Structure Characterization of Silk Fibroin Crystalline Domain Polypeptides Expressed in Escherichia coli

摘要

The molecular conformations of four silk fibroin crystalline analogues [GAGAG-X] 16(G,Gly;A,Ala;X=Ala,Ser,Tyr or Val,designated eGA,eGS,eGY or eGV),carried out using molecular design and expressed by Escherichia coil(E.coli),were evaluated by Raman spectra analysis.The abilities of forming β-sheet structure were determined by thioflavin T(ThT) fluorescence spectra analysis.In terms of molecular conformation,except eGY that could not form significant typical molecular conformation,eGS and eGV were mainly composed of β-sheets while eGA tended to form β-turn.β-turn was also present in eGY and absent in eGS and eGV.In terms of β-sheet structure,eGS had the highest β-sheet content,followed by eGV,and eGA had the lowest content,furthermore,β-sheet structures were more stable in eGS and eGV than those in eGA and eGY.