Abstract:

The formation mechanism of the crystalline domain in Bombyx mori silk fibrion is just similar to that of α-synuclein (α-Syn), which is the pathogenic protein of human Parkinson's disease. That is to say, under the certain condition, a conservative sequence made of very hydrophobic amino acids and some random coils would cause the whole structure conversion and fibrillization of a protein. It had been found that the hydrophobic region of these two proteins was the key to the formation of β sheet. In order to study whether α-synuclein can be fibrillized after its aggregating core is replaced by another, we replaced the core region of α-Syn_1-74 (α-Syn₇₄) with the core region of B. mori silk fibrion using the PCR technique, and constituted a recombinant protein named as α-Syn₇₄SFX. After purification and incubation for 6 days, the structure of α-Syn₇₄SFX was examined with atomic force microscope (AFM) and ThT fluorescence. The results showed that fibrillization did not occur in α-Syn₇₄SFX. This suggests that the availability of a core region important to form β sheet and a random coil region does not necessarily make a protein to fibrillize. The research provided clues for the study of artificial silk.

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Key words: Bombyx mori, fibrion, α-synuclein, aggregation, fibrillization