2. A mutation that changes an alanine residue in the interior of a protein to valine (A157 → V157) is found to lead to aloss of proper folding and activity. However, proper folding and activity are regained when a second mutation at adifferent position changes a leucine residue to glycine (L185 G185). Based on these observations, you→hypothesize that amino acid residues 157 and 185 are spatially close to each other in the folded and activeprotein. How does your hypothesis explain the data, that the double mutant (A¹57 → V157; L185 → G185) has activitythat the single mutant (A¹57 → V157) lacks?

Different protein gain its three dimensional structure after folding, which occurs according to the…

Answered: 2. A mutation that changes an alanine…

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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Similar questions

On the basis of the information provided in Figure 9.17, complete the mechanisms for peptide-bond cleavage by (a) a cysteine protease, (b) an aspartyl protease, and (c) a metalloprotease.
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Consider an amino acid sequence: D1-G2-M3-E4-C5-A5-F7-H8-R9-I10-A11-H12-T13-Y14-G15-F16-P17-E18-A19-A20-M21-C22-K23-W24-E25-A26-Q27-P28 The β-turn structure is likely found at (Write down the residue number). A possible disulfide bond is formed between the residues and . The total number of basic residues are The addition of chymotrypsin will result in blank peptide fragment(s). The addition of trypsin will result in blank peptide fragment(s). The addition of CNBr will result in blank peptide fragment(s).
1. What is the length in AA’s of the LilP protein? Assume fMet is NOT CLEAVED. 2. Write out the sequence of the polypeptide in AA: use the three letter notation, e.g. Met-Ser-Pro-
2. The diagram to the right shows the change in the structure of the C-terminal portion of each of the ẞ-subu- nits of human hemoglobin (HbA) in the oxyHb to deox- yHb or R-to-T transition. The hydrogen bonding interac- tion of the C-terminal ẞHis 146 residue with the side chain of Asp94, highlighted by the red ellipse, has been shown to be responsible for a major portion of the proton uptake associated with the Bohr effect. Treatment of HbA with the enzyme carboxypeptidase A (CPA) results in loss of the C-terminal ẞHis 146 and ẞTyr145 residues of the ẞ- subunits. (a) ( ) Draw a Hill plot [log(Y/[1-Y]) vs. log(pO2), Y = fraction of heme groups occupied by O2] to compare the values of the Hill coefficient nн and the O2-binding affinity at pH 7.4 of normal HbA before and after treat- ment of with CPA. (b) (' ) How will the plot for CPA-digested HbA change at pH 7.2? (c) 1 Hi5146 HN- ✓ Low PK B-chain. CH2 CH-NH-CO-CH-NH- CH₂ Tyr145 он HbO2 or R state Туг145 CH-CH2- OH co NH CH CH₂ His…
Val (V) Ala (A) Arg (R) Ser (S) Lys (K) Start Stop Using the codon wheel below, identify which of the following mutations of the DNA sequence TTT TAC ACT would potentially have the least effect on the protein containing the sequence? Asp (D) G A JOOGA C Asn (N) اندان A داد Glu (E) 9/2/3. 20402 CAGUCAGUCAGUC GU ט|כ Thr C U G G A Gly A A Phe (F) C/U/G ●Met (M) Leu (L) GU AC C CUGA GACUGA ACUGACUG A Arg (R) G כט Ser (S) C U с Gin (Q) A G U C A G બનીનો His (H) Tyr (Y) U G C Cys (C) Pro (P) Trp (W) Leu (L) A) TTA TAC ACT B) TTT TTC TCT C) TTT TAC TGA D) TAA AAC AGA E) They would all have the same effect.
2. Chymotrypsin, trypsin, and elastase are members of a family of enzymes referred to as serine proteases. The enzyme papain (found in papaya) is also a protease but is a member of a family of enzymes referred to as cysteine proteases. The amino acid residues in the active site of papain critical for peptide bond hydrolysis are a protonated histidine and a deprotonated cysteine residue. The cysteine residue functions as the nucleophile similarly to the serine residue in serine proteases. (a) Using what you know about chymotrypsin's mechanism, draw a reaction mecha- nisn for the hydrolysis of a peptide bond by papain. Does the mechanism you have drawn employ acid-base catalysis, covalent catalysis, (b) or both? (c) The pKa values of the active site residues that control the pH profile of the activity of pa- pain are 4.2 and 8.2. The pH optimum for the reaction is 6.0. Through the many years of re- search carried out on cysteine proteases, it has been demonstrated that the pKa of 4.2…
Bovine insulin is composed of two polypeptide chains that are linked together covalently. The two chains have the following sequences: GIVEQCCASVCSLYQLENYCN - A chain FVNQHLCGSHLVEALYLVCGERGFFYTPKA - B chain a. Through which amino acids are these two chains linked together covalently? b. How many different ways can these two chains be linked? c. Of the different connectivities you enumerated in part b, which is the biologically active form?
4. You're working on a structure of a protein and its folding. You think that the interaction between Asp123 and Arg29 is important in determining the structure of the protein. a) What type of amino acid is Asp (acidic, basic, hydrophobic, or polar)? b) What type of amino acid is Arg (acidic, basic, hydrophobic, or polar)? c) What is the strongest interaction that can form between Asp123 and Arg29? You create a mutant Arg29> Lys d) What type of amino acid is Lys (acidic, basic, hydrophobic, or polar)? e) Would you expect this substitution mutation to cause major folding problems? Why or why not? You create mutant Arg29> Glu you discover that this mutant is unable to fold properly, so the protein is nonfunctional. f What type of amino acid is Glu (acidic, basic, hydrophobic, or polar)? g) How does this amino acid substitution cause the protein to fold incorrectly? You find another mutant that also as the same Arg29> Glu mutation. However, this mutant protein įs able to fold normally.…
1.Draw these phosphorylated structures as they would be connected in a polinucleotide (e.g.RNA) in the order A-B. / Show how they combine to form the polynuleotide (i.e. only the end product). Show at any one of these structures where the glycosidic bond occurs 2.Sanger sequencing revealed the sequence of an oligonucleotide to be: d-AGATGCCTGACT. Draw a diagram of the gel banding pattern post capillary electrophoresis i.e. where on the gel would the fragments feature
9. Shown below is a binding pocket for a protein with a ligand bound. The ligand interacts with a serine and a valine side chain. ligand a. Briefly explain, in terms of Ka, the effect of a mutation that replaces the serine residue with a valine residue. b. Briefly explain, in terms of Kd, the effect of a mutation that alters the ligand (as seen below) binding to the original, unmutated, binding site. :0: ligand 2
Propose one amino acid substitution that would disrupt the leucine zipper structure and explain why

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