Fig. 2: A5 association and dissociation kinetics to and from a 2D-lattice.
From: Annexin-V stabilizes membrane defects by inducing lipid phase transition
a Schematic of the experimental setup. Membrane patches (DOPC/DOPS 50:50) are deposited on a mica sample support. The fluid cell contains HEPES buffer (pH 7.4) supplemented with 2 mM Ca2+. After addition of A5 to the fluid cell, HS-AFM observes the formation of A5 2D-lattices on membrane patches. b HS-AFM image frames (Supplementary Movie 1) showing that the borders of finite A5-lattices are dynamic. HS-AFM movie acquisition speed: 0.3 s per frame. c Time-lapse series (lines of different colors) of 2D-lattice boarder in polar coordinates. The reference point is the center of mass of the A5 lattice in the first panel of b. d Angle(θ)–time(t) map of A5 2D-lattice border radius (r). The false color scale represents varying radius from the lattice center to the edge. e Kymographs of A5 2D-lattice leading-edge radius at specific angle (white dashed lines in d). The red curves represent the idealized traces used for dwell-time analysis. f Dwell-time analysis of the association and dissociation kinetics at the leading edges of the A5 2D-lattice. g Histogram of the leading-edge radius change. The x-axis is scaled to half of the lattice unit cell length, 8.85 nm, corresponding to the lattice extension/decrease through association/dissociation of one A5 trimer. Each p6 unit cell contains two lattice A5 trimers. The relative energy diagram of A5 2D-lattice association and dissociation (red line) is estimated by N/N0 = exp(∆G/kBT), where N0 is the occurred events for ∆r = 0. The zero-energy level is defined at the positions without occurrence.
