amylose Amylopectin or glycogen Polysaccharides Glycogen and Amylopectin

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amylose

amylose

Amylopectin or glycogen

Amylopectin or glycogen

Polysaccharides Glycogen and Amylopectin Structures Glycogen and Amylopectin are a(1 -4) chains with a(1

Polysaccharides Glycogen and Amylopectin Structures Glycogen and Amylopectin are a(1 -4) chains with a(1 -6) branches Amylopectin Glycogen

cellulose

cellulose

cellulose

cellulose

Carbohydrates – Complex (Polysaccharides) Cellulose fibers Cellulose = polysaccharide found in plant cell walls

Carbohydrates – Complex (Polysaccharides) Cellulose fibers Cellulose = polysaccharide found in plant cell walls Macrofibril Microfibril Chains of cellulose

chitin N-acetyl-D-glucosamine units in (b-->4) linkage

chitin N-acetyl-D-glucosamine units in (b-->4) linkage

Glycoprotein • Glycoproteins are proteins that contain oligosaccharide chains (glycans) covalently attached to their

Glycoprotein • Glycoproteins are proteins that contain oligosaccharide chains (glycans) covalently attached to their polypeptide side-chains. • The process of attaching the glycans is known as glycosalation. • The sugar groups attached to glycoprotein can assist in protein folding or improve a proteins’ stability.

Functions of Glycoproteins Function Glycoprotein Structural Molecule Collagen Lubricant and Protective Agent Mucins Transport

Functions of Glycoproteins Function Glycoprotein Structural Molecule Collagen Lubricant and Protective Agent Mucins Transport Molecule Transferrin, ceruloplasmin Immunologic Molecule Immunoglobins, histocompatibility antigens Enzyme Various, e. g alkaline phosphatase Cell Attachment-recognition site Proteins involved in cell to cellc ommunication Interact with specific carbohydrates Lectins, selectins (cell adhesion lectins), antibodies

Functions of Glycoproteins Function Glycoprotein Receptor Various Proteins in hormone and drug action Affect

Functions of Glycoproteins Function Glycoprotein Receptor Various Proteins in hormone and drug action Affect folding of certain proteins Calnexin, Calreticulin Regulation of development Notch and its analogs, key proteins in development Hemostasis (and thrombosis) Specific glycoproteins on the surface membranes of platelets

glycosaminoglycans of extracellular matrix lubricants in the synovial fluid of joints cartilage, tendons, ligaments

glycosaminoglycans of extracellular matrix lubricants in the synovial fluid of joints cartilage, tendons, ligaments a variety of horny structures formed of dead cells: horn, hair, hoofs, nails

Proteoglycans: cell surface or extracellular matrix A typical tetrasaccharide linker (blue) connects a glycosamino-glycan—in

Proteoglycans: cell surface or extracellular matrix A typical tetrasaccharide linker (blue) connects a glycosamino-glycan—in this case chondroitin 4 -sulfate (orange)—to a Ser residue (pink) in the core protein. The xylose residue at the reducing end of the linker is joined by its anomeric carbon to the hydroxyl of the Ser residue.

Proteoglycan aggregate of the extracellular matrix One very long molecule of hyaluronan is associated

Proteoglycan aggregate of the extracellular matrix One very long molecule of hyaluronan is associated noncovalently with about 100 molecules of the core protein aggrecan

Interactions between cells and the extracellular matrix with binding sites for both integrin and

Interactions between cells and the extracellular matrix with binding sites for both integrin and the proteoglycan

linkages in glycoproteins Ser/thr

linkages in glycoproteins Ser/thr

Bacterial lipopolysaccharides

Bacterial lipopolysaccharides

Lectins, found in all organisms, are proteins that bind carbohydrates with high specificity cell-cell

Lectins, found in all organisms, are proteins that bind carbohydrates with high specificity cell-cell recognition, signaling, adhesion processes, intracellular targeting, deterrent to insects

lectin-ligand interactions in lymphocyte movement to the site of an infection Stronger interaction near

lectin-ligand interactions in lymphocyte movement to the site of an infection Stronger interaction near the site of inflammation

Helicobacter pylori Interaction between a bacterial surface lectin and an oligosaccharide of the gastric

Helicobacter pylori Interaction between a bacterial surface lectin and an oligosaccharide of the gastric epithelium

Recognition and adhesion at the cell surface

Recognition and adhesion at the cell surface