Engineering a zinc binding site into the de novo designed protein DS119 with a βαβ structure.

Functional proteins designed de novo have potential application in chemical engineering, agriculture and healthcare. Metal binding sites are commonly used to incorporate functions. Based on a de novo designed protein DS119 with a βαβ structure, we have computationally engineered zinc binding sites into it using a home-made searching program. Seven out of the eight designed sequences tested were shown to bind Zn(2+) with micromolar affinity, and one of them bound Zn(2+) with 1:1 stoichiometry. This is the first time that metalloproteins with an α, β mixed structure have been designed from scratch.