Production of Bombyx mori Silk Fibroin Incorporated with Unnatural Amino Acids
- Publication date
- 2014
- Publisher
Abstract
Silk
fibroin incorporated with unnatural amino acids was produced
by in vivo feeding of <i>p</i>-chloro-, <i>p</i>-bromo-, and <i>p</i>-azido-substituted analogues of l-phenylalanine (Phe) to transgenic silkworms (Bombyx mori) that expressed a mutant of phenylalanyl-tRNA
synthetase with expanded substrate recognition capabilities in silk
glands. Cutting down the content of Phe in the diet was effective
for increasing the incorporation of Phe analogues but simultaneously
caused a decrease of fibroin production. The azide groups incorporated
in fibroin were active as chemical handles for click chemistry in
both the solubilized and the solid (fibrous) states. The azides survived
degumming in the boiling alkaline solution that is required for complete
removal of the sericin layer, demonstrating that AzPhe-incorporated
silk fibroin could be a versatile platform to produce “clickable”
silk materials in various forms. This study indicates the huge potential
of UAA mutagenesis as a novel methodology to alter the characteristics
of B. mori silk