scholarly journals Genes Required for Bacillus anthracis Secondary Cell Wall Polysaccharide Synthesis

2016 ◽  
Vol 199 (1) ◽  
Author(s):  
So-Young Oh ◽  
J. Mark Lunderberg ◽  
Alice Chateau ◽  
Olaf Schneewind ◽  
Dominique Missiakas
Keyword(s):  
Cell Wall ◽  
Bacillus Anthracis ◽  
Vegetative Growth ◽  
Cell Shape ◽  
Secondary Cell Wall ◽  
Cell Wall Polysaccharide ◽  
Genetic Determinants ◽  
Content Type ◽  
Repeat Structure ◽  
Layer Assembly

ABSTRACT The secondary cell wall polysaccharide (SCWP) is thought to be essential for vegetative growth and surface (S)-layer assembly in Bacillus anthracis; however, the genetic determinants for the assembly of its trisaccharide repeat structure are not known. Here, we report that WpaA (BAS0847) and WpaB (BAS5274) share features with membrane proteins involved in the assembly of O-antigen lipopolysaccharide in Gram-negative bacteria and propose that WpaA and WpaB contribute to the assembly of the SCWP in B. anthracis. Vegetative forms of the B. anthracis wpaA mutant displayed increased lengths of cell chains, a cell separation defect that was attributed to mislocalization of the S-layer-associated murein hydrolases BslO, BslS, and BslT. The wpaB mutant was defective in vegetative replication during early logarithmic growth and formed smaller colonies. Deletion of both genes, wpaA and wpaB, did not yield viable bacilli, and when depleted of both wpaA and wpaB, B. anthracis could not maintain cell shape, support vegetative growth, or assemble SCWP. We propose that WpaA and WpaB fulfill overlapping glycosyltransferase functions of either polymerizing repeat units or transferring SCWP polymers to linkage units prior to LCP-mediated anchoring of the polysaccharide to peptidoglycan. IMPORTANCE The secondary cell wall polysaccharide (SCWP) is essential for Bacillus anthracis growth, cell shape, and division. SCWP is comprised of trisaccharide repeats (→4)-β-ManNAc-(1→4)-β-GlcNAc-(1→6)-α-GlcNAc-(1→) with α-Gal and β-Gal substitutions; however, the genetic determinants and enzymes for SCWP synthesis are not known. Here, we identify WpaA and WpaB and report that depletion of these factors affects vegetative growth, cell shape, and S-layer assembly. We hypothesize that WpaA and WpaB are involved in the assembly of SCWP prior to transfer of this polymer onto peptidoglycan.

scholarly journals Bacillus anthracistagOIs Required for Vegetative Growth and Secondary Cell Wall Polysaccharide Synthesis

2015 ◽  
Vol 197 (22) ◽  
pp. 3511-3520 ◽  
Author(s):  
J. Mark Lunderberg ◽  
Megan Liszewski Zilla ◽  
Dominique Missiakas ◽  
Olaf Schneewind
Keyword(s):  
Cell Wall ◽  
Bacillus Anthracis ◽  
Vegetative Growth ◽  
Cell Shape ◽  
Secondary Cell Wall ◽  
Cell Wall Polysaccharide ◽  
Content Type ◽  
Phosphodiester Bonds ◽  
Acid Labile ◽  
Layer Assembly

ABSTRACTBacillus anthraciselaborates a linear secondary cell wall polysaccharide (SCWP) that retains surface (S)-layer and associated proteins via their S-layer homology (SLH) domains. The SCWP is comprised of trisaccharide repeats [→4)-β-ManNAc-(1→4)-β-GlcNAc-(1→6)-α-GlcNAc-(1→] and tethered via acid-labile phosphodiester bonds to peptidoglycan. Earlier work identified UDP-GlcNAc 2-epimerases GneY (BAS5048) and GneZ (BAS5117), which act as catalysts of ManNAc synthesis, as well as a polysaccharide deacetylase (BAS5051), as factors contributing to SCWP synthesis. Here, we show thattagO(BAS5050), which encodes a UDP-N-acetylglucosamine:undecaprenyl-PN-acetylglucosaminyl 1-P transferase, the enzyme that initiates the synthesis of murein linkage units, is required forB. anthracisSCWP synthesis and S-layer assembly. Similar togneY-gneZmutants,B. anthracisstrains lackingtagOcannot maintain cell shape or support vegetative growth. In contrast, mutations in BAS5051 do not affectB. anthraciscell shape, vegetative growth, SCWP synthesis, or S-layer assembly. These data suggest that TagO-mediated murein linkage unit assembly supports SCWP synthesis and attachment to the peptidoglycan via acid-labile phosphodiester bonds. Further,B. anthracisvariants unable to synthesize SCWP trisaccharide repeats cannot sustain cell shape and vegetative growth.IMPORTANCEBacillus anthraciselaborates an SCWP to support vegetative growth and envelope assembly. Here, we show that some, but not all, SCWP synthesis is dependent ontagO-derived murein linkage units and subsequent attachment of SCWP to peptidoglycan. The data implicate secondary polymer modifications of peptidoglycan and subcellular distributions as a key feature of the cell cycle in Gram-positive bacteria and establish foundations for work on the molecular functions of the SCWP and on inhibitors with antibiotic attributes.

scholarly journals LytR-CpsA-Psr Enzymes as Determinants of Bacillus anthracis Secondary Cell Wall Polysaccharide Assembly

2014 ◽  
Vol 197 (2) ◽  
pp. 343-353 ◽  
Author(s):  
Megan Liszewski Zilla ◽  
Yvonne G. Y. Chan ◽  
Justin Mark Lunderberg ◽  
Olaf Schneewind ◽  
Dominique Missiakas
Keyword(s):  
Cell Wall ◽  
Bacillus Anthracis ◽  
Chain Length ◽  
Secondary Cell Wall ◽  
Teichoic Acid ◽  
Cell Wall Polysaccharide ◽  
Wall Teichoic Acid ◽  
Content Type ◽  
Associated Proteins ◽  
Layer Assembly

Bacillus anthracis, the causative agent of anthrax, replicates as chains of vegetative cells by regulating the separation of septal peptidoglycan. Surface (S)-layer proteins and associated proteins (BSLs) function as chain length determinants and bind to the secondary cell wall polysaccharide (SCWP). In this study, we identified theB. anthracislcpDmutant, which displays increased chain length and S-layer assembly defects due to diminished SCWP attachment to peptidoglycan. In contrast, theB. anthracislcpB3variant displayed reduced cell size and chain length, which could be attributed to increased deposition of BSLs. In other bacteria, LytR-CpsA-Psr (LCP) proteins attach wall teichoic acid (WTA) and polysaccharide capsule to peptidoglycan.B. anthracisdoes not synthesize these polymers, yet its genome encodes six LCP homologues, which, when expressed inS. aureus, promote WTA attachment. We propose a model wherebyB. anthracisLCPs promote attachment of SCWP precursors to discrete locations in the peptidoglycan, enabling BSL assembly and regulated separation of septal peptidoglycan.

scholarly journals Bacillus anthracis lcpGenes Support Vegetative Growth, Envelope Assembly, and Spore Formation

2015 ◽  
Vol 197 (23) ◽  
pp. 3731-3741 ◽  
Author(s):  
Megan Liszewski Zilla ◽  
J. Mark Lunderberg ◽  
Olaf Schneewind ◽  
Dominique Missiakas
Keyword(s):  
Cell Wall ◽  
Bacillus Anthracis ◽  
Cell Size ◽  
Chain Length ◽  
Vegetative Growth ◽  
Secondary Cell Wall ◽  
Spore Formation ◽  
Content Type ◽  
Size And Shape ◽  
Layer Assembly

ABSTRACTBacillus anthracis, a spore-forming pathogen, replicates as chains of vegetative cells by regulating the separation of septal peptidoglycan. Surface (S)-layer proteins andB. anthracisS-layer-associated proteins (BSLs) function as chain length determinants and are assembled in the envelope by binding to the secondary cell wall polysaccharide (SCWP).B. anthracisexpresses six different genes encoding LytR-CpsA-Psr (LCP) enzymes (lcpB1to -4,lcpC, andlcpD), which when expressed inStaphylococcus aureuspromote attachment of wall teichoic acid to peptidoglycan. Mutations inB. anthracislcpB3andlcpDcause aberrations in cell size and chain length that can be explained as discrete defects in SCWP assembly; however, the function of the otherlcpgenes is not known. By deleting combinations oflcpgenes from theB. anthracisgenome, we generated variants with singlelcpgenes.B. anthracisexpressinglcpB3alone displayed physiological cell size, vegetative growth, spore formation, and S-layer assembly. Strains expressinglcpB1orlcpB4displayed defects in cell size and shape, S-layer assembly, and spore formation yet sustained vegetative growth. In contrast, thelcpB2strain was unable to grow unless the gene was expressed from a multicopy plasmid (lcpB2++), and variants expressinglcpCorlcpDdisplayed severe defects in growth and cell shape. ThelcpB2++,lcpC, orlcpDstrains supported neither S-layer assembly nor spore formation. We propose a model whereby LCP enzymes fulfill partially overlapping functions in transferring SCWP molecules to discrete sites within the bacterial envelope.IMPORTANCEProducts of genes essential for bacterial envelope assembly represent targets for antibiotic development. The LytR-CpsA-Psr (LCP) enzymes tether bactoprenol-linked intermediates of secondary cell wall polymers to the C6 hydroxyl ofN-acetylmuramic acid in peptidoglycan; however, the role of LCPs as a target for antibiotic therapy is not defined. We show here that LCP enzymes are essential for the cell cycle, vegetative growth, and spore formation ofBacillus anthracis, the causative agent of anthrax disease. Furthermore, we assign functions for each of the six LCP enzymes, including cell size and shape, vegetative growth and sporulation, and S-layer and S-layer-associated protein assembly.

scholarly journals Distinct Pathways Carry Out α and β Galactosylation of Secondary Cell Wall Polysaccharide in Bacillus anthracis

2020 ◽  
Vol 202 (15) ◽  
Author(s):  
Alice Chateau ◽  
So Young Oh ◽  
Anastasia Tomatsidou ◽  
Inka Brockhausen ◽  
Olaf Schneewind ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Anthracis ◽  
Secondary Cell Wall ◽  
Turgor Pressure ◽  
Cell Wall Polysaccharide ◽  
Bacterial Cells ◽  
Content Type ◽  
Repeat Units ◽  
Undecaprenyl Phosphate

ABSTRACT Bacillus anthracis, the causative agent of anthrax disease, elaborates a secondary cell wall polysaccharide (SCWP) that is required for the retention of surface layer (S-layer) and S-layer homology (SLH) domain proteins. Genetic disruption of the SCWP biosynthetic pathway impairs growth and cell division. B. anthracis SCWP is comprised of trisaccharide repeats composed of one ManNAc and two GlcNAc residues with O-3–α-Gal and O-4–β-Gal substitutions. UDP-Gal, synthesized by GalE1, is the substrate of galactosyltransferases that modify the SCWP repeat. Here, we show that the gtsE gene, which encodes a predicted glycosyltransferase with a GT-A fold, is required for O-4–β-Gal modification of trisaccharide repeats. We identify a DXD motif critical for GtsE activity. Three distinct genes, gtsA, gtsB, and gtsC, are required for O-3–α-Gal modification of trisaccharide repeats. Based on the similarity with other three-component glycosyltransferase systems, we propose that GtsA transfers Gal from cytosolic UDP-Gal to undecaprenyl phosphate (C55-P), GtsB flips the C55-P-Gal intermediate to the trans side of the membrane, and GtsC transfers Gal onto trisaccharide repeats. The deletion of galE1 does not affect growth in vitro, suggesting that galactosyl modifications are dispensable for the function of SCWP. The deletion of gtsA, gtsB, or gtsC leads to a loss of viability, yet gtsA and gtsC can be deleted in strains lacking galE1 or gtsE. We propose that the loss of viability is caused by the accumulation of undecaprenol-bound precursors and present an updated model for SCWP assembly in B. anthracis to account for the galactosylation of repeat units. IMPORTANCE Peptidoglycan is a conserved extracellular macromolecule that protects bacterial cells from turgor pressure. Peptidoglycan of Gram-positive bacteria serves as a scaffold for the attachment of polymers that provide defined bacterial interactions with their environment. One such polymer, B. anthracis SCWP, is pyruvylated at its distal end to serve as a receptor for secreted proteins bearing the S-layer homology domain. Repeat units of SCWP carry three galactoses in B. anthracis. Glycosylation is a recurring theme in nature and often represents a means to mask or alter conserved molecular signatures from intruders such as bacteriophages. Several glycosyltransferase families have been described based on bioinformatics prediction, but few have been studied. Here, we describe the glycosyltransferases that mediate the galactosylation of B. anthracis SCWP.

scholarly journals Galactosylation of the Secondary Cell Wall Polysaccharide ofBacillus anthracisand Its Contribution to Anthrax Pathogenesis

2017 ◽  
Vol 200 (5) ◽  
Author(s):  
Alice Chateau ◽  
Justin Mark Lunderberg ◽  
So Young Oh ◽  
Teresa Abshire ◽  
Arthur Friedlander ◽  
...  
Keyword(s):  
Cell Wall ◽  
Glutamic Acid ◽  
Bacillus Anthracis ◽  
Secondary Cell Wall ◽  
Cell Wall Polysaccharide ◽  
Wild Type ◽  
Content Type ◽  
Bacterial Inoculum ◽  
Associated Proteins

ABSTRACTBacillus anthracis, the causative agent of anthrax disease, elaborates a secondary cell wall polysaccharide (SCWP) that is essential for bacterial growth and cell division.B. anthracisSCWP is comprised of trisaccharide repeats with the structure, [→4)-β-ManNAc-(1→4)-β-GlcNAc(O3-α-Gal)-(1→6)-α-GlcNAc(O3-α-Gal,O4-β-Gal)-(1→]6-12. The genes whose products promote the galactosylation ofB. anthracisSCWP are not yet known. We show here that the expression ofgalE1, encoding a UDP-glucose 4-epimerase necessary for the synthesis of UDP-galactose, is required forB. anthracisSCWP galactosylation. ThegalE1mutant assembles surface (S) layer and S layer-associated proteins that associate with ketal-pyruvylated SCWP via their S layer homology domains similarly to wild-typeB. anthracis, but the mutant displays a defect in γ-phage murein hydrolase binding to SCWP. Furthermore, deletion ofgalE1diminishes the capsulation ofB. anthraciswith poly-d-γ-glutamic acid (PDGA) and causes a reduction in bacterial virulence. These data suggest that SCWP galactosylation is required for the physiologic assembly of theB. anthraciscell wall envelope and for the pathogenesis of anthrax disease.IMPORTANCEUnlike virulentBacillus anthracisisolates,B. anthracisstrain CDC684 synthesizes secondary cell wall polysaccharide (SCWP) trisaccharide repeats without galactosyl modification, exhibits diminished growthin vitroin broth cultures, and is severely attenuated in an animal model of anthrax. To examine whether SCWP galactosylation is a requirement for anthrax disease, we generated variants ofB. anthracisstrains Sterne 34F2 and Ames lacking UDP-glucose 4-epimerase by mutating the genesgalE1andgalE2. We identifiedgalE1as necessary for SCWP galactosylation. Deletion ofgalE1decreased the poly-d-γ-glutamic acid (PDGA) capsulation of the vegetative form ofB. anthracisand increased the bacterial inoculum required to produce lethal disease in mice, indicating that SCWP galactosylation is indeed a determinant of anthrax disease.

scholarly journals Bacillus anthracis Acetyltransferases PatA1 and PatA2 Modify the Secondary Cell Wall Polysaccharide and Affect the Assembly of S-Layer Proteins

2012 ◽  
Vol 195 (5) ◽  
pp. 977-989 ◽  
Author(s):  
J. M. Lunderberg ◽  
S.-M. Nguyen-Mau ◽  
G. S. Richter ◽  
Y.-T. Wang ◽  
J. Dworkin ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Anthracis ◽  
Secondary Cell Wall ◽  
Cell Wall Polysaccharide

scholarly journals Cardiolipin Alters Rhodobacter sphaeroides Cell Shape by Affecting Peptidoglycan Precursor Biosynthesis

mBio ◽  
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Ti-Yu Lin ◽  
William S. Gross ◽  
George K. Auer ◽  
Douglas B. Weibel
Keyword(s):  
Cell Wall ◽  
Rhodobacter Sphaeroides ◽  
Cell Morphology ◽  
Cell Shape ◽  
Molecular Mechanisms ◽  
Wild Type ◽  
Anionic Phospholipid ◽  
Content Type ◽  
Lipid Ii ◽  
Topological Features

ABSTRACT Cardiolipin (CL) is an anionic phospholipid that plays an important role in regulating protein biochemistry in bacteria and mitochondria. Deleting the CL synthase gene (Δcls) in Rhodobacter sphaeroides depletes CL and decreases cell length by 20%. Using a chemical biology approach, we found that a CL deficiency does not impair the function of the cell wall elongasome in R. sphaeroides; instead, biosynthesis of the peptidoglycan (PG) precursor lipid II is decreased. Treating R. sphaeroides cells with fosfomycin and d-cycloserine inhibits lipid II biosynthesis and creates phenotypes in cell shape, PG composition, and spatial PG assembly that are strikingly similar to those seen with R. sphaeroides Δcls cells, suggesting that CL deficiency alters the elongation of R. sphaeroides cells by reducing lipid II biosynthesis. We found that MurG—a glycosyltransferase that performs the last step of lipid II biosynthesis—interacts with anionic phospholipids in native (i.e., R. sphaeroides) and artificial membranes. Lipid II production decreases 25% in R. sphaeroides Δcls cells compared to wild-type cells, and overexpression of MurG in R. sphaeroides Δcls cells restores their rod shape, indicating that CL deficiency decreases MurG activity and alters cell shape. The R. sphaeroides Δcls mutant is more sensitive than the wild-type strain to antibiotics targeting PG synthesis, including fosfomycin, d-cycloserine, S-(3,4-dichlorobenzyl)isothiourea (A22), mecillinam, and ampicillin, suggesting that CL biosynthesis may be a potential target for combination chemotherapies that block the bacterial cell wall. IMPORTANCE The phospholipid composition of the cell membrane influences the spatial and temporal biochemistry of cells. We studied molecular mechanisms connecting membrane composition to cell morphology in the model bacterium Rhodobacter sphaeroides. The peptidoglycan (PG) layer of the cell wall is a dominant component of cell mechanical properties; consequently, it has been an important antibiotic target. We found that the anionic phospholipid cardiolipin (CL) plays a role in determination of the shape of R. sphaeroides cells by affecting PG precursor biosynthesis. Removing CL in R. sphaeroides alters cell morphology and increases its sensitivity to antibiotics targeting proteins synthesizing PG. These studies provide a connection to spatial biochemical control in mitochondria, which contain an inner membrane with topological features in common with R. sphaeroides.

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