aaA aaB aaD aaC CH aaE aaF aaН aaG Spider silk (figure above left) has both strength and flexibility. As shown in the figure, it contains flexible linker regions connected to crystal regions of tightly packed beta-sheets. The sheets are tightly packed to give one "level" of the crystal structure. The linker regions contribute to the ability of spider silk to stretch. Draw a representative beta-sheet showing the backbone peptide sequence from spider silk. In your drawing include 8 amino acids (all alanine) as shown (figure above right). You can use brackets in your drawing to indicate amino acids in the beta turns. Make sure to correctly depict the stereochemistry (chirality) of the amino acids in your drawing as well as dashed lines showing opportunities for H-bonds between strands. Upload Choose a File

aaA aaB aaD aaC CH aaE aaF aaН aaG Spider silk (figure above left) has both strength and flexibility. As shown in the figure, it contains flexible linker regions connected to crystal regions of tightly packed beta-sheets. The sheets are tightly packed to give one "level" of the crystal structure. The linker regions contribute to the ability of spider silk to stretch. Draw a representative beta-sheet showing the backbone peptide sequence from spider silk. In your drawing include 8 amino acids (all alanine) as shown (figure above right). You can use brackets in your drawing to indicate amino acids in the beta turns. Make sure to correctly depict the stereochemistry (chirality) of the amino acids in your drawing as well as dashed lines showing opportunities for H-bonds between strands. Upload Choose a File

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 15QP

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Consider protein folding that results when the following components interact: Where the solution is at a pH of 7, green (thick-dotted line) represents aspartic acid (R group contains a carboxylic acid with pKa = 4), orange (thick-solid line) represents lysine (R group contains an amine with pKa = 10), and blue (thin-solid line) represents hydrophilic groups. Rank the three complexes in order from lowest to highest dissociation constants Kd (low Kd values correspond to good binding constants and low energy, while high Kd values correspond to low binding constants and high energy) as determined by intermolecular charge-charge interactions. For those complexes with charge-charge interactions being equal, look at the possibility for the formation of hydrogen bonds via carboxylic acid dimers (only possible when the carboxylic acid is protonated) which are low energy structures.
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.
Draw the polypeptide T-R-I-P at pH of 7. Label each residue with the 3-letter code, label the N- and C-termini. What is the isoelectric point of this peptide?
Two peptide segments are shown below. Predict which one would have the most negative AG when going from an unfolded to a folded structure. Justify your choice. (i) Gly-Ala-Asn-lle-Val-Trp-Leu-Glu-Met-Phe-Val-Pro OR (ii) Ala-Gly-Lys-lle-Arg-Tyr-Thr-Cys-Val-Glu-Met-Ser
Identify and encircle the peptide bonds in this polypeptide (Asp-Sec-Leu-Cys-Glu).
Amino acids project from each polypeptide backbone in a β-sheet in an alternating fashion (oneabove the plane and the next below the plane – see Fig 3.8B). Consider the following proteinsequence: Leu-Lys-Val-Asp-Ile-Ser-Leu-Arg-Leu-Lys-Ile-Arg-Phe-Glu.a. Is there a pattern to these amino acids? If so, what is it? b. What does this sequence of amino acids mean for the hydrophobicity/hydrophilicity of theresulting β-sheet? c. Can you make a prediction about how the β-sheet will be arranged in higher levels of protein structure? If so, what prediction would you make?
Draw a fractional binding curve (θ v.s [L]) for a protein binding to one molecule of L with a Kd of 10 mM.
Loop regions play important roles in the secondary structure of protein. Define loop region and give three (3) of the roles
Consider the following peptide: Lys-His-Asp-Glu-Phe-Cys-Ala-Asp-His-Arg What is the net charge of this peptide at pH = 1? What is the net charge of this peptide at pH = 14?
Peptides and small proteins fold spontaneously in aqueous solution at room temperature. Thus, for a small protein in water, we can say ΔG FOLD < 0. Denoting the unfolded protein as Unf and the folded protein as Fld, we can write the following equation:Unf(aq)--DELTA G FOLD----> Fld(aq)Considering the transition from the unfolded state (in which there are many possible conformations) to the folded state (only one conformation), there is clearly a decrease in the entropy of the protein. However, protein folding is (correctly) described as an entropically driven process.a) Resolve this apparent paradox by identifying the enthalpy (ΔH) and entropy (−TΔS)components involved in protein…
(c) The tube and cylinder diagram to the right illus- trates schematically the potassium channel protein from a bacterium. This channel protein consists of four identical polypeptide chains each comprised of 119 residues. The cyan ribbon illustrates only two of the polypeptide chains. The relative positions of 4 α-helices, one from each poly- peptide chain, are shown as cylinders. The red sphere in the central part of the diagram shows the position of a potas- sium ion identified by X-ray structure analysis. A cesium ion (green sphere) was also found to be stabilized in the same position when cesium chloride was introduced into the crys- tals. The cylinders each represent an α-helix running from Tyr62 to Thr74. Considering the position of the potassium ion, in- dicate on one of the cylinders at which end of the cylinder residue Tyr62 is found and at which end residue Thr74 is found. Explain the basis of your answer? Ala23 Thr119 (d) The N- and C-terminal residues of one of the…
A researcher performed an SDS-PAGE experiment (with 2- mercaptoethanol) on a mixture containing 3 peptides: (1) NAKQLEPDEYRTSC (2) EQCNLKGATCPSASWSGTQ (3) SCKRKA Note that I've bolded positively charged residues and underlined negatively charged residues In which of the gels below are the bands properly labeled? A |(1) (3) |(3) |(2) |(1) |(2) |(2) |(1) |(1) |(3) (+) (3) |(1) (2) |(3) |(2)