High-speed AFM reveals accelerated binding of agitoxin-2 to a K ⁺ channel by induced fit

Agitoxin-2 (AgTx2) from scorpion venom is a potent blocker of K+ channels. The docking model has been elucidated, but it remains unclear whether binding dynamics are described by a two-state model (AgTx2-bound and AgTx2-unbound) or a more complicated mechanism, such as induced fit or conformational selection. Here, we observed the binding dynamics of AgTx2 to the KcsA channel using high-speed atomic force microscopy. From images of repeated...