Bioprocessing of silk proteins-controlling assembly

A model for silk processing in silkworms and spiders is proposed and based on the unique domain structure in the sequences of silk proteins. A hypothesis for the silk-spinning process begins with chain folding at lower concentrations of protein, proceeds through formation of micelles and then micellar aggregates (globules) through water loss and increasing protein concentration, and finally leads to fiber formation due to the phys- ical shear process during fiber spinning. Many aspects of this process can be mimicked in vitro, and the all-aqueous environment used is instructive as a model for polymer processing in general.