Modification of actins by phallotoxins.

Phallotoxins bind to filamentous actin (F-actin) from liver or rabbit muscle with Kdiss approximately 10(-8) M. By this combination the structure of F-actin is stabilized to such an extent that it will be resistant to the depolymerizing action of 0.6 M KI and of deoxyribonuclease I, to denaturation by heat (70 degrees C), and to local ruptures caused by ultrasonication or by cytochalasin B. The structural features of phallotoxins essential for affinity to F-actin are specific.