Biomaterial Database

The cholesterol-dependent cytolysins pneumolysin and streptolysin O require binding to red blood cell glycans for hemolytic activity. 2014

Lucy K Shewell, and Richard M Harvey, and Melanie A Higgins, and Christopher J Day, and Lauren E Hartley-Tassell, and Austen Y Chen, and Christine M Gillen, and David B A James, and Francis Alonzo, and Victor J Torres, and Mark J Walker, and Adrienne W Paton, and James C Paton, and Michael P Jennings

Institute for Glycomics, Griffith University, Gold Coast, QLD 4222, Australia;

The cholesterol-dependent cytolysin (CDC) pneumolysin (Ply) is a key virulence factor of Streptococcus pneumoniae. Membrane cholesterol is required for the cytolytic activity of this toxin, but it is not clear whether cholesterol is the only cellular receptor. Analysis of Ply binding to a glycan microarray revealed that Ply has lectin activity and binds glycans, including the Lewis histo-blood group antigens. Surface plasmon resonance analysis showed that Ply has the highest affinity for the sialyl LewisX (sLeX) structure, with a K(d) of 1.88 × 10(-5) M. Ply hemolytic activity against human RBCs showed dose-dependent inhibition by sLeX. Flow cytometric analysis and Western blots showed that blocking binding of Ply to the sLeX glycolipid on RBCs prevents deposition of the toxin in the membrane. The lectin domain responsible for sLeX binding is in domain 4 of Ply, which contains candidate carbohydrate-binding sites. Mutagenesis of these predicted carbohydrate-binding residues of Ply resulted in a decrease in hemolytic activity and a reduced affinity for sLeX. This study reveals that this archetypal CDC requires interaction with the sLeX glycolipid cellular receptor as an essential step before membrane insertion. A similar analysis conducted on streptolysin O from Streptococcus pyogenes revealed that this CDC also has glycan-binding properties and that hemolytic activity against RBCs can be blocked with the glycan lacto-N-neotetraose by inhibiting binding to the cell surface. Together, these data support the emerging paradigm shift that pore-forming toxins, including CDCs, have cellular receptors other than cholesterol that define target cell tropism.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009844	Oligosaccharides	Carbohydrates consisting of between two (DISACCHARIDES) and ten MONOSACCHARIDES connected by either an alpha- or beta-glycosidic link. They are found throughout nature in both the free and bound form.	Oligosaccharide
D011134	Polysaccharides	Long chain polymeric CARBOHYDRATES composed of MONOSACCHARIDES linked by glycosidic bonds.	Glycan,Glycans,Polysaccharide
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D002241	Carbohydrates	A class of organic compounds composed of carbon, hydrogen, and oxygen in a ratio of Cn(H2O)n. The largest class of organic compounds, including STARCH; GLYCOGEN; CELLULOSE; POLYSACCHARIDES; and simple MONOSACCHARIDES.	Carbohydrate
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D004912	Erythrocytes	Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.	Blood Cells, Red,Blood Corpuscles, Red,Red Blood Cells,Red Blood Corpuscles,Blood Cell, Red,Blood Corpuscle, Red,Erythrocyte,Red Blood Cell,Red Blood Corpuscle
D005434	Flow Cytometry	Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.	Cytofluorometry, Flow,Cytometry, Flow,Flow Microfluorimetry,Fluorescence-Activated Cell Sorting,Microfluorometry, Flow,Cell Sorting, Fluorescence-Activated,Cell Sortings, Fluorescence-Activated,Cytofluorometries, Flow,Cytometries, Flow,Flow Cytofluorometries,Flow Cytofluorometry,Flow Cytometries,Flow Microfluorometries,Flow Microfluorometry,Fluorescence Activated Cell Sorting,Fluorescence-Activated Cell Sortings,Microfluorimetry, Flow,Microfluorometries, Flow,Sorting, Fluorescence-Activated Cell,Sortings, Fluorescence-Activated Cell
D006017	Glycolipids	Any compound containing one or more monosaccharide residues bound by a glycosidic linkage to a hydrophobic moiety such as an acylglycerol (see GLYCERIDES), a sphingoid, a ceramide (CERAMIDES) (N-acylsphingoid) or a prenyl phosphate. (From IUPAC's webpage)	Glycolipid