Question

1. The R domains of the amino acids that differ between human and duck insulin.

2. A list of at least 4 intra-helix H bonds and 2 interchain H bonds.

Please help me, thank you so much!

Answer 1

SOLUTION:

1.

Human insulin has Thr-Ser-Ile-Phe-Val-Thr amino acids at positions A8-A10 and B1, B2 and B27 while duck insulin has Glu-As-Pro-Ala-Ala-Ser at the same positions which means there are more acidic amino acids (R domains) in the duck insulin than that of human.

2.

During protein folding, the burial of hydrophobic side‐chains requires intramolecular hydrogen bonds to be formed between the main chain polar groups. The most stable conformations of polypeptide chains that maximize intrachain hydrogen‐bonding potential are the alpha helices and beta pleated sheets.

The alpha helix hydrogen bonds formed in the secondary structure of a protein is an intrachain hydrogen bond because all of the hydrogen and carbonyl oxygen atoms of the peptide backbone can interact to form intrachain hydrogen bonds.

The ball-and-stick model of a right-handed alpha-helix protein shows intrachain hydrogen bonding. In the beta-sheet conformation of a protein, the hydrogen bonds can be either intrachain, or interchain between the peptide linkages of adjacent polypeptide chains. All the peptide linkages of beta-keratin participate in interchain hydrogen bonding.