Protein Biotechnology Multiple Questions Assignment
Q1: High salt solution such as (NH4)2SO4 is often used to precipitate proteins from natural materials, such as IgG from animal blood. Explain the science behind this practice.
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Q2: Which of the following peptides will be eluted from a reverse phase column last if a gradient solution starting with 100% H20 and ending with 100% isopropanol is applied to the column? Provide a brief explanation.
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(1) Ala-Thr-Tyr-Asn-lle-Ala-Ser-Cys-Leu-Val-Pro
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(2) Lys-His-Val-Ala-Leu-Met-Phe-Trp-Arg-His-His
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(3) Glu-Arg-Asp-Asp-Gly-Thr-Ser-Glu-Glu-Ser-Gly
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Q3: Which of the following peptides will be eluted from a cation exchange column last?
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1) Ala-Thr-Tyr-Asn-lle-Ala-Ser-Cys-Leu-Val-Pro
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2) Lys-His-Val-Ala-Leu-Met-Phe-Trp-Arg-His-His
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3) Glu-Arg-Asp-Asp-Gly-Thr-Ser-Glu-Glu-Ser-Gly
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Q4: Which kind of chromatography should be used to purify proteins with a histidine tag? Can chaotropic agent such as urea be used to elute proteins from the column of such chromatography? Explain
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Q5: Hydrophobic interaction chromatography is often used to remove denatured proteins from a protein solution. Should you load your protein sample at high or low concentration of (NH4)2SO4? Explain
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Q6: Provide one advantage and one disadvantage of live attenuated vaccines over inactivated ones.
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Q7: Protein X is a membrane protein from a poisonous spider and is very difficult to purify. Gene for protein X has long been isolated and sequenced. Provide an approach you might use to make protein X vaccine.
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Q8: Oral intake of retrovirus expression vector is being tried for insulin production for diabetes patient, why is E.coli plasmid vector not being used for that purpose? Remember our intestine has abundant E.coli
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Q9: You have a solution mixed with four different proteins A, B, C and D. Their isoelectric points and molecular weights are calculated based on protein sequences:
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A: pl= 5.6, Mr = 28kDa
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B: pl= 7.2, Mr =35 kDa
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C: pl= 8.5, Mr = 25 kDa
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D: pl=8.6, Mr = 40 kDa
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Propose a strategy for separating these four proteins and methods for monitoring effectiveness of your separation.
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Q10: Recently a man was brought to the emergency room in Titusville, having been bitten by a pygmy rattlesnake. Rattlesnake venom is a mixture of proteins that can rapidly induce death. The patient was a gardener who worked in an area where snakes were common. He had been bitten several years previously and successfully treated with an antiserum from horses.
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Why isn’t it feasible to make human monoclonal antibodies for most snake venom?
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The antiserum treatment worked the first time; Why should you be concerned about using it again?
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Q11: You are unsure if phosphorylation is required for protein A to interact with protein B. Assume you can induce protein A phosphorylation by incubation of the cells with insulin. Assume you can purchase antibodies against A and B. Propose a protocol to test whether protein A interacts with protein B.
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Q12: After surgery, a patient is found to be infected by a bacterial that none of the antibiotics seems capable of suppressing it. Would you recommend the physician to give an injection of a vaccine or an antibody against the bacterial to help the patient? Explain
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Q13: Speculate why vortex causes protein denaturation.
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Q14: Explain why polyglutamic acid adopts an alpha-helical structure at pH 3 and random coil structure at pH 7. Similarly, polylysine adopts an alpha-helical structure at pH 10 and random coil at pH 7.
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Q15: Explain why enzymes are often stored in high concentration of glycerol solution.
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Q16: Explain why proteins still denature over time even if stored in the freezer
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Q17: How 70% ethanol denatures protein and can be used as a disinfectant
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Q18: Each of the following reagents or conditions will denature a protein. For each, describe in one or two sentences what the reagent/condition does to destroy native protein structure.
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(a) urea
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(b) high temperature
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(c) detergent
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(d) low pH
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(e) NaSCN
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Q19: Describe the changes of intramolecular and intermolecular interactions during the cooking of an egg that leads to the denaturation of proteins.
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Q20: Many human proteins when overexpressed in E.coli appear to be aggregated in the form of inclusion bodies. Speculate the cause.
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Q21: If proteases are added to the laundry detergent, will they be functional in removing protein stains on your cloth? Explain
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Q22: When injected to a patient, protein drugs produced in Eukaryotic cells often have a longer half-life than those produced in Ecoli. Explain.
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Q23: Describe the protein folding process and the change of the entropy, hydrophobic interaction, and all other weak inter- and intra- molecular interactions.
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Q24: Explain (succinctly) the theoretical and/or experimental arguments in support of this statement: “The primary sequence of a protein determines its three-dimensional shape and thus its function.”
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