Structural Studies on Heparan Sulphates

Several microbial pathogens have been reported to interact with glycosaminoglycans (GAGs) on cell surfaces and in the extracellular matrix. Here we demonstrate that M protein, a major surface-expressed virulence factor of the human bacterial pathogen, Streptococcus pyogenes, mediates binding to various forms of GAGs. Hence, S. pyogenes strains expressing a large number of different types of M proteins bound to dermatan sulfate (DS), highly sulfated fractions of heparan sulfate (HS) and heparin, whereas strains deficient in M protein surface expression failed to interact with these GAGs. Soluble M protein bound DS directly and could also inhibit the interaction between DS and S. pyogenes. Experiments with M protein fragments and with streptococci expressing deletion constructs of M protein, showed that determinants located in the NH 2 -terminal part as well as in the C-repeat region of the streptococcal proteins are required for full binding to GAGs. Treatment with ABCchondroitinase and HS lyase that specifically remove DS and HS chains from cell surfaces, resulted in significantly reduced adhesion of S. pyogenes bacteria to human epithelial cells and skin fibroblasts. Together with the finding that exogenous DS and HS could inhibit streptococcal adhesion, these data suggest that GAGs function as receptors in M protein-mediated adhesion of S. pyogenes.

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“…. The preparation and characterization of these compounds have been described previously [33][34][35]. Heparin was purchased from Sigma.…”

Section: Proteins Gags Radiolabelling and Binding Assaymentioning

confidence: 99%

Interactions between M proteins of Streptococcus pyogenes and glycosaminoglycans promote bacterial adhesion to host cells

Frick¹,

Schmidtchen

Sjöbring

2003

European Journal of Biochemistry

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“…We report the selective removal of GlcA- p NP moiety from a more structurally complex heparin-like oligosaccharide using both Smith degradation and alkaline elimination 22–24 . This approach has been previously used for micro scale analysis of polysaccharides relying on mass spectrometry (MS) and leaves unnatural moieties at the reducing end of the resulting degradation products 25–28 . We have modified this method to prepare a natural heparin pentasaccharide rich in trisulfated disaccharide units.…”

mentioning

confidence: 99%

Chemoenzymatic synthesis of unmodified heparin oligosaccharides: cleavage of p-nitrophenyl glucuronide by alkaline and Smith degradation

Zhang

Hsieh

et al. 2017

Org. Biomol. Chem.

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A heparin oligosaccharide having a completely natural structure was successfully synthesized through a chemoenzymatic approach using an unnatural glycosyl acceptor, p-nitrophenyl glucuronide (GlcA-pNP). The use of an inexpensive and commercially available GlcA-pNP acceptor facilitates oligosaccharide recovery and purification on C-18 resin during chemoenzymatic synthesis. Oligosaccharide chain extension and modification afforded a heptasaccharide with gluconic acid residues at its reducing and non-reducing ends. Treatment with periodate oxidation followed by Smith degradation or alkaline elimination resulted in the selective cleavage of vicinal diol-containing glucronic acid residues affording highly sulfated heparin pentasaccharide having a completely natural structure. This methodology should facilitate the chemoenzymatic synthesis of a family of highly sulfated heparin oligosaccharides with unmodified structures for biological evaluation.

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Binding, internalization, and degradation of antiproliferative heparan sulfate by human embryonic lung fibroblasts

et al. 1997

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Binding, internalization, and degradation of 125I-labeled, antiproliferative, or nonantiproliferative heparan sulfate by human embryonic lung fibroblasts was investigated. Both L-iduronate-rich, antiproliferative heparan sulfate species as well as L-iduronate-poor, inactive ones were bound to trypsin-releasable, cell-surface sites. Both heparan sulfate types were bound with approximately the same affinity to one high-affinity site (Kd approximately 10(-8) M) and to one low-affinity site (Kd approximately 10(-6) M), respectively. Results of Hill-plot analysis suggested that the two sites are independent. Competition experiments with unlabeled glycosaminoglycans indicated that the binding sites had a selective specificity for sulfated, L-iduronate-rich heparan sulfate. Dermatan sulfate, which is also antiproliferative, was weakly bound to the cells. The antiproliferative effects of heparan and dermatan sulfate appeared to be additive. Hence, the two glycosaminoglycans probably exert their effect through different mechanisms. At concentrations above 5 micrograms/ml (approximately 10(-7) M), heparan sulfate was taken up by human embryonic lung fibroblasts, suggesting that the low-affinity site represents an endocytosis receptor. The antiproliferative effect of L-iduronate-rich heparan sulfate species was also exerted at the same concentrations. The antiproliferative species was taken up to a greater degree than the inactive one, suggesting a requirement for internalization. However, competition experiments with dextran sulfate suggested that both the high-affinity and the low-affinity sites are involved in mediating the antiproliferative effect. Structural analysis of the inactive and active heparan sulphate preparations indicated that although sulphated L-iduronate appears essential for antiproliferative activity, it is not absolutely required for binding to the cells. Degradation of internalized heparan sulfate was analyzed by polyacrylamide gel electrophoresis using a sensitive detection technique. The inactive species was partially degraded, whereas the antiproliferative one was only marginally affected.

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Structural Studies on Heparan Sulphates

Cited by 55 publications

References 30 publications

Interactions between M proteins of Streptococcus pyogenes and glycosaminoglycans promote bacterial adhesion to host cells

Interactions between M proteins of Streptococcus pyogenes and glycosaminoglycans promote bacterial adhesion to host cells

Chemoenzymatic synthesis of unmodified heparin oligosaccharides: cleavage of p-nitrophenyl glucuronide by alkaline and Smith degradation

Binding, internalization, and degradation of antiproliferative heparan sulfate by human embryonic lung fibroblasts

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