Extended Data Fig. 3: Characterization of the dynamic compartments within E. coli cells by urea perturbation.

a, Images of the I16-GFP expressing cells upon treatment with varying levels of urea. The recombinant E. coli cells were induced with 200 µM IPTG at 30 °C for 6 h, harvested, and resuspended in PBS buffer without and with the addition of urea. Following incubation at 25 °C for 20 min, the cells were imaged. Scale bars, 2.5 µm. b, Relative fluorescence of the cells upon treatment with varying levels of urea. Data are presented as mean ± s.d. of n = 3 biologically independent samples, with individual data points shown as black dots. The asterisks represent statistical significance with P‐value < 0.05 based on one-way analysis of variance (ANOVA). Data in a, b are representative of n = 3 independent experiments. Note that the data reveals disassembly of the I16-GFP condensates for the urea-treated cells in a dose-dependent manner, with the cell morphology and fluorescence well retained. These results indicate that the molecular interactions of forming spidroin condensates are relatively weak and easy to be broken with the hydrogen bonding disruptor (urea), thus offering a new line of evidence proving the condensates are liquid-like.