Editing Spider silk (section)

===Feedstock===
The molecular structure of unspun silk is both complex and long. Though this endows the fibres with desirable properties, it also complicates replication. Various organisms have been used as a basis for attempts to replicate necessary protein components. These proteins must then be extracted, purified, and then spun before their properties can be tested.

{| class="wikitable" style="text-align: center;"
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! scope="col" | Organism

! scope="col" | Details

! scope="col" | Average Maximum breaking stress (MPa)

! scope="col" | Average [[Deformation (mechanics)|Strain]] (%)

! scope="col" | Reference
|- scope=
| Darwin's bark spider (''Caerostris darwini'')
| Malagasy spider famed for making 25&nbsp;m long strands. "''C. darwini'' silk is more than twice as tough as any previously described silk"|| 1850 ±350 || 33 ±0.08 || <ref name="Agnarsson 10"/>
|- style=
| ''Nephila clavipes''
| Typical golden orb weaving spider || 710–1200 || 18–27 || <ref>{{cite journal |author= Elices, M.|author2= Plaza, G.R.|author3= Arnedo, M.A.|author4= Perez-Rigueiro, J.|author5= Torres, F.G.|author6= Guinea, G.|name-list-style= amp |date= 2009 |title= Mechanical Behavior of Silk During the Evolution of Orb-Web Spinning Spiders |journal= Biomacromolecules |volume= 10 |pages= 1904–10 |doi= 10.1021/bm900312c |pmid=19505138 |issue= 7}}</ref><ref>{{cite journal |author= Swanson, B. O.|author2= Blackledge, T. A.|author3= Summers, A. P.|author4= Hayashi, C. Y.|name-list-style= amp |date= 2006 |title= Spider dragline silk: Correlated and mosaic evolution in high-performance biological materials |journal= Evolution |volume= 60 |pages= 2539–51 |doi=10.1554/06-267.1 |pmid=17263115 |issue= 12|s2cid= 14862626|url= https://faculty.washington.edu/fishguy/Resources/Research_PDFs/2006-evolution-spider-silk-material-properties.pdf}}</ref>
|-

! scope="row" | ''[[Bombyx mori]]'' Silkworms
| Silkworms genetically altered to express spider proteins and fibres.<ref>{{cite journal |author= Shao, Z. Z.|author2= Vollrath, F.|name-list-style= amp |date= 2002 |title= Materials: Surprising strength of silkworm silk |journal= Nature |volume= 418 |pages= 741 |doi= 10.1038/418741a |issue=6899 |pmid=12181556|bibcode = 2002Natur.418..741S |s2cid= 4304912|doi-access= free }}</ref> || 660 || 18.5 || <ref>{{cite journal |author= Wen, H. X.|date= 2010 |title= Transgenic silkworms (Bombyx mori) produce recombinant spider dragline silk in cocoons |journal= Molecular Biology Reports |volume= 37 |pages= 1815–21 |doi= 10.1007/s11033-009-9615-2 |pmid=19633923 |issue= 4|s2cid= 12924107 |display-authors=etal}}</ref>
|-

! scope="row" | ''[[Escherichia coli]]''
| Synthesising a large and repetitive molecule (~300 [[Atomic mass unit|kDa]]) is complex, but required for the strongest silk. Here ''E. coli'' was engineered to produce a 556 kDa protein. Fibers spun from these synthetic spidroins are the first to fully replicate the mechanical performance of natural spider silk by all common metrics. || 1030 ±110 || 18 ±6 || <ref name="Bowen2018">{{cite journal |author= Bowen, C.H. |date= 2018 |title= Recombinant Spidroins Fully Replicate Primary Mechanical Properties of Natural Spider Silk |journal= Biomacromolecules |volume= 19 |issue= 9 |pages= 3853–60 |doi= 10.1021/acs.biomac.8b00980 |pmid=30080972|hdl= 2060/20180007385 |s2cid= 51930371 |hdl-access= free }}</ref>
|-

! scope="row" | Goats
| Genetically modified to secrete silk proteins in their milk. || 285–250 || 30–40 || <ref>{{cite journal |author=Elices, M.|author2=Guinea, G. V.|author3=Plaza, G. R.|author4=Karatzas, C.|author5=Riekel, C.|author6=Agulló-Rueda, F.|author7=Daza, R.|author8=Pérez-Rigueiro, J. |date= 2011 |title= Bioinspired Fibers Follow the Track of Natural Spider Silk |journal= Macromolecules |volume= 44 |pages= 1166–76 |doi= 10.1021/ma102291m|bibcode = 2011MaMol..44.1166E |issue=5 |s2cid=97699665 }}</ref>
|-

! scope="row" | Tobacco & potato plants
| Genetically modified to produce silk proteins. Patents were granted in 2010,<ref>{{cite patent| country = US| number =2008109923| status =patent| title = Expression of spider silk proteins| pubdate = 2010-05-25| invent1 = Lewis, R. V.| assign1 =University of Wyoming }}</ref> but no fibres have yet been described. || n/a || n/a || <ref>{{cite journal |author= Scheller, J.|author2= Conrad, U.|name-list-style= amp |date= 2005 |title= Plant-based material, protein and biodegradable plastic |journal= Current Opinion in Plant Biology |volume= 8 |pages= 188–96 |doi=10.1016/j.pbi.2005.01.010 |pmid=15753000 |issue= 2|bibcode= 2005COPB....8..188S}}</ref>
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