The crystal structure of silk fibroin

Warwicker, J. O.

doi:10.1107/s0365110x54001867

Cited by 88 publications

(54 citation statements)

References 2 publications

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“…This value is comparable to that presently reported for photonic crystal structures and surface plasmon biosensors (5,25,26). The smallest detection volume of silk protein is estimated as AðtÞðD∕MÞ, where A is the total surface area of the Gaussian prime nanopatterned array (48.2 × 48.2 μm 2 ), t is the film thickness (2 nm), D is the density of the protein (1.4 g∕cm 3 ) (27), and M is the molecular mass of the protein (375 kDa) (28). About 17 atto-mole of protein molecules is estimated in our experiment contributing to the distinctive shift of the spectral peak and the colorimetric pattern change.…”

supporting

confidence: 59%

Spatial and spectral detection of protein monolayers with deterministic aperiodic arrays of metal nanoparticles

Lee

Amsden²,

Boriskina

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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Light scattering phenomena in periodic systems have been investigated for decades in optics and photonics. Their classical description relies on Bragg scattering, which gives rise to constructive interference at specific wavelengths along well defined propagation directions, depending on illumination conditions, structural periodicity, and the refractive index of the surrounding medium. In this paper, by engineering multifrequency colorimetric responses in deterministic aperiodic arrays of nanoparticles, we demonstrate significantly enhanced sensitivity to the presence of a single protein monolayer. These structures, which can be readily fabricated by conventional Electron Beam Lithography, sustain highly complex structural resonances that enable a unique optical sensing approach beyond the traditional Bragg scattering with periodic structures. By combining conventional dark-field scattering micro-spectroscopy and simple image correlation analysis, we experimentally demonstrate that deterministic aperiodic surfaces with engineered structural color are capable of detecting, in the visible spectral range, protein layers with thickness of a few tens of Angstroms.biosensing | colorimetric fingerprint | deterministic aperiodic system | nanophotonics

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supporting

confidence: 59%

Spatial and spectral detection of protein monolayers with deterministic aperiodic arrays of metal nanoparticles

Lee

Amsden²,

Boriskina

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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“…Following this step, some peaks related with interplanar distances of crystalline phases of alanine, glycine, silk peptide and silk fibroin were indicated as observed peaks in the patterns. Table 1 The widely expected crystalline structures in the content of the silk samples and observed peaks (in the hiding silk of Eresus cinnaberinus) related with these structures Alanine [31,36] Glycine [31,36] Silk peptide [5] Silk fibroin [1,42] Crystallographic planes related with widely expected crystalline structures in the content of the silk samples and observed peaks in the hiding silk of Eresus cinnaberinus were given in the Table 1. Some of the XRD patterns are given in Fig.…”

Section: Silk Samplingmentioning

confidence: 99%

Structural characterization of a variety of spider silks from Turkey using different biophysical techniques

et al. 2011

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Abstract. Various experimental methods (XRD, FTIR, SAXS, DLS and SEM) were used to investigate structures of the silk samples weaved by spiders in Turkey. Silk samples were collected from the natural habitats belonging to the spider species (i.e., Near Salt Lake/Şereflikoçhisar,İvriz Dam/Eregli-Konya, Karataş Lake/Burdur and several locations in Black Sea Region of Turkey). Among all collected species, Araneidae (Araneus angulatus, Argiope bruennichi, Argiope lobata, Larinoides cornutus), Eresidae (Eresus cinnaberinus), Agelenidae (Agelena labyrinthica), Oecobidae (Uroctea durandi), Miturgidae (Cheiracanthium erraticum), Salticidae (Heliophanus flavipes, Philaeus chrysops), Theridiidae (Steatoda paykulliana) and Gnaphosidae were found significant amongst other spider species. Structural differences and similarities of these species were reported. Diameter range of draglines, inter crystallite distance of nano-size structures, mean size range of nano-structure aggregations, crystallite size range, information about protein content were obtained. The mechanical properties of some silk fibers were also investigated.

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“…Fiber diffraction patterns were recorded on a two-dimensional CCD detector. The lattice strain of the -sheet fibroin crystals in the direction of the tensile stress was determined from the shift of the radial position of the 002 reflection [4,9,20].…”

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confidence: 99%

Mechanical Properties of Silk: Interplay of Deformation on Macroscopic and Molecular Length Scales

et al. 2008

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Using an in situ combination of tensile tests and x-ray diffraction, we have determined the mechanical properties of both the crystalline and the disordered phase of the biological nanocomposite silk by adapting a model from linear viscoelastic theory to the semicrystalline morphology of silk. We observe a strong interplay between morphology and mechanical properties. Silk's high extensibility results principally from the disordered phase; however, the crystals are also elastically deformed. DOI: 10.1103/PhysRevLett.100.048104 PACS numbers: 87.85.Jÿ, 61.05.cp, 81.70.Bt, 87.15.La Natural silks exhibit extraordinary mechanical properties, combining high tensile strength with a high elongation at failure. Producing man-made fibers with such properties requires a considerable input of energy compared to natural silk fibers spun from aqueous protein solution at ambient temperature. The toughest silk known is spun by spiders. However, it has recently been shown that, chemically and rheologically closely related, silkworm silk [1] could reach comparable parameters in an optimized spinning process [2].The similarity between spider and silkworm silk fibers extends to their morphology. Both are semicrystalline nanocomposites, with ordered regions (-sheet protein nanocrystals) embedded in a softer matrix of disordered material (spider silk, [3]; silkworm fibroin, [4]). Tensile deformation of silk fibers involves a strong contribution of viscoelastic material, presumably in the disordered regions [5]. However, detailed information on the relaxation mechanism is still missing.The mesoscopic structure of polymer nanocomposites is the key to their mechanical properties [6]. Mimicking nature's spinning process to produce artificial fibers with optimized morphology and, thus, optimal mechanical performance either from silkworm or recombinant spider silk spinning dope [7] would be highly desirable. The models of silk available today do not directly connect structure and macroscopic properties. Termonia's model [8] describes silk as a hydrogen-bonded rubberlike matrix with embedded stiff crystals serving as cross-link sites. At their surface, another ordered phase of protein molecules is required in order to explain the static mechanical properties. The assumed high rigidity of the -sheet crystals has been questioned by x-ray diffraction results [9]. While the recent model by Porter et al. [10] and Vollrath and Porter [11] includes morphological parameters such as ordered/ disordered fractions, which are very difficult to obtain experimentally, deformation processes in crystals and matrix are neglected. A molecular model for spider capture silk is available but restricted to this very specialized silk type [12].The aim of this Letter is to establish a model for silk incorporating the macroscopic mechanical behavior, in particular, viscoelasticity, on the basis of its semicrystalline morphology. To this end, we combined high-resolution cyclic stress-strain measurements of single silkworm silk fibers (such as reported in [13][14...

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The crystal structure of silk fibroin

Cited by 88 publications

References 2 publications

Spatial and spectral detection of protein monolayers with deterministic aperiodic arrays of metal nanoparticles

Spatial and spectral detection of protein monolayers with deterministic aperiodic arrays of metal nanoparticles

Structural characterization of a variety of spider silks from Turkey using different biophysical techniques

Mechanical Properties of Silk: Interplay of Deformation on Macroscopic and Molecular Length Scales

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