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Proteins PowerPoint Presentation

Proteins

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Proteins

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  1. Proteins

  2. Proteins • Polymers composed of amino acids • Protein = Polypeptide (polymer) • Monomer = Amino acids • Peptide bonds • Amino acid • Amine Group (NH2) • Basic • Carboxylic Acid Group (COOH) • Acidic

  3. Protein Functions

  4. 4 Levels of Protein Structure • Primary level • Sequence of amino acids • Polar covalent bonds link the amino acids • Only level that doesn’t use hydrogen bonds • Secondary • Hydrogen bonding between amino acid side groups • The sequence of amino acids converts into 1 of 2 forms • α-helix • β-pleated sheets

  5. 1’ and 2’ Levels Protein Structure

  6. 1’ & 2’ Animations • 05_21aPrimaryStructure.swf • 05_21bSecondaryStructure.swf

  7. 3’ & 4’ Structure • Tertiary • 3D shape of a polypeptide • Many types of bonds/interactions between side groups • Disulfide bridges are most significant here • Quaternary • 2 or more polypeptides (subunits) of a protein • Not found in all proteins • Same bonds/interactions as tertiary level

  8. Tertiary & Quaternary Levels

  9. 3’ & 4’ Animations • 05_21cTertiaryStructure.swf • 05_21dQuaternaryStructure.swf • Animation-03-01.swf

  10. Protein Denaturation

  11. Protein Denaturation • Denaturation • Protein unravels and loses its native conformation • Structure & Function • Change in the protein’s structure = loss of function • Denaturation occurs: • Organic solvent • Any chemical that disrupts the tertiary structure • Heat (excessive)

  12. Chaperonins • Proteins that assist the proper folding of other proteins • Provide stable, insulated environment for polypeptide to achieve the correct conformation

  13. Protein Questions • Name all of the bonds in primary protein structure? • What bonds hold together secondary structure? • What about tertiary level? Quaternary? • Which level of protein structure is NOT found in all proteins?

  14. Protein Questions (Answers) • Name all of the bonds in primary protein structure? • Polar Covalent or peptide • What bonds hold together secondary structure? • Hydrogen bonds, though not really bonds • What about tertiary level? Quaternary? • Hydrogen, Disulfide bridges, Hydrophobic interactions, Ionic bonds, etc. • Which level of protein structure is NOT found in all proteins? Quaternary

  15. Protein Questions (Page 2) • What is the name of a protein’s monomer? • What is the name of a protein’s polymeric form? • What are the 2 functional groups on an Amino Acid?

  16. Protein Questions (Page 2) • What is the name of a protein’s monomer? • Amino Acid • What is the name of a protein’s polymeric form? • Polypeptide • What are the 2 functional groups on an Amino Acid? • Amino – (basic) & Carboxyl – (acidic)