scholarly journals Characterization of O-Acetylation of N-Acetylglucosamine

2011 ◽  
Vol 286 (27) ◽  
pp. 23950-23958 ◽  
Author(s):  
Elvis Bernard ◽  
Thomas Rolain ◽  
Pascal Courtin ◽  
Alain Guillot ◽  
Philippe Langella ◽  
...  
Keyword(s):  
Cell Wall ◽  
Structural Characterization ◽  
Bacterial Species ◽  
Muramic Acid ◽  
Gram Positive Bacteria ◽  
Mutant Strains ◽  
Encoding Genes ◽  
Hydrolysis Of ◽  
Cell Wall Hydrolysis

Peptidoglycan (PG) N-acetyl muramic acid (MurNAc) O-acetylation is widely spread in Gram-positive bacteria and is generally associated with resistance against lysozyme and endogenous autolysins. We report here the presence of O-acetylation on N-acetylglucosamine (GlcNAc) in Lactobacillus plantarum PG. This modification of glycan strands was never described in bacteria. Fine structural characterization of acetylated muropeptides released from L. plantarum PG demonstrated that both MurNAc and GlcNAc are O-acetylated in this species. These two PG post-modifications rely on two dedicated O-acetyltransferase encoding genes, named oatA and oatB, respectively. By analyzing the resistance to cell wall hydrolysis of mutant strains, we showed that GlcNAc O-acetylation inhibits N-acetylglucosaminidase Acm2, the major L. plantarum autolysin. In this bacterial species, inactivation of oatA, encoding MurNAc O-acetyltransferase, resulted in marked sensitivity to lysozyme. Moreover, MurNAc over-O-acetylation was shown to activate autolysis through the putative N-acetylmuramoyl-l-alanine amidase LytH enzyme. Our data indicate that in L. plantarum, two different O-acetyltransferases play original and antagonistic roles in the modulation of the activity of endogenous autolysins.

scholarly journals AsnB Mediates Amidation of Meso-Diaminopimelic Acid Residues in the Peptidoglycan of Listeria monocytogenes and Affects Bacterial Surface Properties and Host Cell Invasion

2021 ◽  
Vol 12 ◽  
Author(s):  
Lei Sun ◽  
Gil Rogiers ◽  
Pascal Courtin ◽  
Marie-Pierre Chapot-Chartier ◽  
Hélène Bierne ◽  
...  
Keyword(s):  
Cell Wall ◽  
Listeria Monocytogenes ◽  
Cell Surface ◽  
Bacterial Species ◽  
Functional Characterization ◽  
Diaminopimelic Acid ◽  
Bacterial Surface ◽  
Gram Positive Bacteria ◽  
First Time

A mutant of Listeria monocytogenes ScottA with a transposon in the 5' untranslated region of the asnB gene was identified to be hypersensitive to the antimicrobial t-cinnamaldehyde. Here, we report the functional characterization of AsnB in peptidoglycan (PG) modification and intracellular infection. While AsnB of Listeria is annotated as a glutamine-dependent asparagine synthase, sequence alignment showed that this protein is closely related to a subset of homologs that catalyze the amidation of meso-diaminopimelic acid (mDAP) residues in the peptidoglycan of other bacterial species. Structural analysis of peptidoglycan from an asnB mutant, compared to that of isogenic wild-type (WT) and complemented mutant strains, confirmed that AsnB mediates mDAP amidation in L. monocytogenes. Deficiency in mDAP amidation caused several peptidoglycan- and cell surface-related phenotypes in the asnB mutant, including formation of shorter but thicker cells, susceptibility to lysozyme, loss of flagellation and motility, and a strong reduction in biofilm formation. In addition, the mutant showed reduced invasion of human epithelial JEG-3 and Caco-2 cells. Analysis by immunofluorescence microscopy revealed that asnB inactivation abrogated the proper display at the listerial surface of the invasion protein InlA, which normally gets cross-linked to mDAP via its LPXTG motif. Together, this work shows that AsnB of L. monocytogenes, like several of its homologs in related Gram-positive bacteria, mediates the amidation of mDAP residues in the peptidoglycan and, in this way, affects several cell wall and cell surface-related properties. It also for the first time implicates the amidation of peptidoglycan mDAP residues in cell wall anchoring of InlA and in bacterial virulence.

scholarly journals Characterization of Glycoside Hydrolase Family 5 Proteins in Schizosaccharomyces pombe

2010 ◽  
Vol 9 (11) ◽  
pp. 1650-1660 ◽  
Author(s):  
Encarnación Dueñas-Santero ◽  
Ana Belén Martín-Cuadrado ◽  
Thierry Fontaine ◽  
Jean-Paul Latgé ◽  
Francisco del Rey ◽  
...  
Keyword(s):  
Cell Wall ◽  
Schizosaccharomyces Pombe ◽  
Protein Characterization ◽  
Wall Material ◽  
Glycoside Hydrolase Family ◽  
Content Type ◽  
Hydrolysis Of ◽  
Controlled Hydrolysis ◽  
Hydrolase Family

ABSTRACT In yeast, enzymes with β-glucanase activity are thought to be necessary in morphogenetic events that require controlled hydrolysis of the cell wall. Comparison of the sequence of the Saccharomyces cerevisiae exo-β(1,3)-glucanase Exg1 with the Schizosaccharomyces pombe genome allowed the identification of three genes that were named exg1 + (locus SPBC1105.05), exg2 + (SPAC12B10.11), and exg3 + (SPBC2D10.05). The three proteins have different localizations: Exg1 is secreted to the periplasmic space, Exg2 is a membrane protein, and Exg3 is a cytoplasmic protein. Characterization of the biochemical activity of the proteins indicated that Exg1 and Exg3 are active only against β(1,6)-glucans while no activity was detected for Exg2. Interestingly, Exg1 cleaves the glucans with an endohydrolytic mode of action. exg1 + showed periodic expression during the cell cycle, with a maximum coinciding with the septation process, and its expression was dependent on the transcription factor Sep1. The Exg1 protein localizes to the septum region in a pattern that was different from that of the endo-β(1,3)-glucanase Eng1. Overexpression of Exg2 resulted in an increase in cell wall material at the poles and in the septum, but the putative catalytic activity of the protein was not required for this effect.

scholarly journals Functional and structural characterization of a novel putative cysteine protease cell wall-modifying multi-domain enzyme selected from a microbial metagenome

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Muhammad Faheem ◽  
Diogo Martins-de-Sa ◽  
Julia F. D. Vidal ◽  
Alice C. M. Álvares ◽  
José Brandão-Neto ◽  
...  
Keyword(s):  
Cell Wall ◽  
Structural Characterization ◽  
Cysteine Protease

scholarly journals Determination of amino sugars in mixtures containing glucosamine, galactosamine and muramic acid

1968 ◽  
Vol 109 (1) ◽  
pp. 13-18 ◽  
Author(s):  
D. E. S. Stewart-Tull
Keyword(s):  
Cell Wall ◽  
Quantitative Determination ◽  
Column Chromatography ◽  
Bacterial Species ◽  
Colorimetric Method ◽  
Previous Treatment ◽  
Amino Sugars ◽  
Muramic Acid ◽  
Molar Ratios

A colorimetric method is described whereby the direct quantitative determination of glucosamine, galactosamine and muramic acid can be achieved without previous treatment of the cell-wall hydrolysate, for example by column chromatography. Molar ratios of hexosamines in cell-wall preparations, from a number of bacterial species, determined by this method were found to be in general agreement with previously published results.

scholarly journals First Structural Characterization of a Bon-Domain in a Protein from Mycobacterium Tuberculosis: OmpATb Tracks toward an Oligomerization Process to form a Cell Wall Pore

2010 ◽  
Vol 98 (3) ◽  
pp. 648a
Author(s):  
Daniel Auguin ◽  
Yinshan Yang ◽  
Stephane Delbecq ◽  
Emilie Dumas ◽  
Virginie Molle ◽  
...  
Keyword(s):  
Cell Wall ◽  
Mycobacterium Tuberculosis ◽  
Structural Characterization ◽  
A Cell

New Preparations of Lignin Polymer Models under Conditions that Approximate Cell Wall Lignification. II. Structural Characterization of the Models by Thioacidolysis

Holzforschung ◽  
1996 ◽  
Vol 50 (1) ◽  
pp. 9-14 ◽  
Author(s):  
N. Terashima ◽  
R.H. Atalla ◽  
S.A. Ralph ◽  
L.L. Landucci ◽  
C. Lapierre ◽  
...  
Keyword(s):  
Cell Wall ◽  
Structural Characterization ◽  
Polymer Models

Synthesis and Structural Characterization of a Terminal Hydroxide Containing Alumoxane via Hydrolysis of Aluminum Hydrides

2004 ◽  
Vol 43 (4) ◽  
pp. 1217-1219 ◽  
Author(s):  
Ying Peng ◽  
Guangcai Bai ◽  
Hongjun Fan ◽  
Denis Vidovic ◽  
Herbert W. Roesky ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Aluminum Hydrides ◽  
Hydrolysis Of

scholarly journals MurF Inhibitors with Antibacterial Activity: Effect on Muropeptide Levels

2009 ◽  
Vol 53 (8) ◽  
pp. 3240-3247 ◽  
Author(s):  
Ellen Z. Baum ◽  
Steven M. Crespo-Carbone ◽  
Barbara D. Foleno ◽  
Lee D. Simon ◽  
Jerome Guillemont ◽  
...  
Keyword(s):  
Cell Wall ◽  
Pharmacophore Model ◽  
Polymyxin B ◽  
Bacterial Survival ◽  
Wild Type ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Activity Effect ◽  
Modest Activity

ABSTRACT MurF catalyzes the last cytoplasmic step of bacterial cell wall synthesis and is essential for bacterial survival. Our previous studies used a pharmacophore model of a MurF inhibitor to identify additional inhibitors with improved properties. We now present the characterization of two such inhibitors, the diarylquinolines DQ1 and DQ2. DQ1 inhibited Escherichia coli MurF (50% inhibitory concentration, 24 μM) and had modest activity (MICs, 8 to 16 μg/ml) against lipopolysaccharide (LPS)-defective E. coli and wild-type E. coli rendered permeable with polymyxin B nonapeptide. DQ2 additionally displayed activity against gram-positive bacteria (MICs, 8 to 16 μg/ml), including methicillin (meticillin)-susceptible and -resistant Staphylococcus aureus isolates and vancomycin-susceptible and -resistant Enterococcus faecalis and Enterococcus faecium isolates. Treatment of LPS-defective E. coli cells with ≥2× MIC of DQ1 resulted in a 75-fold-greater accumulation of the MurF substrate compared to the control, a 70% decline in the amount of the MurF product, and eventual cell lysis, consistent with the inhibition of MurF within bacteria. DQ2 treatment of S. aureus resulted in similar effects on the MurF substrate and product quantities. At lower levels of DQ1 (≤1× MIC), the level of accumulation of the substrate was less pronounced (15-fold greater compared to the amount for the control). However, a 50% increase in the amount of the MurF product compared to the control was reproducibly observed, consistent with the possible upregulation of muropeptide biosynthesis upon partial inhibition of this pathway. The overexpression of cloned MurF appeared to partly alleviate the DQ1-mediated inhibition of muropeptide synthesis. The identification of MurF inhibitors such as DQ1 and DQ2 that disrupt cell wall biosynthesis suggests that MurF remains a viable target for an antibacterial agent.

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