ABSTRACT
Silkworm silk protein fibroin is widely exploited to develop novel silk-based biomaterials due to its stable b-sheetstructure, providing high crystallinity and tensile strength. The polymorphic behaviour of silk fibroin provides awindow to modulate its structural transitions during self-assembly for different functional outcomes. Most studiesare therefore mainly focused on formation of well-developed b-sheet structure and self-assembly of silk fibroinwhich are regulated by many parameters. Glyoxal, a highly reactive a-oxoaldehyde, reacts with different proteinsto form advanced glycation end products (AGEs) following Maillard-like reaction. Considering the significanceof protein modification by glyoxal-derived AGEs, in the present study the effect of glyoxal (250, 500 and1000 lM) on the structure of silk fibroin has been investigated. CD and fluorescence studies reveal that higherconcentrations of the a-oxoaldehyde induce considerable alterations of secondary and tertiary structure of theprotein leading to aggregation following incubation with for 3 weeks. The aggregates exhibit fibrillar morphologywith amyloidal nature as evident from SEM, FTIR and XRD experiments. The findings highlight that glycationinduced modification can be a possible approach for modulating the conformation of the silk protein which may berelevant in connection to clinical, biomedical or synthetic biology based applications.