The first three proteins form a core complex that consists of one Toc159, four to five Toc34s, and four Toc75s that form four holes in a disk 13 nanometers across.
As primeiras tres proteínas forman un complexo central que consta dun Toc159, de catro a cinco Toc34s, e catro Toc75s que forman catro buratos nun disco de 13 nanómetros de diámetro.