Bacillus anthracis Surface-Layer Proteins Assemble by Binding to the Secondary Cell Wall Polysaccharide in a Manner that Requires csaB and tagO

Kern, Justin W.; Ryan, Christopher M.; Faull, Kym F.; Schneewind, Olaf

doi:10.1016/j.jmb.2010.06.059

Cited by 72 publications

(134 citation statements)

References 32 publications

Supporting

Mentioning

132

Contrasting

Order By: Relevance

“…The SCWP is modified with ketal-pyruvyl and acetyl groups, which enable assembly of the bacterial surface (S)-layer and its S-layer-associated proteins (12). The genetic determinants for SCWP modification are known; however, they are neither required for vegetative growth, nor do they contribute to the bacterial cell cycle (13,14). Murein linkage units, formed via TagO-and TagA-mediated assembly of undecaprenol-(PO 4 ) 2 -GlcNAc-ManNAc, function as an assembly platform for WTA precursors that, once translocated across the membrane, are tethered by LytR-CpsA-Psr (LCP) enzymes via a phosphodiester linkage to the C-6 hydroxyl of N-acetylmuramic acid (MurNAc) in the glycan strands of peptidoglycan (5,10,15).…”

mentioning

confidence: 99%

“…Murein linkage units, formed via TagO-and TagA-mediated assembly of undecaprenol-(PO 4 ) 2 -GlcNAc-ManNAc, function as an assembly platform for WTA precursors that, once translocated across the membrane, are tethered by LytR-CpsA-Psr (LCP) enzymes via a phosphodiester linkage to the C-6 hydroxyl of N-acetylmuramic acid (MurNAc) in the glycan strands of peptidoglycan (5,10,15). B. anthracis expression of tagO is essential for vegetative growth and contributes to SCWP assembly, which also involves the lcpB1 to -4 (lcpB1-4), lcpC, and lcpD genes of this microbe (13,16,17).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Genes Required for Bacillus anthracis Secondary Cell Wall Polysaccharide Synthesis

Lunderberg

Château

et al. 2017

J Bacteriol

Self Cite

View full text Add to dashboard Cite

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)-␤-ManNAc-(1¡4)-␤-GlcNAc-(1¡6)-␣-GlcNAc-(1¡) with ␣-Gal and ␤-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.KEYWORDS Bacillus anthracis, S-layers, Wzy repeat polymerase, cell wall polysaccharide, envelope assembly T he peptidoglycan cell wall of Gram-positive microbes is a determinant of bacterial shape and integrity (1, 2). Peptidoglycan also serves as a scaffold for the attachment of secondary polymers, which support specific cell cycle functions of bacteria (3, 4). Some Gram-positive bacteria, for example, Bacillus subtilis and Staphylococcus aureus, attach wall teichoic acid (WTA) to peptidoglycan, thereby positioning peptidoglycan synthesis enzymes, division septa, and murein hydrolases for cell growth and division (5-7). Other microbes, including Streptococcus species and Bacillus cereus, attach a secondary cell wall polysaccharide (SCWP) to peptidoglycan, and these polymers presumably fulfill functions similar to that of WTA during the bacterial cell cycle (8, 9). While WTA synthesis has been studied in detail (10), little is known about the genetic determinants and assembly reactions for SCWP synthesis.

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

Genes Required for Bacillus anthracis Secondary Cell Wall Polysaccharide Synthesis

Lunderberg

Château

et al. 2017

J Bacteriol

Self Cite

View full text Add to dashboard Cite

show abstract

“…Hallmarks of pathogenic Bacillus species are virulence plasmids, pXO-1 and pXO-2 in B. anthracis (8,9), providing for toxin production and capsulation (10,11) as well as the chromosomally encoded surface (S)-layer locus (12). Two S-layer proteins of B. anthracis, Sap and EA1, are endowed with S-layer homology (SLH) domains, which retain these proteins in the bacterial envelope by binding to the secondary cell wall polysaccharide (SCWP) (13)(14)(15). S-layer protein crystallization domains, responsible for the spontaneous assembly of these polypeptides into a paracrystalline array (16), form a twodimensional lattice that can be thought of as bacterial integument (17)(18)(19).…”

mentioning

confidence: 99%

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

et al. 2014

Self Cite

View full text Add to dashboard Cite

bBacillus 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 the B. anthracis lcpD mutant, which displays increased chain length and S-layer assembly defects due to diminished SCWP attachment to peptidoglycan. In contrast, the B. anthracis lcpB3 variant 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. anthracis does not synthesize these polymers, yet its genome encodes six LCP homologues, which, when expressed in S. aureus, promote WTA attachment. We propose a model whereby B. anthracis LCPs promote attachment of SCWP precursors to discrete locations in the peptidoglycan, enabling BSL assembly and regulated separation of septal peptidoglycan. Bacillus anthracis, the causative agent of anthrax, is a sporeforming, Gram-positive bacterium that germinates in host infected tissues and replicates as elongated chains of vegetative forms (1, 2). This unique growth pattern appears to be caused by the regulated separation of septal peptidoglycan, which generates bacterial chains whose mere size precludes clearance by host phagocytes (3-5). The genetic determinants for B. anthracis chain formation are conserved among pathogenic species of the Bacillus cereus group and, as demonstrated with B. cereus G9241, likely contribute to disease pathogenesis (6, 7). Hallmarks of pathogenic Bacillus species are virulence plasmids, pXO-1 and pXO-2 in B. anthracis (8, 9), providing for toxin production and capsulation (10, 11) as well as the chromosomally encoded surface (S)-layer locus (12). Two S-layer proteins of B. anthracis, Sap and EA1, are endowed with S-layer homology (SLH) domains, which retain these proteins in the bacterial envelope by binding to the secondary cell wall polysaccharide (SCWP) (13-15). S-layer protein crystallization domains, responsible for the spontaneous assembly of these polypeptides into a paracrystalline array (16), form a twodimensional lattice that can be thought of as bacterial integument (17)(18)(19).The structural genes of S-layer proteins, sap and eag, are flanked by genes encoding determinants for S-layer protein secretion (secA2 and slaP) (12) or pyruvylation (csaB) (14) as well as acetylation of the SCWP (patA1/2 and patB1/2) (20). CsaB-mediated pyruvylation of the terminal N-acetylmannosamine (ManNAc) of the SCWP (21), with the repeat struc- (22), is a prerequisite for the assembly of S-layer proteins and 22 B. anthracis S-layer-associated proteins (BSLs) (14). PatAB1/2-mediated acetylation of SCWP molecules affects the assembly of EA1 and of some but not all BSLs (20). Recent studies have begun to identify genes for SCWP synthesis, which, unlike py...

show abstract

“…Insertional lesions in bslO, sap, and csaB, as well as patA1 and patA2, increase the chain lengths of B. anthracis vegetative forms without affecting the size of bacterial cells (15)(16)(17)(18). bslO encodes a secreted cell wall hydrolase with S-layer homology (SLH) domains that bind to pyruvylated secondary cell wall polysaccharide (SCWP) (15), comprised of the repeating unit [¡4)-␤-ManNAc-(1¡4)-␤-GlcNAc-(1¡6)-␣-GlcNAc-(1¡)] n (19,20).…”

mentioning

confidence: 99%

“…B. anthracis variants lacking the S-layer protein Sap cannot restrict BslO localization to septal rings; similar to bslO mutants, sap variants form elongated chains of vegetative bacilli (16). csaB mutants display the most severe cell separation defect, and the variants are unable to deposit any S-layer or S-layer-associated proteins with SLH domains in the envelope of B. anthracis (17,21). csaB is thought to encode a pyruvyl transferase that transfers ketal-pyruvyl onto the terminal ␤-ManNAc residue at the distal end of the SCWP (20).…”

mentioning

confidence: 99%

Bacillus anthracis SlaQ Promotes S-Layer Protein Assembly

Nguyen-Mau

Schneewind

et al. 2015

J Bacteriol

Self Cite

View full text Add to dashboard Cite

Bacillus anthracis vegetative forms assemble an S-layer comprised of two S-layer proteins, Sap and EA1. A hallmark of S-layer proteins are their C-terminal crystallization domains, which assemble into a crystalline lattice once these polypeptides are deposited on the bacterial surface via association between their N-terminal S-layer homology domains and the secondary cell wall polysaccharide. Here we show that slaQ, encoding a small cytoplasmic protein conserved among pathogenic bacilli elaborating S-layers, is required for the efficient secretion and assembly of Sap and EA1. S-layer protein precursors cosediment with SlaQ, and SlaQ appears to facilitate Sap assembly. Purified SlaQ polymerizes and when mixed with purified Sap promotes the in vitro formation of tubular S-layer structures. A model is discussed whereby SlaQ, in conjunction with S-layer secretion factors SecA2 and SlaP, promotes localized secretion and S-layer assembly in B. anthracis. IMPORTANCES-layer proteins are endowed with the propensity for self-assembly into crystalline arrays. Factors promoting S-layer protein assembly have heretofore not been reported. We identified Bacillus anthracis SlaQ, a small cytoplasmic protein that facilitates S-layer protein assembly in vivo and in vitro.

show abstract

Bacillus anthracis Surface-Layer Proteins Assemble by Binding to the Secondary Cell Wall Polysaccharide in a Manner that Requires csaB and tagO

Cited by 72 publications

References 32 publications

Genes Required for Bacillus anthracis Secondary Cell Wall Polysaccharide Synthesis

Genes Required for Bacillus anthracis Secondary Cell Wall Polysaccharide Synthesis

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

Bacillus anthracis SlaQ Promotes S-Layer Protein Assembly

Contact Info

Product

Resources

About