Fig. 3

Oligomeric forms of Walker motif mutants. a HS-AFM images of Walker A (1KA/AA and 2KT/AA) and Walker B (1E/Q and 2E/Q) mutants observed in the presence of 1 mM ATP. Scale bars, 20 nm. Z color bar, 0 to 9.6 nm. b Percentages of closed (black area) and open (hatched area) forms of 2KT/AA (1102 molecules), 1E/Q (388 molecules) and 2E/Q (516 molecules). c Histograms of contour length along the closed rings of ΔN-TClpB (397 molecules) and 2KT/AA (520 molecules). The center values and widths fitted by Gaussians are 35.2 nm and 5.3 nm (ΔN-TClpB), respectively, and 42.1 nm and 9.0 nm (2KT/AA), respectively. d Clipped HS-AFM images of 2KT/AA, 1E/Q, and 2E/Q mutants in the presence of 1 mM ATP. Scale bars, 5 nm. Z color bar, 0 to 9.1 nm. e Histograms of SDCH along the rings of 2KT/AA (3543 images from 32 molecules), 1E/Q (5279 images from 9 molecules) and 2E/Q (7287 images from 9 molecules). The frequencies of transition cycle between round and distorted closed states of 1E/Q and 2E/Q mutants are 0.28 ± 0.06 s⁻¹ and 0.022 ± 0.002 s⁻¹ (means ± s.d.), respectively