scholarly journals Evidence for involvement of IgA1 hinge glycopeptide in the IgA1-IgA1 interaction in IgA nephropathy.

1997 ◽  
Vol 8 (6) ◽  
pp. 915-919 ◽  
Author(s):  
T Kokubo ◽  
Y Hiki ◽  
H Iwase ◽  
A Horii ◽  
A Tanaka ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Iga Nephropathy ◽  
Binding Sites ◽  
Competitive Inhibition ◽  
Hinge Region ◽  
Percent Inhibition ◽  
The Core ◽  
Proline Rich Peptide ◽  
Inhibition Curve

The study was performed to investigate the role of the IgA1 hinge region in the IgA1-IgA1 interaction, which was observed previously in IgA nephropathy. The competitive inhibition assays of the IgA1-IgA1 binding were performed using the following candidates for inhibitors: native IgA1 hinge glycopeptide (nHGP), IgA1, IgA2, and IgG. The IgA1-IgA1 binding was definitely inhibited by the nHGP and the IgA1 (maximum of percent inhibition: 66.1 and 60.5%, respectively). There was no obvious inhibition in the IgA2 and the IgG. The inhibition curves of the nHGP and the IgA1 were significantly different from that of the IgG (P < 0.01, respectively). Furthermore, to reveal the detailed binding sites in the interaction, the same inhibition assays were performed using the following substances composing the IgA1 hinge glycopeptide: galactose (Gal), N-acetyl-galactosamine (GalNAc), Gal beta 1-3GalNAc, sialic acid, tetrapeptide PTPS, and synthesized hinge proline-rich peptide PVPSTPPTPSPSTPPTPSPS (sHP). sHP, Gal beta 1-3GalNAc, Gal, and GalNAc inhibited the binding (69.3, 34.1, 14.9, 14.6%, respectively). No obvious inhibition was observed in sialic acid and tetrapeptide PTPS. The inhibition curve of sHP was significantly different from that of the PTPS (P < 0.05). Those of Gal beta 1-3GalNAc, Gal, and GalNAc were also significantly different from that of sialic acid (P < 0.05, respectively). These results suggested that the IgA1-IgA1 interaction could be mediated by the core structure including the peptide and the sugars, except for sialic acid in the hinge region, resulting in the formation of the circulating macromolecular IgA1 in IgA nephropathy.

scholarly journals Humoral immunity against the proline-rich peptide epitope of the IgA1 hinge region in IgA nephropathy

2000 ◽  
Vol 15 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Tohru Kokubo ◽  
Kenjiro Hashizume ◽  
Hitoo Iwase ◽  
Kenji Arai ◽  
Atsushi Tanaka ◽  
...  
Keyword(s):  
Iga Nephropathy ◽  
Humoral Immunity ◽  
Hinge Region ◽  
Peptide Epitope ◽  
Proline Rich Peptide

scholarly journals Binding studies of a sialic acid-specific lectin from the horseshoe crab Carcinoscorpius rotunda cauda with various sialoglycoproteins

1982 ◽  
Vol 203 (1) ◽  
pp. 253-261 ◽  
Author(s):  
S Mohan ◽  
D Thambi Dorai ◽  
S Srimal ◽  
B K Bachhawat
Keyword(s):  
Sialic Acid ◽  
Binding Sites ◽  
Horseshoe Crab ◽  
Binding Studies ◽  
Sialic Acid Content ◽  
Precipitation Inhibition ◽  
Bivalent Metal Ions ◽  
Acidic Sugars ◽  
Inhibition Studies

Interaction of the sialic acid-specific lectin carcinoscorpin with various sialoglycoproteins was studied by using radioiodinated lectin. The binding of carcinoscorpin was dependent not only on sialic acid content but also on the type of glycosidic linkage and form (branched or linear) of the carbohydrate chains. Carcinoscorpin has different classes of binding sites, and binding follows a phenomenon of positive co-operativity. The effect of Ca2+ concentration on the binding was studied, and the optimal concentration was found to be 0.02 M. Effect of pH, temperature and other bivalent metal ions are also reported. From haemagglutination- and precipitation-inhibition studies, it was concluded that carcinoscorpin has multispecificity towards acidic sugars, and its relation to the biological role of the lectin in the horseshoe crab is discussed.

scholarly journals Glycophorin A interferes in the agglutination of human erythrocytes by concanavalin A Explanation of the requirement for enzymic predigestion

1987 ◽  
Vol 241 (2) ◽  
pp. 505-511 ◽  
Author(s):  
S M Gokhale ◽  
N G Mehta
Keyword(s):  
Sialic Acid ◽  
Correlation Coefficient ◽  
Concanavalin A ◽  
Binding Sites ◽  
Band 3 ◽  
Human Erythrocytes ◽  
The Other ◽  
Glycophorin A ◽  
Con A

Human erythrocytes become agglutinable with concanavalin A (Con A) after treatment with various proteinases or neuraminidase. The extent of agglutinability achieved with different enzymes is, however, different: Pronase, papain, trypsin, neuraminidase and chymotrypsin enhance the agglutinability in decreasing order, the last being barely effective. The actions of the enzymes on band 3, the Con A receptor, do not correlate with their abilities to increase the agglutinability: Pronase, papain and chymotrypsin cleave the protein, but not trypsin or neuraminidase. No significant differences are found in the number of Con A-binding sites or the affinities for the lectin between the normal and trypsin- or Pronase-treated cells. Thus the receptor does not seem to play a role in determining the Con A-agglutinability of erythrocytes. On the other hand, the cleavage of glycophorins, especially glycophorin A, and the release of sialic acid (in the peptide-bound form) are well-correlated with the enhancement in agglutination after the action of proteinases. The release of sialic acid by graded neuraminidase digestion and the increase in Con A-agglutinability show a correlation coefficient of 0.88. The major inhibitory role of glycophorin A in the process is indicated by the agglutination of En(a) heterozygous erythrocytes; the cells, known to bear about 50% glycophorin A molecules in their membrane, are agglutinated approximately half as well without proteolysis as are the trypsin-treated cells. Possible mechanisms by which glycophorin A could affect Con A-mediated agglutination are discussed.

scholarly journals Role of the histone amino termini in facilitated binding of a transcription factor, GAL4-AH, to nucleosome cores.

1994 ◽  
Vol 14 (2) ◽  
pp. 970-981 ◽  
Author(s):  
M Vettese-Dadey ◽  
P Walter ◽  
H Chen ◽  
L J Juan ◽  
J L Workman
Keyword(s):  
Dna Binding ◽  
Binding Sites ◽  
Core Histone ◽  
Nucleosome Core ◽  
Naked Dna ◽  
The Core ◽  
Nucleosomal Dna ◽  
Multiple Binding Sites ◽  
Multiple Binding

Facilitated, "cooperative" binding of GAL4-AH to nucleosomal DNA occurred in response to inhibition from the core histone amino termini. The binding of GAL4-AH (which contains the DNA-binding and dimerization domains of GAL4) to nucleosome cores containing multiple binding sites initiated at the end of a nucleosome core and proceeded in a cooperative manner until all sites were occupied. However, following tryptic removal of the core histone amino termini, GAL4-AH binding appeared to be noncooperative, similar to binding naked DNA. Binding of GAL4-AH to nucleosomes bearing a single GAL4 site at different positions indicated that inhibition of GAL4 binding was largely mediated by the histone amino termini and primarily occurred at sites well within the core and not near the end. When the histone amino termini were intact, binding of GAL4-AH to sites near the center of a nucleosome core was greatly enhanced by the presence of additional GAL4 dimers bound to more-accessible positions. These data illustrate that the binding of a factor to more-accessible sites, near the end of a nucleosome, allows facilitated binding of additional factors to the center of the nucleosome, thereby overcoming repression from the core histone amino termini. This mechanism may contribute to the binding of multiple factors to complex promoter and enhancer elements in cellular chromatin.

scholarly journals Role of sialic acids in feline enteric coronavirus infections

2014 ◽  
Vol 95 (9) ◽  
pp. 1911-1918 ◽  
Author(s):  
Lowiese M. B. Desmarets ◽  
Sebastiaan Theuns ◽  
Inge D. M. Roukaerts ◽  
Delphine D. Acar ◽  
Hans J. Nauwynck
Keyword(s):  
Sialic Acid ◽  
Competitive Inhibition ◽  
Binding Capacity ◽  
Binding Activity ◽  
Sialic Acids ◽  
Intestinal Epithelial ◽  
Virus Receptor ◽  
Knowing That ◽  
Sialic Acid Binding

To initiate infections, many coronaviruses use sialic acids, either as receptor determinants or as attachment factors helping the virus find its receptor underneath the heavily glycosylated mucus layer. In the present study, the role of sialic acids in serotype I feline enteric coronavirus (FECV) infections was studied in feline intestinal epithelial cell cultures. Treatment of cells with neuraminidase (NA) enhanced infection efficiency, showing that terminal sialic acid residues on the cell surface were not receptor determinants and even hampered efficient virus–receptor engagement. Knowing that NA treatment of coronaviruses can unmask viral sialic acid binding activity, replication of untreated and NA-treated viruses was compared, showing that NA treatment of the virus enhanced infectivity in untreated cells, but was detrimental in NA-treated cells. By using sialylated compounds as competitive inhibitors, it was demonstrated that sialyllactose (2,6-α-linked over 2,3-α-linked) notably reduced infectivity of NA-treated viruses, whereas bovine submaxillary mucin inhibited both treated and untreated viruses. In desialylated cells, however, viruses were less prone to competitive inhibition with sialylated compounds. In conclusion, this study demonstrated that FECV had a sialic acid binding capacity, which was partially masked by virus-associated sialic acids, and that attachment to sialylated compounds could facilitate enterocyte infections. However, sialic acid binding was not a prerequisite for the initiation of infection and virus–receptor engagement was even more efficient after desialylation of cells, indicating that FECV requires sialidases for efficient enterocyte infections.

scholarly journals Sperm Binding to Oviductal Epithelial Cells in the Rat: Role of Sialic Acid Residues on the Epithelial Surface and Sialic Acid-Binding Sites on the Sperm Surface1

2004 ◽  
Vol 71 (4) ◽  
pp. 1262-1269 ◽  
Author(s):  
Paula P. Cortés ◽  
Pedro A. Orihuela ◽  
Lidia M. Zúñiga ◽  
Luis A. Velásquez ◽  
Horacio B. Croxatto
Keyword(s):  
Sialic Acid ◽  
Epithelial Cells ◽  
Binding Sites ◽  
Epithelial Surface ◽  
Sperm Binding ◽  
Sialic Acid Binding

scholarly journals Role of Secondary Sialic Acid Binding Sites in Influenza N1 Neuraminidase

2010 ◽  
Vol 132 (9) ◽  
pp. 2883-2885 ◽  
Author(s):  
Jeffrey C. Sung ◽  
Adam W. Van Wynsberghe ◽  
Rommie E. Amaro ◽  
Wilfred W. Li ◽  
J. Andrew McCammon
Keyword(s):  
Sialic Acid ◽  
Binding Sites ◽  
Sialic Acid Binding

scholarly journals Competitive Cooperation of Hemagglutinin and Neuraminidase during Influenza A Virus Entry

Viruses ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 458 ◽  
Author(s):  
Ruikun Du ◽  
Qinghua Cui ◽  
Lijun Rong
Keyword(s):  
Sialic Acid ◽  
Influenza A Virus ◽  
Binding Sites ◽  
Influenza A ◽  
Virus Entry ◽  
Progeny Virus ◽  
Virus Attachment ◽  
Infected Cells ◽  
Competitive Cooperation

The hemagglutinin (HA) and neuraminidase (NA) of influenza A virus possess antagonistic activities on interaction with sialic acid (SA), which is the receptor for virus attachment. HA binds SA through its receptor-binding sites, while NA is a receptor-destroying enzyme by removing SAs. The function of HA during virus entry has been extensively investigated, however, examination of NA has long been focused to its role in the exit of progeny virus from infected cells, and the role of NA in the entry process is still under-appreciated. This review summarizes the current understanding of the roles of HA and NA in relation to each other during virus entry.

Sign in / Sign up

Export Citation Format

Share Document