Protein-caged zinc porphyrin as a carbonic anhydrase mimic for carbon dioxide capture

Haixia Chi; Han Chen; Kai Gong; Xiaoqiang Wang; Youming Zhang

doi:10.1038/s41598-020-76482-8

Protein-caged zinc porphyrin as a carbonic anhydrase mimic for carbon dioxide capture

Sci Rep. 2020 Nov 11;10(1):19581. doi: 10.1038/s41598-020-76482-8.

Authors

Haixia Chi¹, Han Chen², Kai Gong¹, Xiaoqiang Wang³, Youming Zhang⁴

Affiliations

¹ Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China.
² State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, China.
³ State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, China. wangxq001@upc.edu.cn.
⁴ Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China. zhangyouming@sdu.edu.cn.

Abstract

Zinc tetraphenylporphyrin (Zn-TPP) solubilized by GroEL protein cage was prepared as a supramolecular mimic of carbonic anhydrase (CA) for CO₂ capture. It is shown that the soluble Zn-TPP-GroEL complex can be formed easily by detergent dialysis. The Zn-TPP/GroEL binding ratio was found to increase with their dialysis ratio until reaching the maximum of about 30 porphyrins per protein cage. Moreover, the complex showed hydrase activity that catalyzes the CO₂ hydration in HCO₃^- and H⁺. It is further seen that the catalytic activity of Zn-TPP-GroEL was about one-half of that of a bovine CA at 25 °C. On the other hand, as the temperature was increased to 60 °C close to an industrial CO₂ absorption temperature, the natural enzyme lost function while Zn-TPP-GroEL exhibited better catalytic performance indicative of a higher thermal stability. Finally, we demonstrate that the GroEL-solubilized Zn-TPP is able to accelerate the precipitation of CO₂ in the form of CaCO₃ and has better long-term performance than the bovine CA. Thus a new type of nano-caged system mimicking natural CAs for potential applications in carbon capture has been established.

Publication types

Research Support, Non-U.S. Gov't