Biochemistry: Concepts and Connections
1st Edition
ISBN: 9780321839923
Author: Dean R. Appling, Spencer J. Anthony-Cahill, Christopher K. Mathews
Publisher: PEARSON
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Chapter 6, Problem 7P
a. Based on a more conservative answer to Problem 6 (2.7 x 1092 conformations), estimate the conformational entropy change on folding a mole of this protein into a native structure with only one conformation. (Hint Consider Equation )
b. If the protein folds entirely into a helix with H bonds as the only source of enthalpy of stabilization, and each mole of H bonds contributes -5 kJ/mol to the enthalpy, estimate
c. From your answers (a) and (b), estimate
6. Consider a small protein containing 101 amino acid residues. The protein backbone win have 200 bonds about which rotation can occur. Assume that three orientations are possible about each these bonds.
a. Based on these assumptions, about how many random-con conformations will be possible for this protein?
b. The estimate obtained in (a) is surety too large. Give one reason why.
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Students have asked these similar questions
Protein concentration can readily be determined using the Beer-Lambert law:
A = e l c
where A = absorbance
e = molar absorption coefficient (M-1cm-1)
l = light path length (cm)
c = concentration (M)
If the molar absorption coefficient at 280 nm for yeast ADH is 48860 M-1cm-1 and a 10 mL solution of the protein has an absorbance at 280 nm of 0.4 (as measured by a spectrometer with pathlength 1 cm), then what is the concentration of the protein solution (in μM)? i.e.
concentration = ______ μM
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concentration = _______ mg/mL
For each part of the question, show your calculations to arrive at your answers.
The 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 B
The extinction coefficient or absorptivity (ɛ) of protein A at 340 nm is 6440 M-1 cm-1,
whereas protein B does not absorb at 340 nm. What absorbance will be observed when
light at 340 nm passes through a 5 mm cuvette containing 10 µM of protein A and 10
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Beer-Lambert-law; A = ɛ x C x1; A = absorbance, C= concentration, 1= pathlength).
Chapter 6 Solutions
Biochemistry: Concepts and Connections
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 - Prob. 16PCh. 6 - Do you expect a Pro Gly mutation in a...Ch. 6 - Rank the following in terms of predicted rates...
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- The major difference between a protein molecule in its native state and inits denatured state lies in the number of conformations available. To a firstapproximation, the native, folded state can be thought to have one conformation. The unfolded state can be estimated to have three possible orientations about each bond between residues.(a) For a protein of 100 residues, estimate the entropy change per moleupon denaturation.(b) What must be the enthalpy change accompanying denaturation to allow the protein to be half-denatured at 50 °C?(c) Will the fraction denatured increase or decrease with increasingtemperature?arrow_forwardaffinity of a protein-protein or protein-ligand interaction can be described by the Dissociation Constant, Kd (written below). Consider a protein P and its inhibitor, I. I inhibits P's activity when bound to it: koff _ [A][B] Dissociation Constant: Ka = koN [AB] Question When [I] is 10-7 M, 99% of P's activity is inhibited. What is the Kd of this Protein- Inhibitor interaction?arrow_forwardYou analyze a protein of 100 kDa using SDS-PAGE in the absence and presence of �-mercaptoethanol (BME) and observe the following band pattern in the gels: Which of the following statements about the protein is correct? (the image is attached) a. The protein consists of three polypeptide chains, two of which are connected via S-S bridges. b. The protein consists of two different polypeptide chains connected via S-S bridges. c. The protein has two different folding conformations. d. The protein consists of two different polypeptide chains linked to each other via non-covalent interactions.arrow_forward
- Suppose you have a solution of a protein, which contains a specific Tyr residue that has an actual (measured) pKa of 8.8. The protein binds a ligand by several noncovalent interactions, one of which is a hydrogen bond in which the Tyr phenolic hydroxyl group must serve as a hydrogen bond donor. Calculate the percentage of the protein molecules in which that tyrosyl residue's phenolic hydroxyl group could serve as a hydrogen bond donor at pH 8.5arrow_forwardAmino acid structure For any ionizable group, indicate the pka value and draw the structure that would be expected at the pH inside the cell (~7.4).arrow_forward. A protein gives, under conditions of buffer composition, pH, and tem- perature that are close to physiological conditions, a molecular weight by sedimentation equilibrium measurements of 140,000 g/mol. When the same protein is studied by SDS gel electrophoresis in the absence or presence of the reducing agent B-mercaptoethanol (BME), the pat- terns seen, respectively, in lanes A and B are observed. Lane C contains standards of molecular weight indicated. From these data, describe the native protein, in terms of the kinds of subunits present, the stoi- chiometry of subunits, and the kinds of bonding (covalent, noncova- lent) existing between subunits. / A B - BME + BME STD Serum albumin, 67,000 Ovalbumin, 43,000 Carbonic anhydrase, 30,000 Trypsin inhibitor, 20,000 10 2. 4. Co cm migratedarrow_forward
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