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| - | '''''Spider Silk'''''
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| - | |Spider silk is comparable in strength to carbon fibres
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| - | |Highly structured at the nanometre scale – not good for synthetic materials
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| - | |Repetitive structures- GXG motif
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| - | |Glycine rich segments – hard and soft segments alternating
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| - | | '''Hard'''= hydrogen bonding cross-linked crystallites (polyalanine) forming an amorphic beta sheet structure,
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| - | |'''Soft'''= flexibility (Glycine rich)
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| - | |Major protein from Nephila clavipes – MaSP1 tandem variants of
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| - | |A GQG GYG GLG SQG A GRG GLG GQG A GA6GGx
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| - | |MaSP2 also has a repetitive structure – difference soft segment contains proline containing pentamers: The consensus repeat is _GPGGY GPGQQ.3GPSGPGS A8. Similar structure to Elastin – elastic properties of drag-line by the folding of pentamer structure.
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| - | |In the spider – silk in 3 phases
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| - | |1) Extremely viscous (withstand shear forces inside spider),
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| - | |2) Liquid crystallite lower viscosity (near exit duct/glycine rich may be involved),
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| - | |3) Insoluble fibre (result of dehydration and drawing).
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| - | |'''MaSP1 and MaSP2''' – Drag line
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| - | |'''MaSP1'''-Auxilary
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| - | |'''MaSP2'''- Glue silk only
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| - | |'''Neither'''- Cocoon silk
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| - | |Super contraction associated with pentamer motif when wet: low visco-elasticity
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| - | |Mimic natural proteins or simplify – Mimic structural significance still uncertain for some sequences
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| - | |DPB1- Optimised for ''B.subtilis''
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| - | |''B.subtilis'' potential host as simple secretion system compared to yeast. Secretion has advantages over expression in ''E.coli'' however; insufficient proportion of protein was secreted by yeast.
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| - | | '''Fahnestock et al 2000'''
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