Draw the full structure of the one predominant form of val-asp-asp-arg fragment as it would exist at pH 7.4?

With the aid of the simple generic diagram, identify and explain how the type of chemical bonding stabilizes a secondary structure present in 3GRS (glutathione reductase).

Draw the tetrapeptide Met-Ile-Lys-Glu at a ph of 7?

Polylysine adopts a random structure in solution at physiological pH (i.e. 7.4). Given that the e-amino group of lysine has a pKa of 10.5, under what circumstances do you think polylysine will form an a-helix? Give an explanation for your decision.   Given the pKa of the side-chain COOH group, under what circumstances would you anticipate polyglutamate to form an a-helix?

Hemoglobin is considered to be a tetrameric complex with a 64 kDa (α β)2. When attempting to purify hemoglobin, we must first purify the α and β monomers (about 16 kDa each) to prepare the tetramer. This is formed from the dimer intermediate: 2 α + 2 β -> 2 αβ -> (α β)2. The graph given represents a size-exclusion chromatogram after the refolding of the hemoglobin tetramer Using the size-exclusion chromatogram given, 1.  Draw an SDS-Page Gel with a reducing agent such as BME using the three peaks listed on the graph.

Consider the phenolic hydroxyl group of a particular Tyr residue in a protein. Suppose the hydroxyl group in the unfolded protein in aqueous solution, where the group is exposed to H2O, has a pKa of 10.0. If that group is found in a hydrophobic environment in the interior of the protein when the protein is folded into its native tertiary structure, would you expect the pKa of the phenolic hydroxyl to be higher or lower in the folded protein interior than in H2O? Explain your reasoning.

The last residue of the protein (tail) is Tryptophan, and the first residue (head) is labeled with IAEDANS acceptor. Estimate the length of the protein (head to tail) if the efficiency of RET measures at 0.01 Please show step by step and how to get the 34.014 number

Proline is one of the amino acids in the "special" groups of sidechains. One reason for this is the dramatic impact it can have on secondary structure.  a) draw the lewis structure for a tripeptide with the sequence Ala-Pro-Ala b) Proline residues are rarely found in alpha helices - in fact, they are often referred to as helix-disrupting amino acids. Thinking about intermolecular interactions, provide an explanation for why proline might disrupt alpha-helices. c) Proline also has a similar effect on beta-sheets, and is rarely found in the middle of beta sheets. Thinking about noncovalent interactions, provide an explanation for why proline might disrupt beta-sheets.

Identify the structure of the predominant form of the pentapeptide at pH = 12 if there is a pentapeptide Ile-Lys-Asp-Phe-Gly

6  (a) A decapeptide has the following amino acid composition: Ala2 , Arg, Cys, Glu, Gly, Leu, Lys, Phe, Val Partial hydrolysis yields the following tripeptides: Cys-Glu-Leu + Gly-Arg-Cys + Leu-Ala-Ala+ Lys-Val-Phe + Val-Phe-Gly. Reaction of the decapeptide with 2,4-dinitrofluorobenzene yields 2,4-dinitrophenylysine. From the experimental data, deduce the primary structure of the decapeptide. (b) Suggest a scheme you will follow to synthesize the dipeptide Ala-Gly