Alanine has a strong tendency to form α-helix. A biochemist synthesized a polypeptide consisting of 300 alanine residues. When this polyAla300 was suspended in buffered water, it dissolved briefly and then formed a clumped insoluble precipitate that looked like cooked egg-white. Draw a cartoon (simple drawing) of the two different peptides, showing the structural organization of the polyAla300 as an insoluble precipitate, and the structural organization of the soluble (Ala30Gly5)10 polypeptid

Draw the structural formula of the oligopeptide if the amino acids are arginine, glutamine, glycine, methionine and glutamic acid considering the first amino acid is the N-terminus

In the following polypeptide, which amino acid would be participating in hydrogen bonding with alanine, given this sequence forms an alpha helix?  Please write out the full amino acid name, not the abbreviation. Met-Ala-Leu-Glu-Lys-Thr-Leu-Val

The bottom peptide segment is found in the secondary structure composed of anti-parallel - sheets. From the C-terminus of the peptide below, the sequence immediately after alternation contains the following amino acid residues (from N → C) A-F-R-M-Y-A. a) which side do you expect to face the solvent? Briefly explain your reasons NH, но Nterminus

Regarding the last answer choice, how come both alpha helices and beta sheets aren't denatured when the heat breaks peptide bonds? If heat were to break peptide bonds, wouldn't that affect the primary structure which inevitably affects the more complicated structures?

The structure of an alpha helix orients the oxygens of the carbonyl group of the peptide bond towards the C-terminal end of the helix while the hydrogens of the NH groups orient toward the N-terminal end, thus imparting a dipole along the length of the helix.  As a result, which kinds of amino acids would favor the C-terminal end, and which would favor the N-terminal end? negatively charged, positively charged positively charged, negatively charged negatively charged, hydrophobic positively charged, hydrophobic hydrophobic, negatively charged hydrophobic, positively charged

One of the most common features of anion binding sites is the presence of an a-helical structure. Using a schematic diagram of a helix, describe what you've observed. The direction of the dipole and the N-terminus of the helix should be clearly indicated. Show the (general) base structure of the glutamic acid functional group side chain.

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.

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.

You will discuss the generic G protein story the rest of your career. Explain the generic story.How do the changes, when holding various G nucleotides, impact the structure of the G-protein?