A novel nickel-chelated surfactant for affinity-based aqueous two-phase micellar extraction of histidine-rich protein.
Aqueous two-phase micellar systems (ATPMSs) composed of nonionic surfactants are considered promising for the separation and purification of proteins. To improve the specificity of ATPMSs, a novel nickel-chelated surfactant was prepared by successive modifications of Triton X-114 (TX). Characterizations by Fourier transformation infrared spectroscopy demonstrated the successful synthesis of the nickel-chelated surfactant (TX-Ni). The cloud point, critical micelle concentration (CMC), molecular interaction parameter and micelle size were measured for the mixed surfactant system of TX-Ni and TX to achieve a full understanding of their aggregation behaviors. The results showed that mixed micelles were formed, and the cloud point increased with the mole fraction of TX-Ni because TX-Ni had a more hydrophilic head group than TX. Moreover, the reduction of micelle size revealed by light scattering experiments indicated that the insertion of TX-Ni inhibited the micellar growth due to the increased steric and electrostatic repulsion. Finally, the efficiency of TX-Ni as an affinity surfactant was demonstrated by the affinity partitioning of histidine-tagged enhanced green fluorescent protein with an over 20-fold increase of the partition coefficient (from 0.60 to 12.42). This affinity-based ATPMS is thus considered promising for providing a versatile platform for the separation of histidine-rich proteins.
Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
Shuo
S
Wang
Neng
N
Xiong
Xiao-Yan
XY
Dong
Yan
Y
Sun
D002614:Chelating Agents / Q000737:chemistry*; D008823:Micelles; D009532:Nickel / Q000737:chemistry*; D011506:Proteins / Q000302:isolation & purification*; D017550:Spectroscopy, Fourier Transform Infrared; D013501:Surface-Active Agents / Q000737:chemistry*; D000099053:Histidine-Rich Glycoprotein
D002614:Chelating Agents; D008823:Micelles; D011506:Proteins; D013501:Surface-Active Agents; D000099053:Histidine-Rich Glycoprotein; D009532:Nickel
Affinity partitioning; Aqueous two-phase micellar system; Cloud point; Green fluorescent protein; Nickel-chelated surfactant; Triton X-114