Glyoxal modification mediates conformational alterations in silk fibroin: Induction of fibrillation with amyloidal features
Silkwormsilk 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 beta-sheet structure and self-assembly of silk fibroinwhich are regulated by many parameters. Glyoxal, a highly reactive alpha-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 micro-M) 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 glycationinducedmodification 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.
Volume 45, 2020
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