Extended Data Figure 8 |. CD-NTases are encoded in conserved, poorly understood operons on mobile genetic elements.

a-, Operon structure for CD-NTases selected for in-depth characterization showing the conserved protein domains in CD-NTase adjacent genes (see Fig. 4a–c). Conserved operons were first identified by Burroughs et al. and operons are vertically organized by similarity to one another²². Where found, linked genes demonstrating CD-NTases are encoded on mobile genetic elements are indicated.

b, CD-NTases and their adjacently encoded “effector” proteins were coexpressed in E. coli and bacterial colony formation was quantified by spot dilution analysis. CD-NTases were inducibly expressed from a chloramphenicol resistant (Cm^R) vector and effectors were inducibly expressed from a carbenicillin resistant (Carb^R) vector. Bacteria harboring cognate CD-NTase / effector plasmids or control plasmids were plated on medium containing both inducers and incubated for 24 h at 37 °C. Data were not determined (N.D.) for CD-NTase036 because the effector was toxic to E. coli under non-inducing conditions. Data are the mean ± SEM of 3 independent experiments.

c, Spot dilution analysis of bacteria harboring the cognate CD-NTase-effector pair indicated, as quantified in b. The CD-NTase036-effector pair was not analyzed in this assay. Colony morphology indicates a potential interaction for some combinations, however, it is unclear how specific or significant this may be. Data are representative of 3 independent experiments.