4. Cis peptide bonds are rarely found in proteins because they are about 8 kJ/mole less stable than the trans isomer. However, in the rare instances where they are present, they are followed by a Pro residue. In fact, about 10% of the proline residues in proteins are found following a cis peptide bond. Why would a Pro following a cis peptide bond make a difference

4. Cis peptide bonds are rarely found in proteins because they are about 8 kJ/mole less stable than the trans isomer. However, in the rare instances where they are present, they are followed by a Pro residue. In fact, about 10% of the proline residues in proteins are found following a cis peptide bond. Why would a Pro following a cis peptide bond make a difference

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter9: Gene Expression And Gene Regulation

Section: Chapter Questions

Problem 19QP: Below is the structure of glycine. Draw a tripeptide composed exclusively of glycine. Label the...

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The first and major effect in denaturation of proteins is that: a. peptide bonds break. b. helices unwind. c. sheet structures unfold. d. tertiary structure is changed. e. quaternary structures disassemble.
Below is the structure of glycine. Draw a tripeptide composed exclusively of glycine. Label the N-terminus and C-terminus. Draw a box around the peptide bonds.
1. a. Draw the following pentapeptide: lysine-leucine-aspartate-threonine-phenylalanine b. Label the amino and carboxyl terminus of your peptide c. Label each amino acid residue with one and three letter abbreviations d. Label the alpha carbons e. Label the bonds around which phi and psi rotational angles occur f. Which amino acid in this chain is most likely to be phosphorylated? Which amino acid is most likely to be acetylated?
4. What is the net charge (approximately) on the polypeptide shown below at pH 12.5? Lys - Arg - Val-Cys - Glu
2. a. In the following diagram of a portion of a protein, label the types of interactions that are shown. b. What level of protein structure are these interactions producing? b. CH CH3 CH3 Polypeptide backbone CH2 H3C H3Ç 10 CH С—ОН - CH,-S-S-CH,- а. CH2 с. -CH,-CH,-CH2-CH2-NH 0-C-CH2- d.
4. The molecular structure of the last 12 amino acid residues (dodecapeptide) that comprise the C- terminal segment of semaglutide is shown below. NH₂ H₂N NH HO NH NH CH 3 NH CH3 CH 3 NH NH ΝΗ CH3 CH3 O NH H3C NH CH3 a) Determine the sequence of the dodecapeptide in one-letter code: b) Convert your sequence in (a) into three-letter code: H₂N. NH NH NH NH H₂N NH NH NH Im c) How many of the a-carbons in this peptide sequence are chiral? d) How many peptide bonds are in this peptide? e) Predict the overall charge of this peptide at physiological pH. f) A biochemist synthesized the C-terminal dodecapeptide version of semaglutide but found that there were other contaminating peptides. Based on your answer in (4.e), which ion exchange chromatography technique would you use to effectively purify the dodecapeptide from the mixture? (encircle one) anion exchange cation exchange g) Briefly explain your answer in (4.f).
6. b. Draw a box around the disulfide bridge in oxytocin, if present, or write "none". 7. Mark each peptide bond in oxytocin by making the corresponding line in the structure thicker or marking it with a different color. The first one is shown for you as an example (in dark orange). 8. Number the central carbon of each amino acid in oxytocin by pointing a small arrow to it or by circling the corresponding vertex in the image. Numbers 1 and 2 indicate the central carbons of the first and second amino acids of oxytocin, and are shown for you as an example. 9. Fill out the following table, listing amino acids that make up oxytocin in order, from the N terminus to the C terminus, characterizing each amino acid by the properties of its R group (side chains), and briefly indicating the reasoning for the characterization. You may consult amino acid groupings by category in the slides (or the textbook, p.49), but you must explain the reasoning for each in your own words. CO 1 AA# Abbre- Full…
1.a.If this molecule was the side chain of an amino acid, in a protein, what tertiary structure stabilizers could be present? b.Make a key and use color to highlight what part of you structure can be stabilized in each manner?
1. What will happen if there is a change in the configuration of a protein molecule? Provide an example. 2. Give the IUPAC name for Ala-Gly-Leu
3. A. Briefly discuss the four levels of structure in proteins. Knowing that the 3-dimensional shape of a protein is important to its function, discuss on a qualitative basis whether the changes below will likely alter the function of a protein, justifying your answer with why or why not. B. What would happen to a protein's functionality if a serine residue were replaced with threonine? C. What would happen if serine were replaced with leucine? D. What would happen if serine were replaced with cysteine? E. What would happen if aspartic acid were replaced with tryptophan in the part of the protein (an enzyme) that serves as an active site to catalyze a reaction? F. What would happen if aspartic acid were replaced with tryptophan in a non-active site?
4) For various amino acid pairs (for example: F to A, E to R, D to N, V to L, S to W), ask yourself: a) Based on what you know about the chemical properties of the side chains, what effect would you expect on the stability of the protein if you mutated one residue of the pair into the other in the interior of the protein? What forces might have an impact on this change (ie: what types of interactions would you expect that amino acid to be involved in?) How would your answer change if the amino acid were located on the surface of the protein? b) c)
7. Identify the primary structure of a hexapeptide containing five different amino acids if the following smaller peptides are among the partial hydrolysis products: Gly-Cys, Ala-Ser, Ala-Gly, and Cys-Val-Ala