F BICH 410 1st Edition Lecture 16 Outline of Last Lecture Disaccharides Polysaccharides Outline of Current Lecture Polysaccharides o Pepditoglycan Bacterial cell wall component Made of n acetylmuramic acid NAM and N aceytlglucosamine NAG Gram positive have pentaglycine crosslink while gram negative hace direct crosslink Gram positive have thick cell walls while gram negative hace thinner and are covered by an outer membrane Gram negative are more antibiotic resistant than gram positive Have peptide chain L ala D Glu L Lys D Ala o Antibiotics pencillin binds and inactivates the enzyme that catalyzes the crosslinking of peptidoglycan B lactamase can be secreted by bacteria causing penicillin resistance Vancomycin binds to the D ala D ala sequence in peptide chain inhibiting crosslinking o Glycoproteins membrane associated and secreted proteins of Eukarya typically are glycosylated Oligosaccharides attached to proteins via N glycosidic or O glucosidic O linked are synthesized in Golgi and are created by serial additions to the monosaccharide Glycosylation occurs at specific 2ary and 3ary structures Ser and Thr are not part of AA seq N linked amide nitrogen of an Asn residue with sequence ASN X SER or ASN XTHR Occurs cotranslationally and are glycosolated then processed to give a common core oligosaccharide Very common for proteins and creates many functions such as protein lifetime and trafficking o Glycolipids and lipopolysaccharides Sialic acid found at termini of most oligosaccharide chains of glycoproteins glycolipids Acts as a ligand for sugar binding proteins ie virus bacteria Cleavage of acid exposes galctose which is required for protein turnover These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o Proteoglycans glucosaminoglycans generally linked to extracellular proteins to form proetoglycans forms connective tissues Cartilage matrix proteoglycan very hydrated so when compressed releases water and when released absorbs water o Protein carbohydrate interaction lectins proteins binding carbs Lectins decipher sugar code and serve as cell cell recognition signaling and for adhesion Selectins allow leukocytes to attach to surface of endothelial cells Lectin oligosaccharide interactions are very specific Lectin receptors recognize enyzmes with mannose 6 phosphate and target for delivery to lysosomes I cell disease when this works defectively C reactive protein prevents inflammation damage Influenze hemagglutin HA HA binds to sialic acid which triggers formation of endosome Ricin biochemical warfare agent Obtained from castor oil plant has lectin that binds galactosyl and enables protein to enter cell and also contains a N glycosidase that causes cleavage of rRNA resulting in cell death Blood and Carb O antigen A antigen B antigen Lipids soluble in organic solvents o Form bilayer for membranes Serve as energy storage through hydrocarbon sidechains Allow for intra and intercellular signaling o Classification fatty acid triacylglycerols glycerophospholipids sphingolipids steroids o Fatty acids carboxylic acids with long hydrocarbon groups typically C16 C18 Saturated pack tightly and are more rigid Unsaturated pack less orderedly and with more motion double bonds have cis configuration 1st double bond typ Between C9C10 Nomenclature C18 1 n 3 18Carbons and 1 double bond on 3rd carbon Omega fatty acids aka N fatty acids C16 1n 3 or C20 5 n 3 Must be able to draw a saturated and unsaturatedfatty acid using zig zag notation showing carboxylic acid and cis bond stearic acid and oleic acid Must be able to draw omega fatty acids stearic acid C18 0 oleic acid c18 1 N9 linoleic acid c18 2 n 9 12 and alpha linolenic acid C18 3 n 9 12 15 o Triacylglycerols Triglycerides Fatty acid triesters of glycerol Glycerol binded to 3 fatty acids Usually contain different types of fatty acid residues Melting temps animal fats have high percent saturation of fatty acids plant fats have high percent of unsaturated melting temp will cary based on degree saturation and chain length Triacylglycerols fxn as energy reservoirs human can survive 2 3 months on fat Also insulate o Olestra carb based fat substitute inhibits absorption of vitamins and nutrients Saponification formation of triacylglycerols in soaps Non polar lipids energy storage Polar bilayers Finish lipids next class with glycerophospholipids sphingolipids and steroids