After produceing an octapeptide, GAGAGAGY, from Bombyx mori silkworm fibroin by hydrolysis strategy and synthesizing the peptide amphiphile of C12-GAGAGAGY, the role of Tyr played in the assembly of this PA was investigated. Due to the different acid dissociation constants of the carboxyl and phenolic hydroxyl groups on the Tyr, the PA showed unique pH sensitive assembly/ aggregation behaviors. It was found that not only the molecular-scale assemblies of the PA gradually changed from cylindrical nanofibers to nanoribbons with the decreasing of pH value, but also most of nanoribbons parallelly aggregated into bundles and finally formed hydrogel with hierarchical structures in the high concerntration. Furthermore, compearation on the behaviours of the isomeric peptide amphiphiles of C12-(GA)3(GY)1 in the aqueous solution presented that the location of Tyr rather than the other effects such as pH value etc. acted as an essential role in the assembling of such isomeric peptide amphiphiles, which took an example to show the undefined relation between chemical composition and aggregation/assembling of PAs .

Roles of Tyr played in a silk fibroin based peptide (GAGAGAGY) amphiphiles

254th National Meeting (2017)

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