New proteins that link the regulation of sugar metabolism and peptidoglycan biosynthesis in the Gram-positive pathogen Listeria monocytogenes

• Applicant: Dr. Jeanine Rismondo
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 452709177

The gram-positive cell wall is an important bacterial structure that is essential for maintaining the bacterial shape and to withstand turgor pressure. It also serves as an important barrier for toxic compounds. It consists of a thick layer of peptidoglycan and cell wall polymers, which are either attached to the cell membrane, referred to as lipoteichoic acids, or covalently linked to the peptidoglycan, referred to as wall teichoic acids (WTA). Components of peptidoglycan can also be modified, for instance by O-acetylation or deacetylation, which increases the lysozyme resistance of bacteria. Due to its importance, the bacterial cell wall is one of the main targets for antibiotics. It is thus of utmost importance to know and understand all factors involved in its synthesis and modification. We have recently shown that the absence of the transmembrane component EslB of the ABC transporter EslABC of Listeria monocytogenes results in the production of a thinner, less O-acetylated peptidoglycan layer, which in turn leads to an increased lysozyme sensitivity. Based on the phenotypes, I hypothesize that the production or distribution of the peptidoglycan precursor UDP-N-acetylglucosamine (UDP-GlcNAc) is disturbed in the eslB mutant. Furthermore, we observed that the cell surface of the eslB mutant is more negatively charged, which led to the hypothesis that either the presentation or levels of WTA are altered in the absence of EslB. In the proposed research, we aim to test these hypotheses in order to gain more insights into the function of EslABC and potentially in the regulation and coordination of peptidoglycan and WTA biosynthesis.

• DFG Programme: Research Grants