FIGURE 2.

Schematic representation of most effective systems protecting L. monocytogenes from acidic stress. All systems are activated under mild acidic stress, with GadD2T2 system mostly effective under extreme acidic stress (adapted from Lund et al., 2020). F₀F₁-ATPase is shown in blue-green. ArgD/AguD transporter is shown in purple. A, ArcA (arginine), AguA1 (agmatine) deiminase; B, ArcB/AguB carbamoyl-transferase; C, ArcC/AguC carbamate kinase. GadT1 and GadT2 refer to glutamate (Glu)/GABA antiporters. GadD1, GadD2, and GadD3 are glutamate decarboxylase isoforms. Orn, ornithine. Put, putrescine. DnaK, chaperone. All membrane proteins are localized in lipid bilayer of plasma membrane, which also undergoes a decrease in membrane fluidity (downward pointing arrow, on leftmost side). Multilayered peptidoglycan of cell wall is schematically represented above plasma membrane. Created with BioRender.com.