Foundation of the Outstanding Toughness in Biomimetic and Natural Spider Silk.

Spider dragline silk is distinguished through the highest toughness of all natural as well as artificial fiber materials. To unravel the toughness's molecular foundation and to enable manufacturing biomimetic analogues, we investigated the morphological and functional structure of recombinant fibers, which exhibit toughness similar to that of the natural template, on the molecular scale by means of vibrational spectroscopy and on the mesoscale by X-ray scattering. Whereas the former was used to identify protein secondary structures and their alignment in the natural as well as artificial silks, the latter revealed nanometer-sized crystallites on the higher structural level.

To spin or not to spin: spider silk fibers and more.

Spider silk fibers have a sophisticated hierarchical structure composed of proteins with highly repetitive sequences. Their extraordinary mechanical properties, defined by a unique combination of strength and extensibility, are superior to most man-made fibers. Therefore, spider silk has fascinated mankind for thousands of years.

Biomimetic fibers made of recombinant spidroins with the same toughness as natural spider silk.

Using a self-assembly of recombinant spidroins, biomimetic spinning dopes are produced and wet-spun into fibers. Upon varying the molecular design of the underlying recombinant spidroins, the influence of the amino- and carboxy-terminal domains, as well as the size of the repetitive core domain on fiber mechanics, is determined. Fiber toughness upon biomimetic processing equals and even slightly exceeds that of natural ones.

Recombinant production of spider silk proteins.

Natural spider silk fibers combine extraordinary properties such as stability and flexibility which results in a toughness superseding that of all other fiber materials. As the spider's aggressive territorial behavior renders their farming not feasible, the biotechnological production of spider silk proteins (spidroins) is essential in order to investigate and employ them for applications. In order to accomplish this task, two approaches have been tested: firstly, the expression of partial cDNAs, and secondly, the expression of synthetic genes in several host organisms, including bacteria, yeast, plants, insect cells, mammalian cells, and transgenic animals.

Improved semiquantitative Western blot technique with increased quantification range.

With the development of new interdisciplinary fields such as systems biology, the quantitative analysis of protein expression in biological samples gains more and more importance. Although the most common method for this is ELISA, Western blot also has advantages: The separation of proteins by size allows the evaluation of only specifically bound protein. This work examines the Western blot signal chain, determines some of the parameters relevant for quantitative analysis and proposes a mathematical model of the reaction kinetics.

Indirect detection of selective nuclear spin-spin interactions in a hostile environment.

We present a number of techniques which may be used to obtain precise values of selective spin-spin interactions between two nuclear spins in a hostile environment. Such an environment may be characterized by very fast relaxation and decoherence, e.g.