Construction of an aptamer-conjugated molecular artificial enzyme with enhanced activity and selectivity

Although molecular artificial enzymes have displayed tremendous potential in many homogeneous reactions, their low catalytic selectivity is still a challenge. In this study, an aptamer strategy was developed to construct a molecular artificial enzyme (Apt-Tpy(Fe)) by covalently linking the catalytic site Tpy(Fe) to the CV aptamer, thereby providing a specific binding site for CV. The obtained Apt-Tpy(Fe) appeared to exhibit enhanced catalytic activity toward CV and pronounced catalytic suppression of other substrate analogues. This performance, therefore, results in a superior catalytic preference for CV. Moreover, based on computer simulations, the structure-function relationship of Apt-Tpy(Fe) was investigated, revealing that the affinity of the aptamer to CV as well as the orientation between the catalytic site and the substrate binding site decide the catalytic performance of Apt-Tpy(Fe) toward CV. This work provides a promising method for developing a molecular catalyst with enzyme-like activity and selectivity.