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Evidence of Decoupling Protein Structure from Spidroin Expression in Spider Dragline Silks.
Int J Mol Sci 2016; 17(8)IJ

Abstract

The exceptional strength and extensibility of spider dragline silk have been thought to be facilitated by two spidroins, major ampullate spidroin 1 (MaSp1) and major ampullate spidroin 2 (MaSp2), under the assumption that protein secondary structures are coupled with the expressed spidroins. We tested this assumption for the dragline silk of three co-existing Australian spiders, Argiope keyserlingi, Latrodectus hasselti and Nephila plumipes. We found that silk amino acid compositions did not differ among spiders collected in May. We extended these analyses temporally and found the amino acid compositions of A. keyserlingi silks to differ when collected in May compared to November, while those of L. hasselti did not. To ascertain whether their secondary structures were decoupled from spidroin expression, we performed solid-state nuclear magnetic resonance spectroscopy (NMR) analysis on the silks of all spiders collected in May. We found the distribution of alanine toward β-sheet and 3,10helix/random coil conformations differed between species, as did their relative crystallinities, with A. keyserlingi having the greatest 3,10helix/random coil composition and N. plumipes the greatest crystallinity. The protein secondary structures correlated with the mechanical properties for each of the silks better than the amino acid compositions. Our findings suggested that a differential distribution of alanine during spinning could decouple secondary structures from spidroin expression ensuring that silks of desirable mechanical properties are consistently produced. Alternative explanations include the possibility that other spidroins were incorporated into some silks.

Authors+Show Affiliations

Evolution & Ecology Research Centre, School of Biological, Earth & Environmental Sciences, University of New South Wales, Sydney 2052, Australia. s.blamires@unsw.edu.au.Evolution & Ecology Research Centre, School of Biological, Earth & Environmental Sciences, University of New South Wales, Sydney 2052, Australia. m.kasumovic@unsw.edu.au.Department of Life Science, Tunghai University, Taichung 40704, Taiwan. spider@thu.edu.tw.Graduate School of Biomedical Engineering, University of New South Wales, Sydney 2052, Australia. p.martens@unsw.edu.au.NMR Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney 2052, Australia. j.hook@unsw.edu.au.NMR Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney 2052, Australia. a.rawal@unsw.edu.au.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

27517909

Citation

Blamires, Sean J., et al. "Evidence of Decoupling Protein Structure From Spidroin Expression in Spider Dragline Silks." International Journal of Molecular Sciences, vol. 17, no. 8, 2016.
Blamires SJ, Kasumovic MM, Tso IM, et al. Evidence of Decoupling Protein Structure from Spidroin Expression in Spider Dragline Silks. Int J Mol Sci. 2016;17(8).
Blamires, S. J., Kasumovic, M. M., Tso, I. M., Martens, P. J., Hook, J. M., & Rawal, A. (2016). Evidence of Decoupling Protein Structure from Spidroin Expression in Spider Dragline Silks. International Journal of Molecular Sciences, 17(8), doi:10.3390/ijms17081294.
Blamires SJ, et al. Evidence of Decoupling Protein Structure From Spidroin Expression in Spider Dragline Silks. Int J Mol Sci. 2016 Aug 9;17(8) PubMed PMID: 27517909.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Evidence of Decoupling Protein Structure from Spidroin Expression in Spider Dragline Silks. AU - Blamires,Sean J, AU - Kasumovic,Michael M, AU - Tso,I-Min, AU - Martens,Penny J, AU - Hook,James M, AU - Rawal,Aditya, Y1 - 2016/08/09/ PY - 2016/06/30/received PY - 2016/07/28/revised PY - 2016/08/01/accepted PY - 2016/8/13/entrez PY - 2016/8/16/pubmed PY - 2017/5/2/medline KW - amino acids KW - high performance liquid chromatography KW - mechanical properties KW - orb weaving spiders KW - protein secondary structures KW - silk spinning KW - solid-state nuclear magnetic resonance spectroscopy JF - International journal of molecular sciences JO - Int J Mol Sci VL - 17 IS - 8 N2 - The exceptional strength and extensibility of spider dragline silk have been thought to be facilitated by two spidroins, major ampullate spidroin 1 (MaSp1) and major ampullate spidroin 2 (MaSp2), under the assumption that protein secondary structures are coupled with the expressed spidroins. We tested this assumption for the dragline silk of three co-existing Australian spiders, Argiope keyserlingi, Latrodectus hasselti and Nephila plumipes. We found that silk amino acid compositions did not differ among spiders collected in May. We extended these analyses temporally and found the amino acid compositions of A. keyserlingi silks to differ when collected in May compared to November, while those of L. hasselti did not. To ascertain whether their secondary structures were decoupled from spidroin expression, we performed solid-state nuclear magnetic resonance spectroscopy (NMR) analysis on the silks of all spiders collected in May. We found the distribution of alanine toward β-sheet and 3,10helix/random coil conformations differed between species, as did their relative crystallinities, with A. keyserlingi having the greatest 3,10helix/random coil composition and N. plumipes the greatest crystallinity. The protein secondary structures correlated with the mechanical properties for each of the silks better than the amino acid compositions. Our findings suggested that a differential distribution of alanine during spinning could decouple secondary structures from spidroin expression ensuring that silks of desirable mechanical properties are consistently produced. Alternative explanations include the possibility that other spidroins were incorporated into some silks. SN - 1422-0067 UR - https://www.unboundmedicine.com/medline/citation/27517909/Evidence_of_Decoupling_Protein_Structure_from_Spidroin_Expression_in_Spider_Dragline_Silks_ L2 - http://www.mdpi.com/resolver?pii=ijms17081294 DB - PRIME DP - Unbound Medicine ER -