1 SURVEY OF BIOCHEMISTRY Protein Function
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 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 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 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 PRS Lysine can form a salt bridge by associating with a nearby ____ residue. 1. Pro 2. Ser 3. Gln 4. Glu
7 PRS Lysine can form a salt bridge by associating with a nearby ____ residue. 1. Pro 2. Ser 3. Gln 4. Glu
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 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 PRS Which of the following DNA sequences is (are) palindromic? 1. AGCT 2. AAGNCTT 3. AGGA 4. #1 and #2
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 Protein Function: Overview Transport Contraction Protection Catalysis Regulation –Gene regulation –Hormonal regulation Structural Support Chapter 7 - with emphasis on Myoglobin and Hemoglobin
13 Why focus on Mb and Hb? Biological Importance
14 Why focus on Mb and Hb?
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 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 Heme is what O 2 binds Heme is a porphyrin prosthetic molecule
18 Myoglobin and Hemoglobin MyoglobinHemoglobin Mb - O 2 Hb - O 2 # subunits # heme groups # Alpha Helices 18% identical residues
19 Structure Changes on Binding Fig 6-38 shows Mb “breathing” How is O 2 binding to Mb described? Show on board…
20 O 2 Binding to Myoglobin Shape indicates simple binding of O 2 to Mb
21 Hb has 2 conformations Without O 2 T State With O 2 R State
22 O 2 Binding to Hemoglobin Arteries carry oxygenated blood Veins carry deoxygenated blood
23 Upcoming… More on Hb and Mb on Friday General concepts –Muscle Contraction –Antibodies Exam #1 on Thursday –Boggs B6A 4-5 pm