1.D.139. The Computationally Designed Transmembrane Protein Pore (CD-TMPP) Family
The de novo design of stable, well-defined transmembrane protein pores that are capable of conducting ions selectively or are large enough to enable the passage of small-molecule fluorophores has been achieved (Xu et al. 2020). Thus, computational designed protein pores formed by two concentric rings of alpha-helices that are stable and monodisperse in both their water-soluble and their transmembrane forms has been reported by Xu et al. 2020. Crystal structures of the water-soluble forms of a 12-helical pore and a 16-helical pore closely match the computational design models. Patch-clamp electrophysiology experiments showed that the transmembrane form of the 12-helix pore enables the passage of ions across the membrane with high selectivity for potassium over sodium; ion passage is blocked by specific chemical modifications at the pore entrance. When incorporated into liposomes using in vitro protein synthesis, the transmembrane form of the 16-helix pore-but not the 12-helix pore enabled the passage of biotinylated Alexa Fluor 488. A cryo-EM structure of the 16-helix transmembrane pore closely matched the design model. The ability to produce structurally and functionally well-defined transmembrane pores opens the door to the creation of designer channels and pores for a wide variety of applications.