Sub-micro- and nano-sized polyethylene terephthalate deconstruction with engineered protein nanopores
Ana Robles‐Martín, Rafael Amigot‐Sánchez, Laura Fernández-López, José L. González-Alfonso, Sergi Rodà, Víctor Alcolea-Rodriguez, Diego Heras‐Márquez, David Almendral, Cristina Coscolín, Francisco J. Plou, Raquel Portela, Miguel Á. Bañares, Álvaro Martínez‐del‐Pozo, Sara García‐Linares, Manuel Ferrer, Vı́ctor Guallar
Abstract
Abstract The identification or design of biocatalysts to mitigate the accumulation of plastics, including sub-micro- and nano-sized polyethylene terephthalate (nPET), is becoming a global challenge. Here we computationally incorporated two hydrolytic active sites with geometries similar to that of Idionella sakaiensis PET hydrolase, to fragaceatoxin C (FraC), a membrane pore-forming protein. FraC m1/m2 could be assembled into octameric nanopores (7.0 nm high × 1.6–6.0 nm entry), which deconstructed (40 °C, pH 7.0) nPET from GoodFellow, commodities and plastic bottles. FraC m1 and FraC m2 degrade nPET by endo- and exo-type chain scission. While FraC m1 produces bis(2-hydroxyethyl) terephthalate as the main product, FraC m2 yields a high diversity of oligomers and terephthalic acid. Mechanistic and biochemical differences with benchmark PET hydrolases, along with pore and nPET dynamics, suggest that these pore-forming protein catalytic nanoreactors do not deconstruct macro-PET but are promising in nanotechnology for filtering, capturing and breaking down nPET, for example, in wastewater treatment plants.