Biochemistry: Concepts and Connections (2nd Edition)
2nd Edition
ISBN: 9780134641621
Author: Dean R. Appling, Spencer J. Anthony-Cahill, Christopher K. Mathews
Publisher: PEARSON
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Textbook Question
Chapter 6, Problem 10P
Under physiological conditions, the protein hemerythrin exists as an octamer of eight chains of the kind shown in Problem 3.
a. Name two symmetries possible for this molecule
b. Which do you think is more likely? Explain.
c. For the more likely symmetry, what kinds of interactions (isologous, heterologous, or both) would you expect? Why?
3. A schematic structure of the subunit of hemerythrin (an oxygen-binding protein from invertebrate animals) is shown to the right.
a. It has been found that in some of the a-helical regions of hemerythrin, about every third or fourth amino acid residue is a hydrophobic one. Suggest a structural reason for this finding.
b. What would be the effect of a mutation that placed a proline residue at point A in the structure?
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With reference to table 1, discuss the structure activity relationships related to the nature of the substituent R1 and linker group L. In your answer, aim not just to identify trends, but to give possible explanations to them. Include as much detail as possible.
A protein has molecular mass of 200 kDa when measured by gel filtration. When subjected to SDS PAGE with and without 2-mercaptoethanol (2-ME) the gel shown below was obtained.
What is the likely subunit composition of this protein and why?
a. The protein has 4 subunits, with molecular masses 100, 50, 25, and 25 kDa. 25 kDa subunits are linked to each other via noncovalent interactions.
b. The protein has 4 subunits, with molecular masses 100, 50, 25, and 25 kDa. 50 kDa subunit is linked to the one 25 kDa subunit via noncovalent interactions.
c. The protein has 3 subunits, with molecular masses 100, 75 and 25 kDa that are linked by noncovalent interactions.
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e. The protein has 4 subunits, with molecular masses 100, 50, 25, and 25 kDa. 50 kDa subunit is linked to the one 25 kDa subunit by disulfide bonds.
3) You are working on a protein with the following sequence in an area of interest. -Asp-Leu-Leu-Gln-Glu-Glu-Asp-Glu-Ser-Arg a. The current structure, solved at pH 7.4, of this segment has an alpha helix that is disrupted a er the Gln. Why might the alpha helix stop at this residue? b. This protein is involved in Lysosomes in vivo. The secondary structure of this region is expected to change into a complete alpha helix. Why might this change into a complete helix? ( Hint: Lysosomes are acidic!)
Chapter 6 Solutions
Biochemistry: Concepts and Connections (2nd Edition)
Ch. 6 - Prob. 1PCh. 6 - Bovine pancreatic trypsin inhibitor (BPTI; Figure...Ch. 6 - A schematic structure of the subunit of...Ch. 6 - In the protein adenylate kinase, the C-terminal...Ch. 6 - Give two reasons to explain why a proline residue...Ch. 6 - Consider a small protein containing 101 amino acid...Ch. 6 - a. Based on a more conservative answer to Problem...Ch. 6 - The following sequence is part of a globular...Ch. 6 - a. A protein is found to be a tetramer of...Ch. 6 - Under physiological conditions, the protein...
Ch. 6 - Theoretical and experimental measurements show...Ch. 6 - The peptide hormone vasopressin is used in the...Ch. 6 - A protein gives under conditions of buffer...Ch. 6 - A protein gives a single band on SDS get...Ch. 6 - It has been postulated that the normal...Ch. 6 - Below are shown two views of the backbone...Ch. 6 - Do you expect a Pro Gly mutation in a...Ch. 6 - Rank the following in terms of predicted rates...Ch. 6 - Shown below are two cartoon views of the small...Ch. 6 - Prob. 20PCh. 6 - In most cases, mutations in the core of protein...Ch. 6 - A Leu Ala mutation at a site buried the core of...Ch. 6 - Disulfide bonds have been shown to stabilize...Ch. 6 - Cartoon renderings of the proteins Top 7 and adaH2...
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- Three peptides were obtained from a trypsin digestion of two different polypeptides. indicate the possible sequences from the given data and tell what further experiment should be carried out in order to determine the primary structure of the polypeptide. Polypeptide II: 1. Val-Leu-Gly-Glu 2. Ala-Glu-Pro-Arg 3. Ala-Met-Gly-Lysarrow_forwardWhen protein X is subjected to dimethylsuberimidate and SDS electrophoresis a 50 kDa band is seen; when the protein X is subjected to SDS electrophoresis without DMS, two bands of 20 kDa and 10 kDa are seen. How many different oligomeric structures of the native protein X are possible, being consistent with these observed results? one two three none of the above which is the answrr? and explainarrow_forwardThe dissociation constant, Kd for a complex between protein A and protein B is 4.1 μM. If the two proteins are mixed together at initial concentrations of [A]= 0.025 μM and [B] = 4.7 μM, calculate (a) the equilibrium concentrations of A, B, and AB (the dimer formed by A and B) (b) the percentage of A bound to Barrow_forward
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