The conserved C-termini contribute to the properties of spider silk fibroins

Spider silk fibroins can adopt different structural states at high protein concentrations. They are soluble within the spinning dope of the glands, but readily converted into insoluble polymers upon extrusion. A contribution of the C-termini to the maintenance and conversion of these states is suggested by their predicted secondary structures and biochemical behavior in vitro. Special sequence parts endow the C-termini with the capability to promote both the solubility and aggregation of the fibroins depending on the environmental conditions.