18. Amino Acids and Proteins

What is the sequence of atoms along the 'backbone' of a protein?

How many ways can four different amino acids be arranged in a peptide so that each peptide is unique?

What atoms are present in a planar unit in a protein chain?

How many amino acid units do these atoms come from? Why are these units planar?

Bradykinin, a peptide that helps to regulate blood pressure, has the primary structure Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg.

a. Draw the complete structural formula of bradykinin.

What is meant by the following terms as they apply to protein structure, and what bonds or molecular interactions stabilize that level of structure?

a. Primary structure

Do the following peptides have an identical primary structure?