Hypotheses that correlate the sequence, structure, and mechanical properties of spider silk proteins

Hayashi, Cheryl Y.; Shipley, Nichola H.; Lewis, Randolph V.

doi:10.1016/s0141-8130(98)00089-0

Cited by 549 publications

(608 citation statements)

References 17 publications

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“…Taking into consideration that repetitive amino acid sequences are unlikely to adopt an ideal random conformation without any (at least locally) regular structure,45 it would be plausible that PAS polypeptides show a kind of random‐coil structure influenced by the PPII conformation 46. Of note, it has been proposed that the PPII conformation represents the energetically most favored conformation of the peptide bond,47 since solvation of the hydrophilic polypeptide backbone is maximized while putative entropy loss due to formation of secondary structure with more pronounced order (such as α‐helix) is kept minimal.…”

Section: Resultsmentioning

confidence: 99%

The polypeptide biophysics of proline/alanine‐rich sequences (PAS): Recombinant biopolymers with PEG‐like properties

Breibeck

Skerra

2017

Biopolymers

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PAS polypeptides comprise long repetitive sequences of the small L‐amino acids proline, alanine and/or serine that were developed to expand the hydrodynamic volume of conjugated pharmaceuticals and prolong their plasma half‐life by retarding kidney filtration. Here, we have characterized the polymer properties both of the free polypeptides and in fusion with the biopharmaceutical IL‐1Ra. Data from size exclusion chromatography, dynamic light scattering, circular dichroism spectroscopy and quantification of hydrodynamic and polar properties demonstrate that the biosynthetic PAS polypeptides exhibit random coil behavior in aqueous solution astonishingly similar to the chemical polymer poly‐ethylene glycol (PEG). The solvent‐exposed PAS peptide groups, in the absence of secondary structure, account for strong hydrophilicity, with negligible contribution by the Ser side chains. Notably, PAS polypeptides exceed PEG of comparable molecular mass in hydrophilicity and hydrodynamic volume while exhibiting lower viscosity. Their uniform monodisperse composition as genetically encoded polymers and their biological nature, offering biodegradability, render PAS polypeptides a promising PEG mimetic for biopharmaceutical applications.

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Section: Resultsmentioning

confidence: 99%

The polypeptide biophysics of proline/alanine‐rich sequences (PAS): Recombinant biopolymers with PEG‐like properties

Breibeck

Skerra

2017

Biopolymers

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“…To assign correspondence between our N. clavipes spidroins and those previously described, we performed alignments of conserved N-and C-terminal sequences and internal motifs reported to be specific to a particular spidroin class [43][44][45] . Most of our N. clavipes Fig.…”

Section: An Annotated Genome For N Clavipesmentioning

confidence: 99%

The Nephila clavipes genome highlights the diversity of spider silk genes and their complex expression

et al. 2017

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More than 380 million years of evolution have produced >46,000 extant spider species, exhibiting an incredible diversity of silks used for prey capture and reproduction [1][2][3] . Spider silks can be stronger than steel and tougher than Kevlar, yet are much lighter weight than these manmade materials 4 . Silks vary in extensibility 5 , are temperature resilient 6 , can enable electrical conduction 7 , and can inhibit bacterial growth while being nearly invisible to the human immune system 8 . Thus, novel materials derived from spider silks offer tremendous potential for medical and industrial innovation. To take advantage of their desirable properties, we must learn more about spider silk genetic structure, functional diversity, and production.A female orb-weaving spider can have up to seven morphologically differentiated types of silk glands, each believed to extrude a distinct class of silk with biophysical characteristics resulting from the expression of a unique combination of silk genes in that gland 9,10 . The silk classes of a typical 'gluey silk' orb-weaver (Araneoidea) female include (i) major ampullate silk, which exhibits great tensile strength and is employed in draglines, bridgelines, and web radii 11,12 ; (ii) minor ampullate silk, used for inelastic temporary spirals during web building 11,12 ; (iii) cement-like piriform silk that bonds fibers together and to other substrates 13,14 ; (iv) strong, yet flexible aciniform silk used for prey wrapping and egg case insulation 15 ; (v) tubuliform and cylindriform silk that constitutes the tough outer layer of egg cases 16,17 ; (vi) flagelliform silk that exhibits unparalleled extensibility and is used in the capture spiral 18,19 ; and (vii) the viscous and sticky aggregate silk that aids in prey capture [20][21][22][23][24] . Many spider species produce just a subset of these silk classes, and some produce yet other silk types, including cribellate silk 25 . Each species possesses an assortment of specialized gland types that are thought to produce distinct classes of silks to fit specific needs 9,26,27 .Spider silks are composed primarily of spidroin proteins (where a 'spidroin' is a spider fibroin [28][29][30][31] ) that, by convention, have been named and classified according to the specific silk gland in which they were first discovered. Spidroin proteins have conserved N-and C-terminal domains that flank long runs of repeated motifs 32-34 , the composition and number of which confer specific physical properties to silks 27 . Yet, despite decades of research on orb-weaver silks, there is incomplete knowledge of all the spidroins within an orb-weaver species.Adding to the sampling of sequences obtained from targeted investigations, the assembly of the velvet spider (Stegodyphus mimosarum) genome yielded 19 spidroins, the largest collection from any single species 27 . Owing to the challenges of assembling arrays of repeats, several of the S. mimosarum spidroin sequences are incomplete, without the sequences encoding N-and C-terminal domains anchored ...

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“…1a) [6][7][8]. Thereby, the anti-parallel beta-sheet nanocrystals [9][10][11][12] play a key role in defining the mechanical properties as they provide stiff orderly cross-linking domains embedded in a semiamorphous matrix that consists of less orderly beta-structures, 3 1 helices and beta-turns [6,13,14].…”

Section: Introductionmentioning

confidence: 99%

“…Similar to their role in other mechanical proteins [15][16][17][18][19][20][21], it has been hypothesized that H-bond arrays in beta-sheet nanocrystals reinforce the polymeric network under mechanical stretch, by forming interlocking regions that transfer the load between chains [13,22]. In particular, Termonia's pioneering empirical two-phase model based on experimental data has been instrumental in explaining the importance of the ratio and size of crystalline and semi-amorphous domains, at a time when large-scale atomistic simulations of spider silk constituents were impossible due to the lack of suitable force fields and computational resources [22].…”

Section: Introductionmentioning

confidence: 99%

Molecular and Nanostructural Mechanisms of Deformation, Strength and Toughness of Spider Silk Fibrils

Keten²,

et al. 2010

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Hypotheses that correlate the sequence, structure, and mechanical properties of spider silk proteins

Cited by 549 publications

References 17 publications

The polypeptide biophysics of proline/alanine‐rich sequences (PAS): Recombinant biopolymers with PEG‐like properties

The polypeptide biophysics of proline/alanine‐rich sequences (PAS): Recombinant biopolymers with PEG‐like properties

The Nephila clavipes genome highlights the diversity of spider silk genes and their complex expression

Molecular and Nanostructural Mechanisms of Deformation, Strength and Toughness of Spider Silk Fibrils

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