2. (a)The binding site of 2,3-bisphosphoglycerate (BPG) (red stick figure) in the deoxyhemo-globin molecule is illustrated below. Note that the two phosphate groups and the carboxylate group ofthe BPG molecule confer strong, negative electrostatic character to the molecule.B₁-subunit1.2.3.5.6.B₁(b)Mutant HemoglobinHb RaleighHb HelsinkiThe mutant hemoglobins listed below each have a mutant amino acid in the ß-subunit directly in or inthe vicinity of the BPG binding site. Rank the affinity of the following mutant hemoglobins for bindingBPG (red stick figure above).. Explain your reasoning. The notation, for instance, as given for HbRaleigh Val(31)Ala means that Val-1, the first amino acid residue of the ß-subunit, has been substitutedby Ala.Hb RahereHb Rancho MirageHb Little RockB₂Hb OhioMutationVal (31)AlaLys(382) MetLys(382)) ThrHis(143)AspHis(3143)Glna-NHẠAla(142)AspHis 2His 143BPGHis 143Lys 82His 2Rank the affinity of the mutant hemoglobins for binding BPG.a-NH,*B2-subunitExplanation of effect of mutation on BPGbinding

To comprehend the BPG binding site within hemoglobin, it's important to note that it resides within…

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Human Physiology: From Cells to Systems (MindTap Course List)

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter11: The Blood

Section: Chapter Questions

Problem 1SQE

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What qualitative effect would you expect each of the following to have on the Pgp of hemoglobin? (a) Increase in pH from 7.2 to 7.4 (b) Increase in Pco, from 20 to 40 mm Hg (c) Dissociation into monomer polypeptide chains
What qualitative effect would you expect each of the following to have onthe P50 of hemoglobin?(a) Increase in pH from 7.2 to 7.4(b) Increase in PCO2 from 20 to 40 mm Hg(c) Dissociation into monomer polypeptide chains(d) Decrease in 2,3-BPG concentration from 7 mM to 5 mM in red cells.
2B. S. aureus hemolysin B attacks the RBC cell membrane by hydrolyzing the sphingomyelin headgroup: ОН HN .R hemolysin B cuts this bond i) Draw a plausible mechanism of hydrolysis for this lipid headgroup. Let B- and BH be general base and general acid. 00-P-O LOR2 OR, ii) Why is this damaging to the overall membrane architecture of the RBC?
The 2-3 phosphoglycerate (BFG) binds to the central gap formed by the hemoglobin monomers (a2b2) facilitating the reversible release of oxygen. Approximate relationships between BFG concentrations in red blood cells and Pos in hemoglobin are in the table.a) Draw the reaction schemeb) Write the forces that condition the union between hemoglobin and BFG
Please fill in the following blanks with the options that correctly finishes the sentence. a. At a low O₂ pressure the [Select] hemoglobin is in a [Select] [Select] [Select] 9 [Select] " bond with [Select] heme, and the protein's central channel is [Select] b. The proximal histidine forms a(n) [Select] state is stabilized. In this conformation state, the heme prosthetic groups is each subunit's heme is more likely to be the proximal histidine is [Select ] bond with while the distal histidine forms a(n) [Select] to the
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.
Apohemoglobin (apoHb) is a dimeric globular protein with two vacant heme‐binding. The preparationof apoHb is based on partial hemoglobin (Hb) unfolding to facilitate heme extraction into an organic solvent. What is an appropriate method for removing the heme? a. An acidic buffer to protonate the His axial ligand in the presence of ureaas the denaturing agent. b. An acidic buffer to protonate the His axial ligand in the presence of mercatoethanol as the denaturing agent. c. A basic buffer to deprotonate the His axial ligand in the presence of ureaas the denaturing agent. d. An basic buffer to protonate the His axial ligand in the presence of mercatoethanol as the denaturing agent.
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.
Hemoglobin from different species can have different numbers of subunits. Let's consider three hemoglobin molecules: n = 1, n = 4, and n = 8, where each subunit has an oxygen P50 = 30 torr. (Recall that Pso is essentially a Kp and that oxygen partial pressure (torr) is directly proportional to concentration.) Which molecule transports the most O2 between the lungs (pO2 = 100 torr) and peripheral tissues (pO2 = 30 torr)? Please justify your answer.
2,3-Bisphosphoglycerate lies in a central cavity within the hemoglobin tetramer, stabilizing the T state. What would be the effect of mutations that placed the BPG-binding site on the surface of hemoglobin?
Bisphosphoglycerate lies in a central cavity within the hemoglobin tetramer, stabilizing the T state. What would be the effect of mutations that placed the BPG-binding site on the surface of hemoglobin?
How does the difference between the-chain and the -chain of hemoglobin explain the differences inoxygen binding between Hb A and Hb F?

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