Which primary amino acid sequences most likely represents an alpha helix stabilized by ionic interactions between R groups at a pH = 5? (A) Ala-Val-Gly - Ile - Leu (B) Asn- Ile-Met - Ser - Pro (C) His-Gly - Asp - Arg - Val (D) Lys-Phe-Leu-Asp - Met

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.

What is the net electric charge of a peptide that has the sequence and provide the one letter code if you can Glu-His-Ser-Gly-Leu-Arg-Pro-Gly at pH 3, and 11

(A) Give the polypeptide translation of the RNA sequence below. 5’-AUGGAAAUCAAAGUCAACCUUGAGUUUAGA-3’ (B) Write the chemical structure of the polypeptide sequence you determined in part (a) (C) Given the chemical structure of the polypeptide sequence you have written in part (b), answer True or False for each of the 5 statements below. (1) At least one of the amino acids in the sequence can undergo phosphorylation (2) The sequence looks like it could form a β turn (3) The sequence looks like it could form a β strand with one surface facing the interior of the protein and the other surface exposed to water (4) At least one of the amino acids in the polypeptide sequence can undergo oxidation to form a disulfide bridge to another polypeptide (5) The sequence looks like it could form an α helix that would be part of a coiled coil structure within a protein