Streptococcus mutans SMU.623c codes for a functional, metal-dependent polysaccharide deacetylase that modulates interactions with salivary agglutinin. / Deng, Dong Mei; Urch, Jonathan E.; ten Cate, Jacob M.; Rao, Vincenzo A.; van Aalten, Daan M. F.; Crielaard, Wim.
In: Journal of Bacteriology, Vol. 191, No. 1, 01.2009, p. 394-402.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Streptococcus mutans SMU.623c codes for a functional, metal-dependent polysaccharide deacetylase that modulates interactions with salivary agglutinin
A1 - Deng,Dong Mei
A1 - Urch,Jonathan E.
A1 - ten Cate,Jacob M.
A1 - Rao,Vincenzo A.
A1 - van Aalten,Daan M. F.
A1 - Crielaard,Wim
AU - Deng,Dong Mei
AU - Urch,Jonathan E.
AU - ten Cate,Jacob M.
AU - Rao,Vincenzo A.
AU - van Aalten,Daan M. F.
AU - Crielaard,Wim
PY - 2009/1
Y1 - 2009/1
N2 - <p>The genome sequence of the oral pathogen Streptococcus mutans predicts the presence of two putative polysaccharide deacetylases. The first, designated PgdA in this paper, shows homology to the catalytic domains of peptidoglycan deacetylases from Streptococcus pneumoniae and Listeria monocytogenes, which are both thought to be involved in the bacterial defense mechanism against human mucosal lysozyme and are part of the CAZY family 4 carbohydrate esterases. S. mutans cells in which the pgdA gene was deleted displayed a different colony texture and a slightly increased cell surface hydrophobicity and yet did not become hypersensitive to lysozyme as shown previously for S. pneumoniae. To understand this apparent lack of activity, the high-resolution X-ray structure of S. mutans PgdA was determined; it showed the typical carbohydrate esterase 4 fold, with metal bound in a His-His-Asp triad. Analysis of the protein surface showed that an extended groove lined with aromatic residues is orientated toward the active-site residues. The protein exhibited metal-dependent de-N-acetylase activity toward a hexamer of N-acetylglucosamine. No activity was observed toward shorter chitooligosaccharides or a synthetic peptidoglycan tetrasaccharide. In agreement with the lysozyme data this would suggest that S. mutans PgdA does not act on peptidoglycan but on an as-yet-unidentified polysaccharide within the bacterial cell surface. Strikingly, the pgdA-knockout strain showed a significant increase in aggregation/agglutination by salivary agglutinin, in agreement with this gene acting as a deacetylase of a cell surface glycan.</p>
AB - <p>The genome sequence of the oral pathogen Streptococcus mutans predicts the presence of two putative polysaccharide deacetylases. The first, designated PgdA in this paper, shows homology to the catalytic domains of peptidoglycan deacetylases from Streptococcus pneumoniae and Listeria monocytogenes, which are both thought to be involved in the bacterial defense mechanism against human mucosal lysozyme and are part of the CAZY family 4 carbohydrate esterases. S. mutans cells in which the pgdA gene was deleted displayed a different colony texture and a slightly increased cell surface hydrophobicity and yet did not become hypersensitive to lysozyme as shown previously for S. pneumoniae. To understand this apparent lack of activity, the high-resolution X-ray structure of S. mutans PgdA was determined; it showed the typical carbohydrate esterase 4 fold, with metal bound in a His-His-Asp triad. Analysis of the protein surface showed that an extended groove lined with aromatic residues is orientated toward the active-site residues. The protein exhibited metal-dependent de-N-acetylase activity toward a hexamer of N-acetylglucosamine. No activity was observed toward shorter chitooligosaccharides or a synthetic peptidoglycan tetrasaccharide. In agreement with the lysozyme data this would suggest that S. mutans PgdA does not act on peptidoglycan but on an as-yet-unidentified polysaccharide within the bacterial cell surface. Strikingly, the pgdA-knockout strain showed a significant increase in aggregation/agglutination by salivary agglutinin, in agreement with this gene acting as a deacetylase of a cell surface glycan.</p>
KW - N-acetylglucosamine deacetylase
KW - Biofilm formation
KW - Cryptococcus neoformans
KW - Bacteria binding
KW - Virulence factor
KW - Peptidoglycan
KW - System
KW - Protein
KW - Pathogen
KW - Chitin
U2 - 10.1128/JB.00838-08
DO - 10.1128/JB.00838-08
M1 - Article
JO - Journal of Bacteriology
JF - Journal of Bacteriology
SN - 0021-9193
IS - 1
VL - 191
SP - 394
EP - 402
ER -