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Proteomics. BIOL 4900. Section 1 – Amino Acid Structure. Formation of Peptide bond. H 2 O. Section 2 – Polypeptide Diversity. Insulin primary structure. Primary Structure – linear sequence of amino acids in a polypeptide chain. 20 100 = 1.27 x 10 130 possible combinations
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Proteomics BIOL 4900
Section 2 – Polypeptide Diversity Insulin primary structure Primary Structure – linear sequence of amino acids in a polypeptide chain 20100 = 1.27 x 10130 possible combinations 9 x 1078 atoms estimated in universe
Section 3 – Secondary Structure Resonance prevents bond rotation of peptide bond
Pitch = 5.4 Å Turn = 3.4 aa C=O forms H bond With N-H of n+4 residue
Salt Bridges Metal Ions
Sialic acids are important for glycoproteins and glycolipids; recognition site of Influenza Viruses
Sugar derivatives Should be able to draw
Glycoproteins Carbohydrates can account for up to 70% of a protein by mass Half of all mammalian proteins are glycosylated
Biological Activity • Define protein structure • Usually on surface • limit conformation; stabilize fold • Recognition • Glycoconjugates • Lectins – identify specific oligosaccharides • Selectins – attachment of leukocytes • Blood groups
Section 9 – Lipid Classification • Functions of lipids • essential component of biological membranes • Hydrocarbon chains serve as energy • intra- and intercellular signaling
unsaturated saturated polysaturated even number of carbons 18:0 18:1cΔ9 18:2cΔ9, 12 18:2cΔ9, 12, 15 Δ9 double bond almost always cis ω-3 fatty acid
Lipid anchors for proteins • prenylated • fatty acylated • glycosylphatidylinositol
Prenylation Occurs at CXXY If Y = Ala, Met, Ser; farnesylated If Y = Leu; Geranylgeranylated
Fatty acylated • Can add myristic acid or palmitic acid • Myristoylation is very stable • amide linkage between α-amino of N-terminal G and myristic acid • Palmiyolation can be undone by palmitoyl thioesterases • involved in protein signaling