Visible sensing of conformational transition in model silk peptides based on a gold nanoparticles indicator. Issue 70 (11th December 2019)

• Record Type: Journal Article
• Authors: Jia, Lan; Zhang, Jiabing; Liu, Sumei; Chen, Song; Zhu, Jingxin
• Is Part Of: RSC advances. Volume 9:Issue 70(2019)
• Page Start: 40924
• Page End: 40932
• Publication Date: 2019-12-11
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c9ra05842g
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Au NPs prepared in situ were utilized as a built-in colorimetric indicator to monitor conformation changes of a silk peptide. Abstract : To understand protein structural transition and β-sheet formation is of importance in disparate areas such as silk protein processing and disease related β-amyloid behavior. Herein, GAGSGAGAGSGAGY (GY-14), a tetradecapeptide based on the crystallizable sequence of silk fibroin, was employed as a model peptide of the crystalline regions of silk fibroin. Due to the incorporation of tyrosine (Y), GY-14 was able to reduce Au 3+ to Au NPs and further stabilize them without any external reducing or capping reagents to produce GY-14 stabilized Au NPs (GY-14@Au NPs). The in situ prepared GY-14@Au NPs were utilized as a built-in colorimetric indicator. The influences of specified physiological factors including decreasing the pH, the addition of calcium ions and isopropanol treatment on the self-assembly behavior of GY-14@Au NPs in aqueous solution have been studied. On the basis of transmission electron microscopy (TEM), dynamic light scattering (DLS), atomic force microscopy (AFM), Fourier transform infrared (FT-IR) spectroscopy and circular dichroism (CD) measurements, the color changes and the UV-Vis absorption peak shift of GY-14@Au NPs were attributed to the conformational change of the GY-14 peptide. The colorimetric readout can be seen with the naked eye, providing an efficient indicator to study the conformational changes of peptides exposed to various environmental stimuli.