A peer-reviewed laboratory experiment obtained continuous fibers from short chains of designed proteins. Four repeating units were enough for the tested material; the strongest specimen reached 372.7 megapascals in tensile strength. The result addresses difficulties associated with much longer protein chains, while leaving industrial production and application safety to further evaluation.
Long chains of repeated proteins can be difficult to produce and purify. One peer-reviewed experiment instead strengthened the individual building blocks, then obtained continuous laboratory fibers from chains with four repeats. The designed proteins, named SuperMyo, draw on a region of titin, a protein with a mechanical role. Two versions, A339 and B42, were examined.[1]
The B42 group averaged 347.9 megapascals in tensile strength, compared with 302.0 for A339 and 245.6 for the comparison material. Its strongest specimen reached 372.7 megapascals. That maximum describes one specimen; the B42 average came from 18 fibers, while each other group contained 15.[1]
X-ray and Raman measurements examined alignment and the organization of folded protein structures in the fibers. Single-molecule measurements addressed the building blocks separately. Contacts between chains and processing also contribute to the behavior of a whole fiber. Other repeat counts yielded fibers too, so four units is not a universal minimum. Industrial output, durability in use and safety for human contact remain outside the demonstrated laboratory result.[1]
