Synergistic Effect of Graphene Oxide and Different Valence of Cations on Promoting Catalase Crystallization

Abstract

This study tests the effect of using the combination of graphene oxide (GO) with different valence cations as a heterogeneous nucleant on promoting catalase crystallization. By using GO and three types of salts with different valences, NaCl, MgCl2, and YCl3, the addition of GO with all three salts resulted in an increase in the percentage of crystal drops and a decrease in induction time. The experimental results further verified that there is a synergistic effect of GO and cations as the percentage of crystal drops was higher when GO with cations was added compared to control experiments where only GO or cations presented. It was also observed that the improvement in crystallization became more significant when cations with higher valence were utilized. It is believed that the enhancement in crystallization was due to the synergistic effect arising from the cation-π and electrostatic interactions between GO sheets and cations. These interactions subsequently contributed to the positively charged salt, which adsorbed and connected both negatively charged catalase molecules and the GO surfaces, increasing the local protein concentration and leading to crystallization. In addition, we compared LaCl3 and CeCl3 with YCl3 to verify the effect of the same valence salt on catalase crystallization and found that the higher the charge density, the more pronounced the promotion effect. This study provides a new protein crystallization methodology by exploiting GO with cations as heterogeneous nucleant to promote catalase crystallization and brings about a new model for investigating protein crystallization mechanisms.

Cation–π Interactions in Graphene‐Containing Systems for Water Treatment and Beyond

“…The crystallization of catalase was found to be promoted using the combination of GO and cations (Na + , Mg 2+ , and Y 3+ ) as a heterogeneous nucleant. [ 88 ] An increase in the percentage of crystal drops and a decrease in induction time were observed when GO and cations were added. The results also proved that GO and cations worked in concert, indicating that the promoting effects were more significant when they coexisted.…”

Graphene Quantum Dots as Nucleants for Protein Crystallization

“…Alternatively, the addition of nanomaterials into protein solutions has been demonstrated to promote the crystallization processes, in particular, by accelerating the nucleation of protein molecules, which is a prerequisite step for the crystallization. − For example, various nanomaterials such as gold nanoparticles, graphene layers, and graphene quantum dots (GQDs) have been incorporated in the protein crystallization. − Among them, carbon-based graphene nanomaterials are particularly ideal for promoting protein crystallization due to their excellent chemical stability and large surface area for protein adsorption. Graphene is an allotrope of carbon in which the carbon atoms form an essentially two-dimensional (2D) nanostructure and is readily available with well-defined properties, including excellent electronic, thermal, chemical, − and physical properties .…”

Cation–π aggregation-induced white emission of moisture-resistant carbon quantum dots: a comprehensive spectroscopic study

“…What is more important is that the opposite charge between surface functional groups of the CQDs and Na + stiffens linking/bridging between the CQDs-CQDs structures through non-covalent cation–π interactions. 83 In addition, this issue demonstrates that Na + ions successfully adsorbed on the surface of the CQDs by cation–π interactions. This observation is in line with the interpretations of Raman results discussed in Section 3.1.…”