Mamajanov Irena, Caudan Melina, Jia Tony Z
Earth Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8550, Japan.
Blue Marble Institute for Science, 1001 4th Ave, Suite 3201, Seattle, WA 98154, USA.
Life (Basel). 2020 Aug 13;10(8):150. doi: 10.3390/life10080150.
Enzymes are biological catalysts that are comprised of 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 process. Transmission electron microscopy (TEM) analyses of HyPEI-supported NCs reveal spherical particles with an average size of 10 nm 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.
酶是生物催化剂，由小分子、金属或簇催化剂与生物聚合物支架结合而成。可以想象，在化学进化的早期，原始酶选择了更简单、更易于组装的支架。在此，我们描述了这样一种可能的原始酶：超支化聚合物支架的金属硫化物纳米晶体。超支化聚乙烯亚胺（HyPEI）和甘油柠檬酸盐聚合物负载的硫化锌纳米晶体（NCs）通过一个简单的过程形成。对HyPEI负载的NCs进行的透射电子显微镜（TEM）分析显示，平均尺寸为10 nm的球形颗粒在14天的孵育过程中仅发生适度聚集。在曙红B光降解试验中，聚合物负载的硫化锌NCs显示出高光催化活性，使其成为在以光催化原始代谢氧化还原反应网络为主导的“锌世界”理论下研究生命起源的一个有吸引力的模型。然而，这种催化剂可以很容易地进行调整，以广泛应用于不同的原始酶系统。
