Sulfonium-Containing Glycopolypeptides Tethering Trehalose for Protein Stabilization
Zongze Li, Kongying Zhu, Lixia Ren, Xiaoyan Yuan
Abstract
Protection of proteins is of great significance since external stimuli can cause denaturation due to aggregation. Herein, a series of well-defined cationic trehalose-glycopolypeptides, poly(ethylene glycol)-b-(l-methionine-g-trehalose)s (PEG45-b-(Met-g-Tre)x), were synthesized for stabilization of a model protein, glucose oxidase (GOx), against lyophilization and heating. The isothermal titration calorimetry results revealed that polyionic complexes (PICs) were formed between the synthesized trehalose-glycopolypeptides and GOx via electrostatic interactions. These PICs allowed GOx to maintain an approximately 80% enzymatic activity compared with native GOx after 6× lyophilization. Meanwhile, PEG45-b-(Met-g-Tre)x also provided a positive effect on the protection of GOx upon heating at 60 °C. Results of transmission electron microscopy suggested that the trehalose-glycopolypeptides could prevent protein aggregation, thereby maintaining the bioactive function of GOx. In brief, it provided a synthesis strategy for the precise preparation of trehalose-glycopolypeptides, as well as a suitable method for stabilization of proteins.