Fig. 1. Self-assembling of CsgA proteins and establishment of single molecule system. (a) A schematic of self-assembling of CsgA proteins. (b) Schematic of the cross-linking of a single CsgA nanofiber. (c) The number of sticking microbeads observed per area in the cross-linking CsgA positive experiment and in the non-linking CsgA control experiment without adding EDAC and glutaraldehyde. (d and e) The relation between extension and rotation number and their schematic diagrams when multiple molecules or nanofibers attached on one microbead and glass. (f and g) The relation between extension and rotation number and their schematic diagram when a single molecule or nanofiber attached to one microbead and glass.