Chitosan/cellulose-based beads for the affinity purification of histidine-tagged proteins

Abstract

Chitosan/cellulose-based beads (CCBs) for the affinity purification of histidine-tagged proteins were prepared from chitosan/cellulose dissolved in ionic liquid as a solvent, and their structures were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, and thermogravimetric analysis. The affinity purification was used to separate hexahistidine-tagged (his-tagged) enhanced green fluorescent protein (EGFP) from Escherichia coli. The results showed that Zn-CCB exhibited more specific adsorption capacity toward the target protein compared with Ni-CCB and Cu-CCB. The maximum adsorption of EGFP was 1.84 mg/g of Zn-CCB, with 90% purity under the optimized conditions (ionic strength (1.0 M NaCl), pH (7.2) and imidazole concentration (500 mM)). In addition, a regeneration method for the sorbent was further developed by washing with ethylenediaminetetraacetic acid disodium and then reimmobilizing with metal ions. This technique is an alternative method for the purification of his-tagged proteins, making the process more economical, fast, stable, and large batch.

Supramolecular assemblies of histidine-containing peptides with switchable hydrolase and peroxidase activities through Cu(ii) binding and co-assembling

“…40,41 Simultaneously, absorption peaks at 3271–3287 cm −1 and 1589–1601 cm −1 attributed to the N–H stretching vibration and N–H bending vibration of amide groups decreased dramatically upon the addition of Cu 2+ ions. 42–44 However, the absorption band at 939–945 cm −1 which was ascribed to the out-of-plane bending vibration absorption of the carboxylic acid -OH group disappeared after the addition of Cu 2+ ions. 45 In addition, intense absorption bands at 1635–1643 cm −1 , corresponding to the adoption of β-sheet structures, shifted to higher frequencies (1647–1653 cm −1 ) in the spectra of the complex solution, implying the formation of random coil structures.…”