Fig. 1.

Overview of hα₂M action based on biochemical analysis. In native (hα₂M)₄, the four intact bait regions (black) are exposed in the enclosed cavity (prey chamber), while the thioester bonds (pink) and RBDs (gray ovals) are hidden. Monomer pairs 1 and 2, as well as 3 and 4, are disulfide-linked protomers (dashed green lines); pairs 1 and 3, as well as 2 and 4, are vicinal protomers; and pairs 1 and 4, as well as 2 and 3, are diagonally opposite protomers. Each protomer thus has a vicinal, a disulfide-linked, and an opposite protomer. The mechanism of action is illustrated in four steps that result in three states as described in the text.