Fig. 1.

A schematic diagram of the Listeria monocytogenes surfactome and its structures affecting biofilm formation on abiotic surface. Surfactome is composed from carbohydrates (peptidoglycan, lipoteichoic acids – LTA and wall teichoic acids – WTA), cell wall proteins and part of the flagellar apparatus. These structures are located at the surface, but the metabolism of these components is taking place in the cytosol, at the membrane and on the surface, and when relevant we consider all enzymes affecting surface structures, directly or indirectly, by their activity. The structures in bold are involved in biofilm formation and were either validated for their role in biofilm formation or their role was indicated by two or more transposon mutagenesis library screens or both. The dashed line (‐ ‐ ‐ ‐) is used to indicate either multistep synthesis procedure that is not completely presented here or the synthesis steps are unknown.

The peptidoglycan synthesis (A) starts in the cytoplasm and continues at the cell surface after monomers are flipped across the membrane, the assembly of peptidoglycan is carried out by multimodular penicillin‐binding proteins (PBP). Peptidoglycan turnover (B) takes place directly at the cell wall by multiple autolysins. The glycolipid and the LTA backbone are synthesized by multiple enzyme system (C) and decorated by galactose (not shown) and d‐alanine (D) using DltABCD system. Currently, we have limited data on WTA backbone synthesis (E), but WTA glycosylation of serotype 1/2b by N‐acetylglucosamine (F) and rhamnose (G) is known and its absence negatively affects biofilm formation. The rhamnose on WTA is needed in serotype 1/2a for proper internalin B (InlB) positioning at the cell wall and its full function. Other internalins belong to the group of LPXTG proteins that are covalently bound to the peptidoglycan by sortase A via LPXTG motif (H). They are the most abundant proteins in the cell wall of Listeria. Flagellar apparatus (I) is the structure spanning the cell membrane and cell wall enabling Listeria motility at temperatures below 30 °C.