[Study on the pH-sensitive secondary structure of gamma-PGA embedded with magnetite nanoparticles].
The conformational transition of poly gamma-glutamic acid (gamma-PGA) embedded with magnetite nanoparticles under various pH conditions was investigated by Fourier transform infrared spectroscopy (FTIR). The secondary structure content was determined through the analysis of amide I bands of Fourier deconvolution spectra, secondary derivative spectra and the Gaussian curve fitting of the original infrared spectra. The results showed that the conformation of the gamma-PGA was affected by solution pH. The total contents of beta-sheet and beta-turn were higher than 65%, while alpha-helix and random coil were low. The content of beta-turn increased with increasing pH, while the beta-sheet decreased. Additionally, the zeta potential results showed that the pH-sensitive secondary structure of gamma-PGA had influence on the stability of suspension of magnetic gamma-PGA nanospheres. The minimum value of zeta potential (-35. 4 mV) was obtained at pH 10.2.
Zhang
Ju-Hua
JH
Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China. zhangjuhua05@yahoo.com.cn
Xing
Jian-Min
JM
Jiang
Yang-Yang
YY
Gao
Hong-Shuai
HS
Liu
Hui-Zhou
HZ
D000577:Amides / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D058185:Magnetite Nanoparticles; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared
D000577:Amides; D058185:Magnetite Nanoparticles; C511775:poly(gamma-glutamic acid); D011099:Polyglutamic Acid