1. 1 SURVEY OF BIOCHEMISTRY Protein Function

2. 2 PRS In a protein, the most conformationally restricted amino acid is_____ and the least conformationally restricted amino acid is ________. 1. Trp, Gly 2. Met, Cys 3. Pro, Gly 4. Ile, Ala

3. 3 PRS In a protein, the most conformationally restricted amino acid is_____ and the least conformationally restricted amino acid is ________. 1. Trp, Gly 2. Met, Cys 3. Pro, Gly 4. Ile, Ala

4. 4 PRS The arrangement of the regular structural elements and the positions of atoms in the protein are considered part of the ______. 1. Primary structure 2. Secondary structure 3. Tertiary structure 4. Quaternary structure

5. 5 PRS The arrangement of the regular structural elements and the positions of atoms in the protein are considered part of the ______. 1. Primary structure 2. Secondary structure 3. Tertiary structure 4. Quaternary structure

6. 6 PRS Lysine can form a salt bridge by associating with a nearby ____ residue. 1. Pro 2. Ser 3. Gln 4. Glu

7. 7 PRS Lysine can form a salt bridge by associating with a nearby ____ residue. 1. Pro 2. Ser 3. Gln 4. Glu

8. 8 PRS Noncovalent forces that stabilize protein structure include all of the following except _______. 1. The hydrophobic effect 2. Salt bridges 3. Disulfide bridges 4. Metal-ion coordination

9. 9 PRS Noncovalent forces that stabilize protein structure include all of the following except _______. 1. The hydrophobic effect 2. Salt bridges 3. Disulfide bridges 4. Metal-ion coordination

10. 10 PRS Which of the following DNA sequences is (are) palindromic? 1. AGCT 2. AAGNCTT 3. AGGA 4. #1 and #2

11. 11 PRS Which of the following DNA sequences is (are) palindromic? 1. AGCT 2. AAGNCTT 3. AGGA 4. #1 and #2 5’-AGCT-3’ 3’-TCGA-5’ 5’-AAGNCTT-3’ 3’-TTCNGAA-5’ 5’-AGGA-3’ 3’-TCCT-5’

12. 12 Protein Function: Overview Transport Contraction Protection Catalysis Regulation –Gene regulation –Hormonal regulation Structural Support Chapter 7 - with emphasis on Myoglobin and Hemoglobin

13. 13 Why focus on Mb and Hb? Biological Importance

14. 14 Why focus on Mb and Hb?

15. 15 Why focus on Mb and Hb? Biological Importance Role in Transport of O 2 –Myoglobin: O 2 transport to muscles –Hemoglobin: O 2 transport from lungs Ligand Binding –Simple binding –Cooperativity and Allosteric Interactions

16. 16 Ligand Binding: General Concepts How can ligand binding be: –Described? –Measured? –Regulated? Distinctions between binding categories –One Protein + One Ligand –One Protein + Multiple Ligands

17. 17 Heme is what O 2 binds Heme is a porphyrin prosthetic molecule

18. 18 Myoglobin and Hemoglobin MyoglobinHemoglobin 1 4 8 8 Mb - O 2 Hb - O 2 # subunits # heme groups # Alpha Helices 18% identical residues

19. 19 Structure Changes on Binding Fig 6-38 shows Mb “breathing” How is O 2 binding to Mb described? Show on board…

20. 20 O 2 Binding to Myoglobin Shape indicates simple binding of O 2 to Mb

21. 21 Hb has 2 conformations Without O 2 T State With O 2 R State

22. 22 O 2 Binding to Hemoglobin Arteries carry oxygenated blood Veins carry deoxygenated blood

23. 23 Upcoming… More on Hb and Mb on Friday General concepts –Muscle Contraction –Antibodies Exam #1 on Thursday –Boggs B6A 4-5 pm