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Spider dragline silk

molecular properties and recombinant expression

Rising, Anna (2007). Spider dragline silk. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2007:38
ISBN 978-91-576-7337-4
[Doctoral thesis]

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Abstract

Spider dragline silk possesses several desirable features of a biomaterial; it has extraordinary mechanical properties, is biocompatible and biodegradable. It consists of large proteins, major ampullate spidroins (MaSp:s), that contain alternating polyalanine- and glycine-rich blocks between non-repetitive C- and N-terminal domains. No full length MaSp gene has been cloned, hence the knowledge of their constitution is limited. The spider stores the silk in a liquid form, which is converted into a fibre by a poorly understood mechanism. Even truncated spidroins are difficult to produce recombinantly in soluble form. Most previous attempts to produce artificial spider silk fibres have included solubilization steps in non-physiological solvents and the use of spinning devises for fibre formation. This thesis presents a novel method for production of macroscopic fibres under physiological conditions, without using denaturing agents. A miniature spidroin is identified that can be produced recombinantly in E. coli when fused to a soluble fusion tag. Upon enzymatic release of the fusion tag, the miniature spidroins spontaneously form macroscopic fibres in physiological solution. These fibres resemble native silk and their strength equals that of fibres spun from regenerated silk. Initial studies suggest that the fibres are biocompatible. This represents a major breakthrough for future biomaterial development. Molecular studies of cDNA and genetic sequences encoding the dragline silk revealed an unexpectedly high level of heterogeneity and the presence of at least two MaSp1 genes. Furthermore, the E. australis MaSp2 was characterised for the first time, as well as a new MaSp-like spidroin. Sequence analysis of previously published spidroin N-terminal domains compared with that of E. australis MaSp1, enabled identification of signal peptides and a ∼130 residue non-repetitive domain common to dragline, flagelliform and cylindriform spidroins. Moreover, this highly conserved N-terminal domain was concluded to consist of five positionally conserved α-helices. Structural studies using circular dichroism spectroscopy on recombinantly produced MaSp1 N- and C-terminal domains showed that these are folded, stable and soluble and that salts or pH has no major effect on their secondary structures.

Authors/Creators:Rising, Anna
Title:Spider dragline silk
Subtitle:molecular properties and recombinant expression
Year of publishing :April 2007
Volume:2007:38
Number of Pages:52
Papers/manuscripts:
NumberReferences
ALLI. Stark M., Grip S.*, Rising, A.*, Hedhammar M., Engström W., Hjälm G., Johansson J. (2007) Macroscopic fibres self-assembled from recombinant miniature spider silk proteins. Biomacromolecules, (In press). * Equal contribution II. Rising A., Johansson J., Larson G., Bongcam-Rudloff E., Engström W., Hjälm G. (2007) Major ampullate spidroins from Euprosthenops australis: multiplicity at protein, mRNA and gene levels. (Submitted). III. Rising A., Hjälm G., Engström W., Johansson J. (2006) N-terminal nonrepetitive domain common to dragline, flagelliform, and cylindriform spider silk proteins. Biomacromolecules, 7, 3120-3124. IV. Stark M., Rising A., Grip S., Nordling K., Johansson J., Hedhammar M. (2007) Structural properties of non-repetitive and repetitive parts of major ampullate spidroin 1 from Euprosthenops australis. Implications for fibre formation. (Manuscript).
Place of Publication:Uppsala
ISBN for printed version:978-91-576-7337-4
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:escherichia coli, araneae, silk, animal fibres, proteins, genes, dna, nucleotide sequence, messenger rna, analytical methods
Keywords:Spider, Major ampullate spidroin, Euprosthenops australis, dragline, silk, recombinant production
URN:NBN:urn:nbn:se:slu:epsilon-1545
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-1545
ID Code:1380
Department:(VH) > Dept. of Biomedical Sciences and Veterinary Public Health
Deposited By: Anna Rising
Deposited On:25 Apr 2007 00:00
Metadata Last Modified:02 Dec 2014 10:11

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