4. A polypeptide comprised of 17 amino acid res- idues with the sequence on the right is ob-served by spectroscopic methods to undergo transitions from an a-helix conformation to a B-sheet as a function of pH and concentration. The acetyl and carboxamide groups are attached covalently to deri- vatize the N- and C-terminal residues, respectively, to avoid charge effects of the end CH3CO-ETATKAELLAKYEATHK-CONH2 groups. (a) (: amino acid residues. Write the sequence of this polypeptide with corresponding 3-letter abbreviations for the (b) At pH < 4 the polypeptide forms an a-helix. (i) ( . ) What is the direction of the macrodipole of the helix? and (ii) (: with respect to the positive and negative ends of the macrodipole? Are the charges on the N- and C-terminal residues stabilizing or de-stabilizing (c) ( stabilize the helical conformation. What are the most likely protonation states of the side-chains that provide a-helix stabilizing interactions? Use the helical wheel (at the back of the problem set) to identify side chain interactions that

4. A polypeptide comprised of 17 amino acid res- idues with the sequence on the right is ob-served by spectroscopic methods to undergo transitions from an a-helix conformation to a B-sheet as a function of pH and concentration. The acetyl and carboxamide groups are attached covalently to deri- vatize the N- and C-terminal residues, respectively, to avoid charge effects of the end CH3CO-ETATKAELLAKYEATHK-CONH2 groups. (a) (: amino acid residues. Write the sequence of this polypeptide with corresponding 3-letter abbreviations for the (b) At pH < 4 the polypeptide forms an a-helix. (i) ( . ) What is the direction of the macrodipole of the helix? and (ii) (: with respect to the positive and negative ends of the macrodipole? Are the charges on the N- and C-terminal residues stabilizing or de-stabilizing (c) ( stabilize the helical conformation. What are the most likely protonation states of the side-chains that provide a-helix stabilizing interactions? Use the helical wheel (at the back of the problem set) to identify side chain interactions that

Biology 2e

2nd Edition

ISBN:9781947172517

Author:Matthew Douglas, Jung Choi, Mary Ann Clark

Publisher:Matthew Douglas, Jung Choi, Mary Ann Clark

Chapter3: Biological Macromolecules

Section: Chapter Questions

Problem 16RQ: The helix and the pleated sheet are part of which protein structure? primary secondary tertiary...

See similar textbooks

Similar questions

4. A polypeptide comprised of 17 amino acid res- idues with the sequence on the right is ob-served by spectroscopic methods to undergo transitions from an a-helix conformation to a B-sheet as a function of pH and concentration. The acetyl and carboxamide groups are attached covalently to deri- vatize the N- and C-terminal residues, respectively, to avoid charge effects of the end groups. CH3CO-ETATKAELLAKYEATHK-CONH2 (а) amino acid residues. Write the sequence of this polypeptide with corresponding 3-letter abbreviations for the (b) At pH < 4 the polypeptide forms an a-helix. (i) the helix? and (ii) with respect to the positive and negative ends of the macrodipole? What is the direction of the macrodipole of Are the charges on the N- and C-terminal residues stabilizing or de-stabilizing
Draw the structure of 2 five-mers (draw backbones with side chains shown as R groups) forming a beta sheetwith two anti-parallel beta strands. Indicate the hydrogen bonds present inthissecondary structure.
1. Suppose a protein sample with a fragment containing the following amino acid sequence is subjected to various chemical assay/tests. - Ala-Gly-Trp-Phe-Met-Cys- What is observed when the protein sample is subjected to Millon’s test? Violet interface Red precipitate/solution Brown/black precipitate Yelllow product No observable result 2. Suppose a protein sample with a fragment containing the following amino acid sequence is subjected to various chemical assay/tests. - Ala-Tyr-Trp-Phe-Cys-Gly - What is observed when the protein sample is subjected to lead sulfide test? Violet interface Red precipitate/solution Brown/black precipitate Yelllow product No observable result
Show below is a polypeptide comprised of 3 α-helices and 5 β-sheets joined by randomcoil. Characterizetheforces that stabilize the tertiarystructure and draw the interacting side chains ofd) Cys Cys
Which amino acid sequence will form part of which protein structure, and why? Sequence 1: Ser-Phe-Gln-Val-Lys-Leu-His-Tyr-Asp-Val Sequence 2: Glu-Tyr-Leu-Asn-Phe-Ala-Gln-Val-Leu-Arg __Amphipathic beta strand __ Amphipathic alpha helix
ture.com/courses/7611/assignments/170598?module_itemid%3D695428 TR E Edulastic: Formativ. A Desmos | Testing O YouTube I Quiz | ReadTheory Quill.org - In О в, С, А, D D, B, A, C C, B, D, A How many nucleotides are represented in the diagram? * 2 points O 6 12 18
Page 1 > of 3 ZOOM B. Propose une Toie onsuinin Teguiaung Dioou giucose concentrauon. Question 2: Label the protein structure level on lines 1,2,3, and 4 and label/describe the structure to which each box corresponds. Describe the characteristics of each structural level in the boxes below. MacBook Air DII 80 888 F10 F7 FB F5 F4 F3 * & # $ 7 8 3 4 E R T Y K F M C V .. .. この * 00 B
27. Draw palmitic acid, identify a, B and w carbons, write out its short hand notation 28. Examine the peptide sequence below and then answer the questions: H2N-Gly- Leu- Ala-Asp-Cys-Asn-Trp-lle-Ser-Phe-Lys-Cys-Arg-Pro-coOH a. Circle the asparagine residue b. A possible intramolecular disulfide bond can be formed within this peptide between which two residues? c. Circle one residue which has a positively charged side chain under pH 7.4 d. Circle one residue which has a negatively charged side chain under pH 7.4 e. Circle the residue which can be phosphorylated
An a helix would be destabilized MOST by ○ a glycine residue adopting alpha-helical backbone dihedral angles ○ interactions between neighboring Asp and Arg residues ○ interactions between two adjacent hydrophobic Val residues O the presence of an Arg residue near the carboxyl terminus of the a helix O the presence of two Lys residues near the amino terminus of the a helix
A sample of an unknown peptide was dividedinto two aliquots. One aliquot was treated with trypsin; the otherwas treated with cyanogen bromide. Given the following sequences(N-terminal to C-terminal) of the resulting fragments, deduce thesequence of the original peptide.
The helix and the pleated sheet are part of which protein structure? primary secondary tertiary quaternary
I. A protein, X, was Isolated from a pathogenlc mlcroorganism. The proteln Is a vlrulence factor whose path0genlclty lies In a heptapeptide of unknown sequence. After trypsin cleavage of the heptapeptide from protein X, the peptlde's compOsition and sequence was determined. The fOllowing were the results of the sequenclng process: 1. When the peptide was treated with dinitrofluorobenzene (DNFB), DNP-asp and a mixture of amino acids were produced. 2. When the same Intact peptide was treated with streptococcal protease, a pentapeptide of composition asp, asN, cys, gly and ser and 2 amlno acids were released. 3. When the heptapeptlde was also treated with hydrOxylamine HCI, a tripeptide and a tetrapeptide were obtained. The C-terminal amino acid of the tripeptide was asN. 1) What is the sequence of the heptapeptide if it is composed of cys, asp, lys, asN, gly and ser only? 2) What is the pl of the heptapeptide?