Fig. 2: FY mutants have a generalized secretion defect.

a FY mutants (but not the single meeF and meeY mutants) have reduced levels of secreted proteins in the spent medium (supernatant fraction) after overnight culture. Data are presented as mean ± standard deviation. ^***p = 0.0008, P values were calculated using Welch’s t test, two-tailed. n = 4 independent experiments. b FY mutants have dramatically reduced levels of Mn in the spent medium after overnight growth as monitored by ICP-MS analysis. Data are presented as mean ± standard deviation. ^**p = 0.001. P values were calculated using Welch’s t test, two-tailed. n = 3 independent experiments. c Silver-stained SDS-PAGE analysis showing reduced levels of extracellular proteins in the supernatant from the FY strain compared to WT and the single mutant strains after overnight growth (representing the same final culture density; Supplementary Fig. 1b). M, protein molecular weight marker. The image is representative of three experiments. d Western blot analysis of AprE-FLAG in supernatants. The image is representative of three independent experiments. Pellet samples and Ponceau-stained images (to demonstrate equal loading) are shown in Supplementary Fig. 4a. e Western blot analysis of heterologous AmyQ-His secretion. The image is representative of three independent experiments. Pellet samples and Ponceau-stained images are shown in Supplementary Fig. 4b. Source data are provided as a Source Data file.