Fig 1.

Schematic of how to overcome the bundling issues of E. coli CsgA fibrils for cryo-EM data collection. The optimization process involved adjusting the medium type, induction temperature, and induction time to achieve the highest yield of CsgA monomer. Then, various conditions during fibrillation (pH, salt, agitation, and additives) and de-bundling methods (heat, detergent, sonication, and buffer exchange) after assembly were tested to obtain de-bundled CsgA fibrils suitable for cryo-EM imaging. Lastly, data processing procedures were fine-tuned to generate good 2D classes and 3D density maps.