Degradation of Heparan Sulfate by Nitrous Acid

2003 ◽  
pp. 347-351 ◽  
Author(s):  
H Edward Conrad
Keyword(s):  
2002 ◽  
Vol 277 (51) ◽  
pp. 49247-49255 ◽  
Author(s):  
Camilla Westling ◽  
Ulf Lindahl

Functional properties of heparan sulfate (HS) are generally ascribed to the sulfation pattern of the polysaccharide. However, recently reported functional implications of rareN-unsubstituted glucosamine (GlcNH2) residues in native HS prompted our structural characterization of sequences around such residues. HS preparations were cleaved with nitrous acid at eitherN-sulfated orN-unsubstituted glucosamine units followed by reduction with NaB3H4. The labeled products were characterized following complementary deamination steps. The proportion of GlcNH2units varied from 0.7–4% of total glucosamine in different HS preparations. The GlcNH2units occurred largely clustered at the polysaccharide-protein linkage region in intestinal HS, also more peripherally in aortic HS. They were preferentially located withinN-acetylated domains, or in transition sequences betweenN-acetylated andN-sulfated domains, only 20–30% of the adjacent upstream and downstream disaccharide units beingN-sulfated. The nearest downstream (toward the polysaccharide-protein linkage) hexuronic acid was invariably GlcUA, whereas the upstream neighbor could be either GlcUA or IdoUA. The highly sulfated butN-unsubstituted disaccharide unit, -IdoUA2S-GlcNH26S-, was detected in human renal and porcine intestinal HS, but not in HS from human aorta. These results are interpreted in terms of a biosynthetic mechanism, whereby GlcNH2residues are formed through regulated, incomplete action of anN-deacetylase/N-sulfotransferase enzyme.


Author(s):  
U. Frevert ◽  
S. Sinnis ◽  
C. Cerami ◽  
V. Nussenzweig

Malaria sporozoites, which invade hepatocytes within minutes after transmission by an infected mosquito, are covered with the circumsporozoite (CS) protein, which in all Plasmodium species contains the conserved region II-plus. This region is also found as a cell-adhesive motif in a variety of host proteins like thrombospondin, properdin and the terminal complement components.The CS protein with its region II-plus specifically binds to heparan sulfate proteoglycans (HSPG) on the basolateral surface of hepatocytes in the space of Disse (FIG. 1), to certain basolateral cell membranes and basement membranes of the kidney (FIG. 2) as well as to heparin in the granules of connective tissue mast cells. The distribution of the HSPG receptors for the CS protein was examined by incubation of Lowicryl K4M or LR White sections of liver and kidney tissue with the recombinant CS ligand, whose binding sites were detected with a monoclonal anti-CS antibody and protein A gold.


1996 ◽  
Vol 75 (01) ◽  
pp. 168-174 ◽  
Author(s):  
Shigeru Tokita ◽  
Morio Arai ◽  
Naomasa Yamamoto ◽  
Yasuhiro Katagiri ◽  
Kenjiro Tanoue ◽  
...  

SummaryTo study the pathological functions of anti-phospholipid (anti-PL) antibodies, we have analyzed their effect on platelet function. We identified an IgG anti-PL mAb, designated PSG3, which cross-reacted specifically with glycoprotein (GP) IIIa in human platelets and inhibited platelet aggregation. PSG3 bound also to certain polyanionic substances, such as double-stranded DNA, heparan sulfate, dextran sulfate and acetylated-LDL, but not to other polyanionic substances. The binding of PSG3 to GPIIIa was completely inhibited by heparan sulfate and dextran sulfate, indicating that PSG3 recognizes a particular array of negative charges expressed on both GPIIIa and the specified polyanionic substances. Since neither neuraminidase- nor endoglycopeptidase F-treatment of GPIIIa had any significant effect on the binding of PSG3, this array must be located within the amino acid sequence of GPIIIa but not in the carbohydrate moiety. Reduction of the disulfide bonds in GPIIIa greatly reduced its reactivity, suggesting that the negative charges in the epitope are arranged in a particular conformation. PSG3 inhibited platelet aggregation induced by either ADP or collagen, it also inhibited fibrinogen binding to activated platelets in a dose-dependent fashion. PSG3, however, did not inhibit the binding of GRGDSP peptide to activated platelets. These results suggest that the PSG3 epitope on GPIIIa contains a particular array of negative charges, and possibly affects the fibrinogen binding to GPIIb/IIIa complex necessary for platelet aggregation.


Diabetes ◽  
1982 ◽  
Vol 31 (2) ◽  
pp. 185-188 ◽  
Author(s):  
D. H. Rohrbach ◽  
J. R. Hassell ◽  
H. K. Kleinman ◽  
G. R. Martin

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