A) illustrate in molecular detail how hemoglobin's reduced oxygen affinity is caused by protonation of thehistidine side chain.b) what is the pKa of the histidine side-chain ionizable group expected to have?|

Introduction: Hemoglobin is the major protein responsible for transporting oxygen from the lungs to…

Answered: A) llustrate in molecular detail how…

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

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You have discovered a new hemoglobin variant you are calling Hb-21. You have noticed the following from your studies of Hb-21: - The binding constant of Hb-21 is the same at pH 7.1 and 7.4.- The binding constant curves generated by Hb-21 and O2 are sigmoidal.- The Hill coefficient for Hb-21 is 3.-The binding constant for Hb-21 with O2 in the presence of 5mM 2,3-bisphosphglycerate is about 6-times lower instead of the 8-times lower that is observed under these conditions for the wild type enzyme. Use this information to answer questions: Based on this information which of these features of hemoglobin would you conclude are altered in Hb-21 as compared to the wild type hemoglobin? ____ the cooperativity.____ the amount of T versus R state in the tissues. ____ the Bohr effect. What is the major issue for an individual with the Hb-21 variant? Explain exactly what aspect of hemoglobin’s function is altered.
A mutation of Lysine 82 (in the DPG-binding pocket) to Arginine in beta sub-unit will most likely result in a) Not enough information b) Normal binding to oxygen c) Higher than normal binding affinity to oxygen d) Lower than normal binding affinity to oxygen
After staining an SDS-PAGE gel with Coomassie Blue G-250, the protein bands are visualized by de-staining the gel in a Coomassie Blue G-250 de-staining solution. This solution is made up of 10% acetic acid, 50% methanol, and 40% distilled water. How much of each of these components do you need to prepare 5 liters of Coomassie Blue G-250 de-staining solution?
Consider a short peptide with the sequence M-C-Q-L-Y-P-E-D-K. List the ionizable groups in this peptide, and the net charge of the whole peptide at pH a) 1.5, b) 7.0, and c)12.0.
Which of the following is true A) The disulfide bridges formed by reduction of the sulfhydryl groups on cysteine destabilizes protein tertiary structure. B) The disulfide bridges formed by oxidation of the sulfhydryl groups on cysteine destabilizes protein tertiary structure. C) The disulfide bridges formed by oxidation of the sulfhydryl groups on cysteine stabilizes protein tertiary structure. D) The disulfide bridges formed by reduction of the sulfhydryl groups on cysteine stabilizes protein tertiary structure.
Use the following information to answer the following questions."The native structure of hemoglobin (HB) comprises of two α and two β subunits, each of which carries a heme group. There appear to be no previous studies that report the in-vitro folding and assembly of Hb from highly unfolded α and β globin in a 'one-pot' reaction. One difficulty that has to be overcome for studies of this kind is the tendency of Hb to aggregate during refolding. This work demonstrates that denaturation of Hb in 40% acetonitrile at pH 10.0 is reversible." (J Am Soc Mass Spectrum 2007, 18, 8-16)Which of the following statements about hemoglobin is most consistent with the information in the passage? Group of answer choices A. a tertiary protein with two polypeptides B. a quaternary protein with two polypeptides C. a tertiary protein with four polypeptides D. a quaternary protein with four polypeptides When nucleotides polymerize to form a nucleic acid, ________. Group of answer choices A. a…
In a molecular disease of hemoglobin, Hemoglobin Rainier, Tyr 145β is replaced by Cys, which forms a disulfide bond with another Cysresidue in the same subunit. This prevents the formation of ion pairs that normally stabilize the T state. How does hemoglobin Rainier differ from normal hemoglobin with respect to the Hillcoefficient? Explain your answers.
Proline is one of the amino acids in the "special" groups of sidechains. One reason for this is the dramatic impact it can have on secondary structure. a) draw the lewis structure for a tripeptide with the sequence Ala-Pro-Ala b) Proline residues are rarely found in alpha helices - in fact, they are often referred to as helix-disrupting amino acids. Thinking about intermolecular interactions, provide an explanation for why proline might disrupt alpha-helices. c) Proline also has a similar effect on beta-sheets, and is rarely found in the middle of beta sheets. Thinking about noncovalent interactions, provide an explanation for why proline might disrupt beta-sheets.
Amino acid substitutions at the interfaces of the a and B subunits of hemoglobin can change the relative stability of the oxy (R) and deoxy (T) forms of the molecule. In one mutant hemoglobin molecule a hydrogen bond involved in stabilizing the R form of the molecule is lost. As a result, would expect this mutant hemoglobin to have a higher or lower affinity for oxygen as a ligand. Explain.
The peptide cys-leu-glu-ala-cys-lys is at pH 7 in oxidizing conditions. Part a) Draw the peptide's titration curve. Part b) What would the pI of the peptide be around?
Below is a list of hypothetical Hemoglobin variants. Circle the name of the variant that is most likely to show an increase in BPG binding. Does such a hypothetical variant cause an increase or decrease in hemoglobin's affinity for oxygen? A. Hb Miami: Leu is substituted with Pro in an alpha helix B. Hb California: Val is substituted with Lys at pH 7.0 C. Hb New york: Tyr is substituted with Met, which disrupts the hydrogen bonding at the a131 interface. D All of the above
The T state of hemoglobin is converted to the R state by what event? Select one: The binding of oxygen destabilizes a more planar heme ring which alters the position of the proximal histidine and subsequently, residues between the alß2 interface. а. b. None of these. The binding of oxygen stabilizes a more planar heme ring which alters the position of the proximal proline and subsequently, residues between the alß2 interface. С. d. The binding of oxygen stabilizes a more planar heme ring which alters the position of the proximal histidine and subsequently, residues between the alß2 interface. The binding of oxygen destabilizes a more planar heme ring which alters the position of the proximal proline and subsequently, residues between the alß2 interface. е.

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A) llustrate in molecular detail how hemoglobin's reduced oxygen affinity is caused by protonation of the histidine side chain. b) what is the pKa of the histidine side-chain ionizable group expected to have?