(A) ThT fluorescence of freshly purified 5 μM CsgA with or without 50 μM compound. Reduction in ThT fluorescence corresponds to inhibition of CsgA polymerization.
(B) CsgA solubility after overnight incubation with or without compound by SDS-PAGE. Compounds that inhibit CsgA polymerization kept CsgA in a soluble SDS-sensitive state.
(C) CsgA incubated overnight with compounds was spotted onto a nitrocellulose membrane and probed with a gammabody grafted with the CsgA R1 sequence that detects CsgA amyloid structure.
(D) Transmission electron microscopy of freshly purified CsgA incubated for 6 hr revealed abundant fibers, whereas no curli fibers were detected by when freshly purified CsgA was incubated for 6 hr with the inhibitor compound 7. Scale bars represent 0.5 μM.
See also Figure S1.