Self-assembly of MinE1-31 on mica under different buffer conditions.
AFM images of MinE1-31 self-assembled into straight (A and D), bent (B and E) and highly curved fibrils (C and F) in imaging buffers A, B and C, respectively. Graphs (G–I) show the height profiles corresponding to the green lines in images (D), (E) and (F). The four line profiles (I1–4) associated with (F) show alternating variations in the height (hc = 3.5 ± 0.3 nm, n = 34; hc' = 4.7 ± 0.3 nm, n = 32; green double arrows) along the curved fibrillar structure. White arrows in (D) and (E) indicate where protofibrils are visible. (E) High resolution image of the outlined square region in (B). Purple arrow indicates newly growing fibril. It should be noted that the feature of double fibrils in (E) is not a result of the double-tip artifact, because triple fibrils are also observed, as indicated by yellow arrows. Red double arrows in (G, H, I1 and 3) indicate the separation distance between protofibrils (D) and fibrils (E and F). hc and hc' denote the height of fibrils in imaging buffer C. The peptide concentration used in imaging buffers A, B and C, was 24, 41, and 18 μM, respectively.