caa a22 4500 463232461 CHVBK 20180405153246.0 cr unu---uuuuu 170326e20071101xx s 000 0 eng 10.1007/s10853-007-1642-6 doi (NATIONALLICENCE)springer-10.1007/s10853-007-1642-6 Modifications of spider silk sequences in an attempt to control the mechanical properties of the synthetic fibers [Elektronische Daten] [Florence Teulé, William Furin, Alyssa Cooper, Joshua Duncan, Randolph Lewis] Bacteria were genetically engineered to produce two spider silk protein variants composed of basic repeat units combining a flagelliform elastic motif ([GPGGX]4) and a major ampullate silk strength motif ([linker/poly-alanine]. The secondary structures of the pure recombinant proteins in solution were determined by circular dichroism. The data presented suggest that the nature of the 5th and 10th amino acid (X) in the [GPGGX]2 elastic motif and temperature have an impact on the amount of β-sheet structures present in the proteins. More specifically, increasing temperatures seem to be positively correlated with β-sheet formation for both proteins and this state is irreversible or reversible when both X (5th and 10th) in the elastic motif are hydrophilic or hydrophobic respectively. Moreover, each pure silk-like protein was able to spontaneously self-assemble into films from aqueous solutions. Two kinds of synthetic fibers were made by pulling fibers from these preassembled films as well as spinning fibers from each protein resolubilized in HFIP. The mechanical data show that the pulled fibers are far tougher than the spun fibers suggesting a better fiber organization. Springer Science+Business Media, LLC, 2007 Teulé Florence Department of Molecular Biology (Dept. 3944), University of Wyoming, 1000 E. University Avenue, 82071, Laramie, WY, USA aut Furin William Department of Molecular Biology (Dept. 3944), University of Wyoming, 1000 E. University Avenue, 82071, Laramie, WY, USA aut Cooper Alyssa Department of Molecular Biology (Dept. 3944), University of Wyoming, 1000 E. University Avenue, 82071, Laramie, WY, USA aut Duncan Joshua Department of Molecular Biology (Dept. 3944), University of Wyoming, 1000 E. University Avenue, 82071, Laramie, WY, USA aut Lewis Randolph Department of Molecular Biology (Dept. 3944), University of Wyoming, 1000 E. University Avenue, 82071, Laramie, WY, USA aut Journal of Materials Science Springer US; http://www.springer-ny.com 42/21(2007-11-01), 8974-8985 0022-2461 42:21<8974 2007 42 10853 https://doi.org/10.1007/s10853-007-1642-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10853-007-1642-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Teulé Florence Department of Molecular Biology (Dept. 3944), University of Wyoming, 1000 E. University Avenue, 82071, Laramie, WY, USA aut NATIONALLICENCE 700 1- Furin William Department of Molecular Biology (Dept. 3944), University of Wyoming, 1000 E. University Avenue, 82071, Laramie, WY, USA aut NATIONALLICENCE 700 1- Cooper Alyssa Department of Molecular Biology (Dept. 3944), University of Wyoming, 1000 E. University Avenue, 82071, Laramie, WY, USA aut NATIONALLICENCE 700 1- Duncan Joshua Department of Molecular Biology (Dept. 3944), University of Wyoming, 1000 E. University Avenue, 82071, Laramie, WY, USA aut NATIONALLICENCE 700 1- Lewis Randolph Department of Molecular Biology (Dept. 3944), University of Wyoming, 1000 E. University Avenue, 82071, Laramie, WY, USA aut NATIONALLICENCE 773 0- Journal of Materials Science Springer US; http://www.springer-ny.com 42/21(2007-11-01), 8974-8985 0022-2461 42:21<8974 2007 42 10853 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer