Figure 1. Macrocolony morphology and lower expression of CsgD and the curli operon indicates increased activity of PdeC variants unable to form disulfide bonds in the periplasmic loop of the CSS domain.

1. Macrocolonies of Escherichia coli K‐12 strain AR3110 expressing the indicated PdeC versions under control of the tac promoter from the low copy number plasmid pCAB18 were grown on salt‐free LB (LBnoS) or YESCA agar plates supplemented with the matrix dye Congo red (CR) for 5 days at 28°C. For comparison with morphological patterns of macrocolonies of standard strains, see Appendix Fig S1.
2. Derivatives of strain W3110 carrying a single copy csgB::lacZ reporter fusion and containing the indicated plasmids were grown in LB medium. Samples were taken during the growth of the cultures (numbers refer to hours of growth and respond to data sampling and measurement points shown in C; on, overnight). Cellular CsgD levels were determined by immunoblotting.
3. From the same samples as in (B), specific β‐galactosidase activities expressed from csgB::lacZ were determined.

Source data are available online for this figure.