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Protoenzymes: The Case of Hyperbranched Polymer-Scaffolded ZnS Nanocrystals

preprint
revised on 11.03.2020 and posted on 11.03.2020 by Irena Mamajanov, Melina Caudan, Tony Z. Jia

Enzymes could be described as small-molecule, metal, or cluster catalysts augmented by biopolymeric scaffolds. It is conceivable that early in chemical evolution, ancestral enzymes opted for simpler, easier to assemble scaffolds. Herein, we describe such possible protoenzymes: hyperbranched polymer-scaffolded metal-sulfide nanocrystals. Hyperbranched polyethyleneimine (HyPEI) and glycerol citrate polymer-supported ZnS nanocrystals (NCs) are formed in a simple, abiotically plausible process. Transmission electron microscopy (TEM) analyses of HyPEI-supported NCs reveals spherical particles with an average size of 10nm that undergo only a modest aggregation over a 14-day incubation. The polymer-supported ZnS NCs are shown to possess a high photocatalytic activity in an eosin B photodegradation assay, making them an attractive model for the study of the origin of life under the “Zn world” theory dominated by a photocatalytic proto-metabolic redox reaction network. The catalyst, however, could be easily adapted to apply broadly to different protoenzymatic systems.

History

Email Address of Submitting Author

irena.mamajanov@elsi.jp

Institution

Tokyo Institute of Technology

Country

Japan

ORCID For Submitting Author

0000-0003-4682-8658

Declaration of Conflict of Interest

None

Exports