Search results for "glycoproteins"
showing 10 items of 496 documents
Intragenic G-quadruplex structure formed in the human CD133 and its biological and translational relevance.
2016
Cancer stem cells (CSCs) have been identified in several solid malignancies and are now emerging as a plausible target for drug discovery. Beside the questionable existence of CSCs specific markers, the expression of CD133 was reported to be responsible for conferring CSC aggressiveness. Here, we identified two G-rich sequences localized within the introns 3 and 7 of the CD133 gene able to form G-quadruplex (G4) structures, bound and stabilized by small molecules. We further showed that treatment of patient-derived colon CSCs with G4-interacting agents triggers alternative splicing that dramatically impairs the expression of CD133. Interestingly, this is strongly associated with a loss of C…
Description of a Simple, Specific, and Sensitive Test for the Detection of Detergent-Solubilized C3b Receptor
1981
Abstract The C3b receptor was isolated from detergent-solubilized human erythrocyte membranes by a previously described technique (1). The receptor glycoprotein was shown to enhance EAC14oxy23b rosette formation with Raji lymphoblastoid cells. This provided a specific and sensitive test to detect the solubilized C3b receptor either in crude or highly purified form. The property of the C3b receptor tested by this assay appears to be analogous to properties of β1H.
Role of glycosylation in the incorporation of intrinsic mannoproteins into cell walls of Saccharomyces cerevisiae.
1989
Cell wall mannoproteins from Saccharomyces cerevisiae are completely or partially incorporated into their final location when N-glycosylation is inhibited by tunicamycin. These include a 90–100 kDa species still containing O-linked oligomannose chains, derived from a N-glycosylated material larger than 120 kDa; and a 30.5 kDa peptide lacking mannose residues, derived from a 33 kDa species. For both species, the growth temperature influences the level of incorporation of the non N-glycosylated molecules. Secretion of the peptides lacking N-linked saccharide chains follows the route defined by sec mutants.
Sulfated and Non-Sulfated Glycopeptide Recognition Domains of P-Selectin Glycoprotein Ligand 1 and their Binding to P- and E-Selectin
2009
Total synthesis through block glycosylation and selective chemical O-sulfation of tyrosine residues yielded the glycopeptide recognition domain A (X=SO(3) (-)) of the P-selectin glycoprotein ligand 1, in which the terminal sialic acid of the complex hexasaccharide side chain was replaced by (S)-cyclohexyl lactic acid. In binding assays the O-sulfated structure A showed high affinity towards P-selectin, the non-sulfated towards E-selectin.
Loss of Contact-Dependent Inhibition of Growth in Chemically Transformed Fibroblasts
1988
The plasma membrane has been recognized as an important regulatory unit of mammalian cells during determination, differentiation, and social behaviour of individual cells within various tissues (1–4). On the molecular level, plasma membrane glycoproteins and glycolipids have been shown to be involved in these processes (1–4). Density-dependent growth of non-transformed cells in vitro has been proposed to be regulated by secreted inhibitory compounds (5–7), by the cell’s shape (8) or by diffusion boundary layers (9). On the other hand, specific cell-cell interactions via cell membrane molecules were found to be of great importance for the contact-dependent inhibition of growth (10–16) and co…
Xenograft rejection in marine sponges. Isolation and purification of an inhibitory aggregation factor from Geodia cydonium.
1981
In sponges there exists a graft rejection mechanism in which an inhibitory aggregation factor is involved. The inhibitory aggregation factor has been isolated from a culture medium containing dissociated cells of the sponge Geodia cydonium. Using ion-exchange and gel fractionation the factor was purified and shown to be electrophoretically pure. The factor has a molecular weight of 27000 and was characterized as a glycoprotein. The activity of the inhibitory aggregation factor was not affected by heat treatment, but treatment with trichloroacetic acid resulted in the irreversible loss of activity. The inhibitory aggregation factor affects the aggregation-factor-mediated reaggregation of dis…
Synthesis of β-d-mannosides from β-d-glucosides via an intramolecular Sn2 reaction at C-2
1992
Abstract The selective synthesis of β- d -mannosides was achieved by first synthesizing β- d -glucosides that carry a N -phenylcarbamoyl protecting group at O-3. These derivatives were transformed into the corresponding β- d -mannosides by intramolecular nucleophilic substitution with inversion of configuration at C-2, the O -triflyl group being the leaving group. Subsequent intramolecular attack of the neighboring carbamoyl group resulted in the formation of the 2,3-carbonate of the desired β d -mannoside.
Wall mannoproteins of the yeast and mycelial cells of Candida albicans: nature of the glycosidic bonds and polydispersity of their mannan moieties.
1988
SUMMARY: Zymolyase released between 20 and 25% of the total protein from purified walls of yeast (Y) and mycelial (M) cells of Candida albicans. The material released contained 92% carbohydrate (86% mannose and 6% glucose) and 7:< protein. Over 85% of the carbohydrate was N-glycosidically linked to the protein and the rest (less than 15%) was linked O-glycosidically. Highly polydisperse, high molecular mass mannoproteins, resolved by electrophoresis as four defined bands in Y cells and two bands in M cells, had both types of sugar chains. A 34 kDa species found in both types of cells had a single 2.5 kDa N-glycosidically linked sugar chain and a 3 1.5 kDa protein moiety. Polydispersity in t…
Structural mannoproteins released by β-elimination fromCandida albicanscell walls
1994
Abstract Mild alkaline solutions (β-elimination), after removing the non-covalently bonded wall materials by hot SDS, released 13% and 26% of remaining wall proteins from mycelial and yeast cells of Candida albicans, respectively. When the β-elimination was carried out after digestion of the walls with chitinase, four-fold more proteinaceous materials were released from mycelium and a similar amount in yeast walls. The solubilized materials were shown to be highly polydisperse, and endo-glycosidase H reduced their polydispersity and molecular masses, revealing different electrophoretic patterns in yeast and mycelial cell walls. The solubilized mycelial proteins carried N-glycosidic sugar ch…
Membrane oligo- and polysialic acids
2011
AbstractPolysialic acid (polySia) and oligosialic acid (oligoSia) chains are linear polysaccharides composed of sialic acid monomers. The majority of biological poly/oligoSia chains are bound to membranes. There is a large diversity of membrane poly/oligoSia in terms of chain length, occurrence, biological function, and the mode of membrane attachment. Poly/oligoSia can be anchored to a membrane via a phospholipid (polySia in bacteria), a glycosphingolipid (oligoSia in gangliosides), an integral membrane glycoprotein, or a glycoprotein attached to a membrane via glycosylphosphatidylinositol. In eukaryotic cells, the attachment of a poly/oligoSia chain to the membrane anchor is usually throu…