its exceptional mechanoelastic properties. This model assumes that the Flag silk proteins acquire elastomeric behavior through a mechanism similar to collagen proteins, with the repetitive glycine-rich and the spacer regions, together with water, playing important roles in fiber assemble and elastomeric behavior.</p>

scholarly journals Hierarchical spidroin micellar nanoparticles as the fundamental precursors of spider silks

2018 ◽  
Vol 115 (45) ◽  
pp. 11507-11512 ◽  
Author(s):  
Lucas R. Parent ◽  
David Onofrei ◽  
Dian Xu ◽  
Dillan Stengel ◽  
John D. Roehling ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Spider Silk ◽  
Fiber Spinning ◽  
Fiber Formation ◽  
Natural Material ◽  
Physical Form ◽  
Spinning Process ◽  
Black Widow Spiders ◽  
Spider Silks

Many natural silks produced by spiders and insects are unique materials in their exceptional toughness and tensile strength, while being lightweight and biodegradable–properties that are currently unparalleled in synthetic materials. Myriad approaches have been attempted to prepare artificial silks from recombinant spider silk spidroins but have each failed to achieve the advantageous properties of the natural material. This is because of an incomplete understanding of the in vivo spidroin-to-fiber spinning process and, particularly, because of a lack of knowledge of the true morphological nature of spidroin nanostructures in the precursor dope solution and the mechanisms by which these nanostructures transform into micrometer-scale silk fibers. Herein we determine the physical form of the natural spidroin precursor nanostructures stored within spider glands that seed the formation of their silks and reveal the fundamental structural transformations that occur during the initial stages of extrusion en route to fiber formation. Using a combination of solution phase diffusion NMR and cryogenic transmission electron microscopy (cryo-TEM), we reveal direct evidence that the concentrated spidroin proteins are stored in the silk glands of black widow spiders as complex, hierarchical nanoassemblies (∼300 nm diameter) that are composed of micellar subdomains, substructures that themselves are engaged in the initial nanoscale transformations that occur in response to shear. We find that the established micelle theory of silk fiber precursor storage is incomplete and that the first steps toward liquid crystalline organization during silk spinning involve the fibrillization of nanoscale hierarchical micelle subdomains.

scholarly journals Expanding Canonical Spider Silk Properties through a DNA Combinatorial Approach

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3596
Author(s):  
Zaroug Jaleel ◽  
Shun Zhou ◽  
Zaira Martín-Moldes ◽  
Lauren M. Baugh ◽  
Jonathan Yeh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Recombinant Proteins ◽  
Elastic Moduli ◽  
Spider Silk ◽  
Building Blocks ◽  
Random Coil ◽  
Infrared Spectrometry ◽  
Silk Proteins ◽  
Dragline Silk ◽  
Latrodectus Hesperus

The properties of native spider silk vary within and across species due to the presence of different genes containing conserved repetitive core domains encoding a variety of silk proteins. Previous studies seeking to understand the function and material properties of these domains focused primarily on the analysis of dragline silk proteins, MaSp1 and MaSp2. Our work seeks to broaden the mechanical properties of silk-based biomaterials by establishing two libraries containing genes from the repetitive core region of the native Latrodectus hesperus silk genome (Library A: genes masp1, masp2, tusp1, acsp1; Library B: genes acsp1, pysp1, misp1, flag). The expressed and purified proteins were analyzed through Fourier Transform Infrared Spectrometry (FTIR). Some of these new proteins revealed a higher portion of β-sheet content in recombinant proteins produced from gene constructs containing a combination of masp1/masp2 and acsp1/tusp1 genes than recombinant proteins which consisted solely of dragline silk genes (Library A). A higher portion of β-turn and random coil content was identified in recombinant proteins from pysp1 and flag genes (Library B). Mechanical characterization of selected proteins purified from Library A and Library B formed into films was assessed by Atomic Force Microscopy (AFM) and suggested Library A recombinant proteins had higher elastic moduli when compared to Library B recombinant proteins. Both libraries had higher elastic moduli when compared to native spider silk proteins. The preliminary approach demonstrated here suggests that repetitive core regions of the aforementioned genes can be used as building blocks for new silk-based biomaterials with varying mechanical properties.

Critical role of minor eggcase silk component in promoting spidroin chain alignment and strong fiber formation

2021 ◽  
Vol 118 (38) ◽  
pp. e2100496118
Author(s):  
Tiantian Fan ◽  
Ruiqi Qin ◽  
Yan Zhang ◽  
Jingxia Wang ◽  
Jing-Song Fan ◽  
...  
Keyword(s):  
Self Assembly ◽  
Spider Silk ◽  
Critical Role ◽  
Minor Component ◽  
Fiber Formation ◽  
Repetitive Domain ◽  
Chain Alignment ◽  
Main Components ◽  
Spider Silks

Natural spider silk with extraordinary mechanical properties is typically spun from more than one type of spidroin. Although the main components of various spider silks have been widely studied, little is known about the molecular role of the minor silk components in spidroin self-assembly and fiber formation. Here, we show that the minor component of spider eggcase silk, TuSp2, not only accelerates self-assembly but remarkably promotes molecular chain alignment of spidroins upon physical shearing. NMR structure of the repetitive domain of TuSp2 reveals that its dimeric structure with unique charged surface serves as a platform to recruit different domains of the main eggcase component TuSp1. Artificial fiber spun from the complex between TuSp1 and TuSp2 minispidroins exhibits considerably higher strength and Young’s modulus than its native counterpart. These results create a framework for rationally designing silk biomaterials based on distinct roles of silk components.

scholarly journals Meta-analysis reveals materiomic relationships in major ampullate silk across the spider phylogeny

2020 ◽  
Vol 17 (170) ◽  
pp. 20200471 ◽  
Author(s):  
Hamish C. Craig ◽  
Dakota Piorkowski ◽  
Shinichi Nakagawa ◽  
Michael M. Kasumovic ◽  
Sean J. Blamires
Keyword(s):  
Amino Acids ◽  
Spider Silk ◽  
Meta Analysis ◽  
Comparative Methods ◽  
Ultimate Strain ◽  
Phylogenetic Comparative Methods ◽  
Silk Proteins ◽  
Spider Species ◽  
Amino Terminal ◽  
The Relationship

Spider major ampullate (MA) silk, with its combination of strength and extensibility, outperforms any synthetic equivalents. There is thus much interest in understanding its underlying materiome. While the expression of the different silk proteins (spidroins) appears an integral component of silk performance, our understanding of the nature of the relationship between the spidroins, their constituent amino acids and MA silk mechanics is ambiguous. To provide clarity on these relationships across spider species, we performed a meta-analysis using phylogenetic comparative methods. These showed that glycine and proline, both of which are indicators of differential spidroin expression, had effects on MA silk mechanics across the phylogeny. We also found serine to correlate with silk mechanics, probably via its presence within the carboxyl and amino-terminal domains of the spidroins. From our analyses, we concluded that the spidroin expression shifts across the phylogeny from predominantly MaSp1 in the MA silks of ancestral spiders to predominantly MaSp2 in the more derived spiders' silks. This trend was accompanied by an enhanced ultimate strain and decreased Young's modulus in the silks. Our meta-analysis enabled us to decipher between real and apparent influences on MA silk properties, providing significant insights into spider silk and web coevolution and enhancing our capacity to create spider silk-like materials.

Probing the Mysteries of Spider Silk’s Uncharacteristically High Thermal Diffusivity

2013 ◽  
Author(s):  
Troy Munro ◽  
Changhu Xing ◽  
Heng Ban ◽  
Cameron Copeland ◽  
Randolph Lewis
Keyword(s):  
Thermal Properties ◽  
Protein Content ◽  
Spider Silk ◽  
Gold Film ◽  
Milk Proteins ◽  
Initial Study ◽  
Silk Proteins ◽  
Fundamental Understanding ◽  
High Thermal Diffusivity ◽  
Spider Silks

Spider silks exhibit excellent strength, stiffness, and toughness simultaneously, a feat unachievable in most synthetic, structural materials. It has recently been reported that the thermal conductivity of dragline silk is comparable to copper, which is uncharacteristically high for a biomaterial. In order to develop a fundamental understanding of the high thermal properties of spider silk, further research must be made to explore how the structure and organization of spider silk proteins affects heat transfer characteristics. Synthetically produced silks created from spider silk proteins obtained from transgenic sources can be used to determine these protein structure effects by varying protein content and process treatments. This initial study determined the thermal properties of synthetic spider silk created from transgenic goat’s milk proteins using the transient electrothermal method (TET). Results show that the thermal properties of the synthetic silk are lower than the natural spider silk but vary based on the process treatment, and that the annealing of the gold film coated on the fiber has no effect on the measured thermal properties. These results provide a framework for further research on the protein content effect and its role in thermal properties.

Spider Silks: An Overview of Their Component Proteins for Hydrophobicity and Biomedical Applications

2020 ◽  
Vol 27 ◽  
Author(s):  
Fan Li ◽  
Chao Bian ◽  
Daiqin Li ◽  
Qiong Shi
Keyword(s):  
Biomedical Applications ◽  
Spider Silk ◽  
Leading Edge ◽  
Structure Evolution ◽  
Silk Proteins ◽  
Large Molecules ◽  
Wide Range ◽  
Silk Glands ◽  
Potential Applications ◽  
Spider Silks

: Spider silks have received extensive attention from scientists and industries around the world because of their remarkable mechanical properties, which include high tensile strength and extensibility. It is a leading-edge biomaterial resource, with a wide range of potential applications. Spider silks are composed of silk proteins, which are usually very large molecules, yet many silk proteins still remain largely underexplored. While there are numerous reviews on spider silks from diverse perspectives, here we provide a most up-to-date overview of the spider silk component protein family in terms of its molecular structure, evolution, hydrophobicity, and biomedical applications. Given the confusion regarding spidroin naming, we emphasize the need for coherent and consistent nomenclature for spidroins and provide recommendations for preexisting spidroin names that are inconsistent with nomenclature. We then review recent advances in the components, identification, and structures of spidroin genes. We next discuss the hydrophobicity of spidroins, with particular attention on the unique aquatic spider silks. Aquatic spider silks are less known but may inspire innovation in biomaterials. Furthermore, we provide new insights into antimicrobial peptides from spider silk glands. Finally, we present possibilities for future uses of spider silks.

scholarly journals Structural Basis of Oligomerization of N-Terminal Domain of Spider Aciniform Silk Protein

2020 ◽  
Vol 21 (12) ◽  
pp. 4466 ◽  
Author(s):  
Rusha Chakraborty ◽  
Jing-song Fan ◽  
Chong Cheong Lai ◽  
Palur Venkata Raghuvamsi ◽  
Pin Xuan Chee ◽  
...  
Keyword(s):  
Spider Silk ◽  
Homology Modelling ◽  
Fiber Formation ◽  
Water Soluble ◽  
Silk Protein ◽  
Structural Basis ◽  
Formation Mechanisms ◽  
Resonance Spectroscopy ◽  
Silk Proteins ◽  
Terminal Domains

Spider silk is self-assembled from water-soluble silk proteins through changes in the environment, including pH, salt concentrations, and shear force. The N-terminal domains of major and minor ampullate silk proteins have been found to play an important role in the assembly process through salt- and pH-dependent dimerization. Here, we identified the sequences of the N-terminal domains of aciniform silk protein (AcSpN) and major ampullate silk protein (MaSpN) from Nephila antipodiana (NA). Different from MaSpN, our biophysical characterization indicated that AcSpN assembles to form large oligomers, instead of a dimer, upon condition changes from neutral to acidic pH and/or from a high to low salt concentration. Our structural studies, by nuclear magnetic resonance spectroscopy and homology modelling, revealed that AcSpN and MaSpN monomers adopt similar overall structures, but have very different charge distributions contributing to the differential self-association features. The intermolecular interaction interfaces for AcSp oligomers were identified using hydrogen–deuterium exchange mass spectrometry and mutagenesis. On the basis of the monomeric structure and identified interfaces, the oligomeric structures of AcSpN were modelled. The structural information obtained will facilitate an understanding of silk fiber formation mechanisms for aciniform silk protein.

The Effect of Donor Molecular Structure on Power Conversion Efficiency of Small-Molecule-Based Organic Solar Cells

2019 ◽  
Vol 16 (3) ◽  
pp. 236-243 ◽  
Author(s):  
Hui Zhang ◽  
Yibing Ma ◽  
Youyi Sun ◽  
Jialei Liu ◽  
Yaqing Liu ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Solar Cells ◽  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Small Molecule ◽  
Organic Solar Cells ◽  
Molecular Design ◽  
Power Conversion ◽  
The Relationship

In this review, small-molecule donors for application in organic solar cells reported in the last three years are highlighted. Especially, the effect of donor molecular structure on power conversion efficiency of organic solar cells is reported in detail. Furthermore, the mechanism is proposed and discussed for explaining the relationship between structure and power conversion efficiency. These results and discussions draw some rules for rational donor molecular design, which is very important for further improving the power conversion efficiency of organic solar cells based on the small-molecule donor.

scholarly journals Intraspecific Latitudinal Variation in Nest Orientation Among Ground-Nesting Passerines: A Study Using Published Data

The Condor ◽  
2007 ◽  
Vol 109 (2) ◽  
pp. 441-446 ◽  
Author(s):  
Niall H.K. Burton
Keyword(s):  
Early Morning ◽  
Published Data ◽  
Nest Entrance ◽  
Clear Trend ◽  
European Species ◽  
Statistical Comparison ◽  
Species Comparisons ◽  
Nest Microclimate ◽  
The Relationship ◽  
Ground Nesting

Abstract The relationship between nest entrance orientation and latitude among ground-nesting passerines was reviewed using published information. Data were collated for seven North American and European species. Pooling within-species comparisons, there was a clear trend from a preference for north-facing nests at lower latitudes to eastward- or southward-facing nests farther north. Orientations differed significantly in eight of 12 cases for which statistical comparison was possible, means differing in the expected direction in six of these cases. These results highlight how the influence of solar radiation on nest microclimate typically delineates preferred nest orientation in these species, i.e., at lower latitudes, the need for shade results in a preference for northward orientations; at mid latitudes, eastward orientations predominate, reflecting a probable balance between the benefits of warmth in the early morning and shade in the afternoon; while at high latitudes, nests may be oriented southward to gain warmth throughout the day.

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