Atomic-level design of artificial superoxide dismutase with exceptional substrate specificity

Nanomaterial-based artificial enzymes can rival the activity of natural enzymes. However, their substrate specificity remains insufficient, which limits their practical applications in catalytic therapies. Herein, we combine atomic-precise synthesis with the philosophy of enzyme mimicry to successfully fabricate a single-atom manganese nanozyme (Mn-SAzyme) that structurally mimics the active center of natural Mn superoxide dismutases (SOD) with high precision. X-ray absorption spectroscopy experiments confirm a high structural similarity of the coordination shell of Mn centers in both Mn-SAzyme and natural SOD, including their elemental composition, coordination number, and bond length. As expected, Mn-SAzyme exhibits excellent SOD-like activity while showing negligible peroxidase, catalase, oxidase, or glutathione peroxidase-like activity, indicating its remarkable substrate specificity identical to that of natural SOD. Furthermore, it demonstrates promising therapeutic effects against acute kidney injury by eliminating reactive oxygen species and supplying SOD activity. Therefore, mimicking the active sites of natural enzymes at the atomic level creates unprecedented opportunities for developing nanozymes with superior substrate specificity and expanding the practical applications of enzymatic therapy.