Supporting Figures

Files in this Data Supplement:

Fig. 7. Formation and spreading of a mound marked with green arrowhead in A. Upward and downward arrowheads mark the direction of slow scanning. Black lines mark the step position in the current image, and the white line marks the location of the step in the preceding image.

Fig. 8. Formation of a mound marked with green arrowhead in A. Molecular rows generated by this mound are covered by a multiple kink formation spreading upwards from the area below the field of view. Black arrows indicate scan directions. The black line marks the step position in the current image, and the white line marks the location of the step in the preceding image.

Fig. 9. Two mounds marked with green arrowheads appear in B. The upper mound is two or three molecules deep, and the lower mound is three or four molecules deep. The lower mound is seen ≈2 min after its formation and has grown sideways. Note the slower growth or lack of growth in the direction perpendicular to the step.(C) Straight step is restored after molecular rows from the two mound merge. (D) A multiple kink coming from the area below the field of view covers the observed step segment. Times on each image mark the period after the beginning of scanning in Fig. 8A. Black arrows indicate scan directions. Black lines mark the step position in the current image, and white lines mark the location of the step in the preceding image.

Fig. 10. A three- or four-molecule-deep mound marked with the green arrowhead appears in B. The mound is seen ≈3 min after its formation and has grown sideways. Note slower growth or lack of growth in direction perpendicular to step. Black arrows indicate scan directions. (A) The black line marks step position. (B) The white line marks the location of the step in the preceding image.

Fig. 11. Increase in the zoom level leading to molecular resolution images shown in Fig. 4. This sequence demonstrates that observations of multiple kinks and mounds are carried out at trains of parallel straight steps. A pair of upward and downward scans are shown for each zoom level. One or two pairs at each zoom level showing essentially similar images are omitted. Black arrows indicate scan directions.

Fig. 12. Association of clusters marked with arrowheads to a multiple kink at the upper step and to a straight step segment at the lower step. Black arrows indicate scan directions. White lines mark the location of the step in the preceding image.

Fig. 13. Schematic illustration of distribution of insulin molecules and 2D clusters on terraces between steps. Because of the incorporation of molecules into steps, denuded zones along the steps exist in which the surface concentration of insulin is lower. Evidence in refs. 1 and 2 suggest that the width of the denuded zone is ≈50 nm. Because of a likely exchange between molecules and 2D islands, the concentration of 2D islands in the denuded zones is also lower. The association of an island to a step and the creation of a multiple kink promotes the step closer to the denuded zone, where the island concentration is higher, and this increases the probability of association of another island and the creation of even larger kink agglomeration.

1. Reviakine, I., Georgiou, D. K. & Vekilov, P. G. (2003) J. Am. Chem. Soc. 125, 11684–11693.

2. Georgiou, D. K. (2003) Master’s thesis (University of Houston, Houston).