Fig. 3: In vivo selection of EPS in the formaldehyde assimilation module (M1).

a EPS candidates from E. coli that are known to be DHAP dependent aldolases. Phylogenetic relationship of the proteins is based on their sequence similarity (Supplementary Fig. 4 and “Methods”). FbaB is used as an out group. b A schematic representation of the ΔfrmTKT selection. Gene deletions are in red. Such a strain cannot synthesize the essential metabolite E4P, highlighted in yellow. Enzymes expressed from plasmid are in brown. Carbon sources are shown in purple. SoxA, sarcosine oxidase. Other abbreviations are the same as Fig. 2. c FucA and (d) RhaD, once overexpressed together with other EuMP enzymes, restored growth of the ΔfrmTKT strain in a sarcosine dependent manner. Strains omitted EPS (e) or EryC (f) overexpression failed to grow. Expressed plasmids (detailed in Supplementary Table 1) are shown at the top left corner of the curves. FbaA and YihT failed to support the growth, the results are shown in Supplementary Fig. 5. g Trace of ¹³C labeling from formaldehyde. h Labeling pattern of proteinogenic alanine (Ala), phenylalanine (Phe), and tyrosine (Tyr), within the strains ΔfrmTKT overexpressed FucA (pFEIIO) and RhaD (pREIIO), upon feeding with unlabeled glycerol and sarcosine-(methyl-¹³C). The accompanied results with unlabeled sarcosine are shown in Supplementary Fig. 6a. Source data are provided as a Source Data file.