Fig. 3: Stoichiometry and localisation of Pdu proteins.

a Gross number of the structural proteins per Pdu MCP. b Gross number of the catalytic proteins per Pdu MCP. Circle: signature peptide 1; triangle: signature peptide 2. The peptides with higher values were used for generating error bars (SD) and centre (mean), reasoning that signal loss from endogenous peptide is more likely. One peptide with higher values for PduE was excluded, because a time course digest revealed that slower digestion of this peptide could have led to overestimation. The stoichiometric data are shown in Table 1. The deletion of PduA resulted in significant changes in the abundance of shell proteins PduB, B’, and PduJ (p = 7.110e⁻⁷, 2.022e⁻⁸, and 0.013, respectively, n = 4, two-sided t test) and interiors PduC, D, E, O, and Q (p = 0.001, 0.0003, 0.002, 0.027, and 0.028, respectively, n = 4, two-sided t test). n number of biologically independent samples. ns, p > 0.05; *p < 0.05; **p < 0.01; ***p < 0.001. c The subcellular distribution of PduV, PduW, and PduX in S. Typhimurium LT2. PduV, PduW, PduT, and PduP were fused with eGFP at their C-termini and recombined into the S. Typhimurium LT2 chromosome. The eGFP fused to the C-terminal of PduX and the native eGFP were plasmid encoded. The spotty distribution of PduV, similar to that observed for PduT and PduP, indicated that PduV is localised with the Pdu MCPs. In contrast, PduW and PduX were localised throughout the cytoplasm, comparable to native eGFP, and did not possess typical Pdu MCP distribution in vivo. Source data of Fig. 3a, b are provided as Source Data files.