Which of the following peptides is more likely to take up an α-helical structure, and why?(a) LKAENDEAARAMSEA(b) CRAGGFPWDQPGTSN

you have the following peptide Arg-Ile-Pro-Leu-Asp-Lys-Glu The net charge on this peptide at pH 7.0 is ?. The net charge on this peptide at 1M HCl is ?.

Consider a short peptide with the sequence M-C-Q-L-Y-P-E-D-K. List the ionizable groups in this peptide, and the net charge of the whole peptide at pH a) 1.5, b) 7.0, and c)12.0.

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.

How does the structure of chymotrypsin enable it to cleave only peptide bonds that are adjacent to aromatic R groups? Suppose a protease could only cleave adjacent to Lysine and Arginine; how would the structure of this protein differ from that of chymotrypsin?