A Leu →Ala mutation at a site buried in the core of the enzyme lysozymeis found to be destabilizing. Explain the observed effect of this mutationon lysozyme stability by predicting how enthalpy (ΔH°), conformationalentropy (ΔS°peptide), and the hydrophobic effect (ΔS°solvent) are expected to change for the mutant compared to wild-type lysozyme. Explain how ΔG°for unfolding is affected by your predicted changes in enthalpy or entropy.

A Leu →Ala mutation at a site buried in the core of the enzyme lysozymeis found to be destabilizing. Explain the observed effect of this mutationon lysozyme stability by predicting how enthalpy (ΔH°), conformationalentropy (ΔS°peptide), and the hydrophobic effect (ΔS°solvent) are expected to change for the mutant compared to wild-type lysozyme. Explain how ΔG°for unfolding is affected by your predicted changes in enthalpy or entropy.

Name: A Leu →Ala mutation at a site buried in the core of the enzyme lysozym
Uploaded: 2024-03-20T06:42:41.000Z
Channel: Bartleby
Description: A Leu →Ala mutation at a site buried in the core of the enzyme lysozymeis found to be destabilizing. Explain the observed effect of this mutationon lysozyme stability by predicting how enthalpy (ΔH°), conformationalentropy (ΔS°peptide), and the hydro

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter26: Synthesis And Degradation Of Nucleotides

Section: Chapter Questions

Problem 6P: Allosteric Regulation of Ribonucleotide Reductase by ATP and Deoxynucleotides Describe the...

See similar textbooks

Similar questions

b. Compounds A, B, C, and D are known to be intermediates in the pathway for production of protein E. To determine where the block in protein-E production occurred in each individual, the various intermediates were given to each individuals cel Is in culture. After a few weeks of growth with the intermediate, the cells were assayed for the production of protein E. The results for each individuals cells are given in the following table. A plus sign means that protein E was produced after the cells were given the intermediate listed at the top of the column. A minus sign means that the cells still could not produce protein E even after being exposed to the intermediate at the top of the column. Denote the point in the pathway in which each individual is blocked.
a. Compounds A, B, C, and D are known to be intermediates in the pathway for production of protein E. To determine where the block in protein-E production occurred in each individual, the various intermediates were given to each individuals cel Is in culture. After a few weeks of growth with the intermediate, the cells were assayed for the production of protein E. The results for each individuals cells are given in the following table. A plus sign means that protein E was produced after the cells were given the intermediate listed at the top of the column. A minus sign means that the cells still could not produce protein E even after being exposed to the intermediate at the top of the column. Draw the pathway leading to the production of protein E.
Allosteric Regulation of Ribonucleotide Reductase by ATP and Deoxynucleotides Describe the underlying rationale for the regulatory effects exerted on ribonucleotide reductase by ATP, dATP, dTTP, and dGTP.
The Energy Cost of dTTP Synthesis (Integrates with Chapter 20.) Starting from HCO3, glutamine, aspartate, and ribosc-5-P, how many ATP equivalents are consumed in the synthesis of dTTP in a eukaryotic cell, assuming dihydroorotate oxidation is coupled to oxidative phosphorylation? How does this result compare with the ATP costs of purine nucleotide biosynthesis calculated in problem 2?
Lysozyme is an enzyme that hydrolyzes bacterial cell wall polysaccharides. When this reaction is carried out in the presence of H218O, it is observed that there is retention of configuration at the C1 carbon of the D site sugar as shown below: Would this result suggest that the enzyme mechanism involves the direct nucleophilic attack of water at C1 or that the enzyme mechanism involves attack by a nucleophilic amino acid side chain of the enzyme that generates a transient covalent intermediate?
The distal Histidine (His 64) in myoglobin is subjected to three different mutations, this is one of them: H64N. (Histidine to Aparagine) For the mutation, draw a theoretical binding curve and CO relative to the O2 and CO binding curves for wild-type Mb (see example below). Provide a clear rationale for the binding curve.
The first 32 amino acids from the N terminus of the protein bovine angiogenin were determined by Edman degradation and have the sequence:AQDDYRYIHFLTQHYDAKPKGRNDEYCFNMMK(a) Identify the sites of cleavage during trypsin-catalyzed hydrolysis of this protein.(b) What are the cleavage sites using chymotrypsin?
Lysozyme is an enzyme that hydrolyzes bacterial cell wall polysaccharides. When this reaction is carried out in the presence of H218O, it is observed that there is retention of configuration at the C1 carbon of the D site sugar as shown below Two key amino acid side chains (an Asp and a Glu) essential for lysozyme’s catalytic activity are positioned above and below the C1-O bond that is cleaved as shown below. Suggest a plausible mechanism for the reaction that starts with a nucleophilic attack at C1.
Using the quarternary structure of hemoglobin shown inFigure 9-3(d), explain in structural terms how a mutation in the β subunit protein could be suppressed by amutation in the a subunit gene.
The cDNA sequence for a secreted protein shows that it contains two Asn-X-Ser/Thr motifs but nothing is known about the glycosylation of the protein. If you consider that either or both of these sites could be glycosylated and the oligosaccharides processed to either a Man5 high mannose structure or to a sialylated complex bi-antennary structure, how many possible glycoforms of the protein would there be? Explain why it is likely that such a protein would actually have very many more glycoforms.
Mutants of Neurospora crassa that lack carbamoyl phosphate synthetase I (CPS I) require arginine in the medium in order to grow, whereas mutants that lack carbamoyl-phosphate synthetase II (CPS II) require a pyrimidine, such as uracil. A priori, one would expect the active CPS II in the arginine mutants to provide sufficient carbamoyl phosphate for arginine synthesis, and the active CPS I in the pyrimidine mutants to “feed” the pyrimidine pathway. Explain these observations.
The proximal histidine residues have been replaced by glycine residues by mutation of the cloned genes for both the α and β subunits of hemoglobin. With the tetrameric mutant hemoglobin (all subunits being mutant, α H F8 G, β H F8 G), it was found that the “proximal” coordination bonds to hemes in the mutant protein could be replaced by having the small molecule imidazole in the buffers. Oxygen binding curves for the tetrameric mutant hemoglobin were measured. A. The degree of cooperativity in oxygen binding for the mutant hemoglobin (with imidazole present) would be expected to 1) increase 2) decrease 3) not be affected) compared with the normal protein. B. Justify your answer to part A in terms of what you know about the structural basis of cooperativity in hemoglobin. C. How would the Hill coefficient for the mutant be expected to change compared with nH for normal hemoglobin, which is ~3?