Extended Data Fig. 9: A C-terminal motif reminiscent of DltX’s is found at the C-termini of MBOAT proteins that partner with DltD-like proteins in various prokaryotic cell envelope polymer acylation pathways.

a, Graphical depictions illustrate the genomic colocalization of genes encoding MBOAT proteins (green) and DltD-like proteins (blue) in bacterial cell envelope polymer acylation systems, as well as a system of unknown function found in some archaea. The chemical structures show a portion of the relevant polymer for each system, with the modification (acetylation in each of these cases), in blue^54,57,76. The lower right depicts a potential polymer acylation system of unknown function found in the archaeal species Nitrosopumilus adriaticus. We have designated the genes mbt1 for MBOAT1 and mbtp1 for MBOAT1 Partner. b, AlphaFold2 models of the two-protein complexes encoded by the genes from a. The models are all shown cytosolic side-down. c, Sequence logo generated by EVcouplings⁷⁰ with N. gonorrhoeae PatA as the query sequence showing the conservation of the final 51 amino acid positions of an alignment of bacterial cell envelope acylation-associated MBOAT proteins (as well as similar MBOAT proteins of unknown function), with the overall consensus sequence and corresponding NgPatA sequence shown underneath. The height of each individual letter represents the degree of conservation of that specific amino acid at the given position. The final transmembrane (TM) helix indicated is a prediction based on AlphaFold. d, Active sites of the MBOAT proteins of three of the systems shown in this figure (the corresponding active site for NgPatA is found in Fig. 4f) from AlphaFold2 models of the MBOAT proteins alone. These images are all shown with an ‘aerial’ view of the active site (looking toward the cytosol from the extracytoplasmic region). The catalytic histidine known to be required for all studied MBOAT proteins is shown in cyan, and the invariant tyrosine present in this class of MBOAT proteins is shown in purple.