Figure 1.

Assembly states of polymerized PfActI. (A) Representative gel of a standard pelleting assay of PfActI and α-actin at a total protein concentration of 4 µM, separated at 434,500 g (top) or 100,000 g (bottom) at 20 °C for 1 h. S and P stand for supernatant and pellet, respectively. Molecular weight standard sizes (in kDa) are indicated on the left. (B) Pelleting assay results of PfActI at 434,500 g (n = 12), at 100,000 g (n = 3), and α-actin at 434,500 g (n = 8), expressed as % of total protein in each fraction. Relative centrifugal forces have been indicated above each bar. (C) Two sequential pelleting assays (UC1 and UC2) of 10 µM PfActI, separated by 6 h of incubation at 22 °C, spun at 434,500 g for 1 h (n = 3). (D) DLS profiles of α-actin in the monomeric state, polymerized PfActI, and polymerized PfActI after ultracentrifugation at 100,000 g and 434,500 g. (E) Native PAGE of 25 µM polymerized PfActI before (left) and after (right) ultracentrifugation at 434,500 g in running conditions with sample-matched ATP:ADP ratio and 0.1 mM MgCl₂. The sample after ultracentrifugation represents the supernatant. Letters on the left indicate monomers (m), dimers (d), or polymers (p), based on relative mobility values obtained before⁷. Images in (E) have been lightly contrast-adjusted. Error bars in (B) and (C) represent standard deviation, ***p < 0.001, **p < 0.05, ns: not significant, Student’s t-test.