1. Final Exam – 104A Monday, May 10 8:00 – 11:00 am 100 Noyes AQD,AQE,AQFYuan AQA,AQLSedlacek AQI,AQKSmith 62 Krannert Art Museum AQB,AQCPark AQNGupta AQGPhelan

2. Final Exam – 104C Friday, May 14 7:00 – 10:00 pm 228 Natural History Bldg. CQA,CQCRanderia CQB,CQPPhelan CQI,CQJLoman 100 Noyes CQD,CQE,CQKDokukin CQG,CQKBrea

3. Amino acids R-groupsnon-polar polar acidic basic proteinscondensation between carboxylic acids and amines + + H2OH2O carboxylic acid amine amide

4. Amides amides resonance structure alanine glycine Ala-Gly +H 2 O dipeptide

5. Polypeptides “backbone” N1-N1- C1-C1-C1-C1-N2-N2-C2-C2-C2-C2-N3-N3-C3-C3-C3-C3- peptide bonds _ H _ H = O OH _ H _ H = O = O _ R _ R _ R N-terminal residue C-terminal residue biological activity = structure protein structure 4 levels

6. Primary structure sequence of amino acids hemoglobintransports O 2 and CO 2 4 protein chains 300 amino acids 6th amino acid from N-terminus Glu Val -CH 2 CH 2 -CO 2 H -CH(CH 3 ) 2 R Sickle cell anemia water soluble water insoluble

7. Secondary structure hydrogen bonding backbone groups H-bond donors N1-N1- C1-C1-C1-C1-N2-N2-C2-C2-C2-C2-N3-N3-C3-C3-C3-C3- _ H _ H = O OH _ H _ H = O = O _ R _ R _ R H-bond acceptors Two main secondary structures :  -helix  -sheet

8. Alpha helix Every C=Obonded to N-H4 residues away forms a helix core is backbone R-groups outside 3.6 amino acids per turn proline breaks helix = O C no H-bonding C = O N H

9. Beta sheet Every C=Obonded to N-Hfar apart in 1 o structure on different chains peptide chains extendedside-by-side maximal H-bonding for anti-parallel chains small R-groupsabove and below the sheet if not  -helix or  -sheet random coil

10. Proteins 1 o structureamino acid sequence 2 o structure  - helix  -sheet H-bonding between C=O and N-H of backbone -- ++ some proteins only have 1 o and 2 o structure: fibroin (silk)  -sheet keratin collagen hair skin  - helix insoluble in H 2 O non-polar residues Fibrous

11. Disulfide bonds cysteine-CH 2 -SH S-HH-S CC H N C CC H N C reduced [O][O] SS CC H N C CC H N C oxidized

12. Gly-Glu-His- Ala- Phe-Ser- Val-His-Ile-Met-Arg- Asp- Val-Asn- Tertiary structure Primary structuresequence of amino acids Alanine Non-polar Phenylalanine Polar Serine Valine Acidic or Basic Glutamic acid Histidine Isoleusine Methionine Arginine Asperagine Aspartic acid Glycine Ala-Phe-Ser-Ser-Val-Glu-His-Ile-Met-Arg-Asp-Val-His-Asn-Gly

13. Tertiary structure Ala-Phe-Ser-Ser-Val-Glu-His-Ile-Met-Arg-Asp-Val-His-Asn-Gly arrange these in an  -helix Ala 1 Phe 2 Ser 3 4 Val 5 Glu 6 His 7 Ile 8 Met 9 Arg 10 Asp 11 Val 12 His 13 Asn 14 Gly 15 non-polarpolar interior exterior

14. Tertiary structure interaction of the R-groups - - + - + - - + proteins fold around non-polar groups globular proteins hydrophobic residues inside polar and charged residues outside

15. Tertiary structure 1. Hydrophobic interactions non-polar R-groups LDF 2. Hydrogen bonding between H-bond donors and acceptors polar R-groups 3. Ionic bonds(salt bridges)acidic and basic R-groups 4. Covalent bonds (disulfide)cysteins ion-ion interactions of R-groups

16. CH 3 NH + N-terminus C-terminus Pro AlaPheArgAsp Pro S S Cys His - O-CH O = Fe 2+