GtcA is required for LTA glycosylation in Listeria monocytogenes serovar 1/2a and Bacillus subtilis

Jeanine Rismondo,Talal F.M Haddad,Yang Shen,Martin J Loessner,Angelika Gründling

doi:10.1016/j.tcsw.2020.100038

Jeanine Rismondo, Talal F.M Haddad + Show 3 more

Open Access

https://doi.org/10.1016/j.tcsw.2020.100038

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Abstract

The cell wall polymers wall teichoic acid (WTA) and lipoteichoic acid (LTA) are often modified with glycosyl and D-alanine residues. Recent studies have shown that a three-component glycosylation system is used for the modification of LTA in several Gram-positive bacteria including Bacillus subtilis and Listeria monocytogenes. In the L. monocytogenes 1/2a strain 10403S, the cytoplasmic glycosyltransferase GtlA is thought to use UDP-galactose to produce the C55-P-galactose lipid intermediate, which is transported across the membrane by an unknown flippase. Next, the galactose residue is transferred onto the LTA backbone on the outside of the cell by the glycosyltransferase GtlB. Here we show that GtcA is necessary for the glycosylation of LTA in L. monocytogenes 10403S and B. subtilis 168 and we hypothesize that these proteins act as C55-P-sugar flippases. With this we revealed that GtcA is involved in the glycosylation of both teichoic acid polymers in L. monocytogenes 10403S, namely WTA with N-acetylglucosamine and LTA with galactose residues. These findings indicate that the L. monocytogenes GtcA protein can act on different C55-P-sugar intermediates. Further characterization of GtcA in L. monocytogenes led to the identification of residues essential for its overall function as well as residues, which predominately impact WTA or LTA glycosylation.

Highlights

Bactoprenol, referred to as undecaprenyl phosphate (C55-P), is used for a wide range of processes in bacteria including the biosynthesis of peptidoglycan, lipopolysaccharides (LPS)and teichoic acids (Harkness and Braun, 1989, Kennedy, 1987, Weissborn et al, 1991, Soldo et al, 2002)
Homolog of L. monocytogenes, is necessary for the modification of wall teichoic acid (WTA) with GlcNAc residues (Fig. 1A) (Rismondo et al, 2018, Denes et al, 2015, Eugster et al, 2015). This suggests that B. subtilis and L. monocytogenes YfhO enzymes use the same C55-P-GlcNAc sugar molecule as substrate, they use lipoteichoic acid (LTA) and WTA, respectively, as acceptor molecules
Enzymes, the B. subtilis csbB-yfhO operon was expressed in L. monocytogenes strains lacking sugar modifications either on LTA or sugar modifications on WTA

Summary

Introduction

Teichoic acids (Harkness and Braun, 1989, Kennedy, 1987, Weissborn et al, 1991, Soldo et al, 2002) This molecule is an essential lipid-carrier to which sugars, monomeric subunits of cell wall components or complete polymers are linked in the cytoplasm of the cell. Teichoic acids are important cell wall polymers produced by Gram-positive bacteria They are either covalently linked to the peptidoglycan and referred to as wall teichoic acid (WTA) or embedded in the cytoplasm via a glycolipid anchor and called lipoteichoic acid (LTA) (Araki and Ito, 1989, Neuhaus and Baddiley, 2003, Percy and Gründling, 2014). The bactoprenol lipid carrier molecular C55-P is required at multiple steps during the synthesis and modification process of teichoic acids in Gram-positive bacteria

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