Fig. 9. B₁₂ production follows predicted metalation of Mg^IIGTP-CobW.

a Predicted metalation of Mg^IIGTP-CobW with Co^II and Zn^II (open and grey bars, respectively) in samples treated with defined media [Co^II]. Intracellular ΔG_Co(II) for each condition was calculated from rcnA expression (Fig. 8 and Supplementary Table 8). b B₁₂ produced by E. coli* strains with and without cobW (open and grey bars, respectively) following 4 h exposure to defined [Co^II]. B₁₂ was detected using a Salmonella AR2680 bioassay⁶⁵ (detects corrins, expected to be predominantly B₁₂; see “Methods”) and quantified by automated analysis of growth areas (Supplementary Fig. 29 and Supplementary Software 1). Inset shows original image and detected areas (each false coloured) for representative (n = 3) bioassay plate of B₁₂ calibration standards. All data are the mean ± SD of n = 3 biologically independent replicates (with errors in a propagated from qPCR data in Fig. 8b). Triangles represent individual experiments (some data points overlap, experimental values are available in Source Data files).