1. Shown in the first figure is the diagonal for a COSY NMR spectrum for a methionine residue. (Assume the methionine is in the middle of a polypeptide chain, and the peaks here represent an isolated spin system.) Recall that the diagonal of the COSY spectrum corresponds to the one-dimensional proton NMR spectrum.

1. Draw the chemical structure of methionine and label the N, , , , and protons on your drawing.

(Note that there are two protons and two protons that appear to be in different chemical environments and thus have different chemical shifts.)

2. Draw the expected cross peaks on the COSY spectrum. (You only need to draw the cross peaks above or below the diagonal, as the spectrum is symmetric.) Explain your thinking
3. Shown on the next figure is the diagonal for a NOESY spectrum for a methionine-alanine dipeptide. The methionine peaks are the same as in the previous question; the peaks due to the alanine protons are drawn in red.
   1. Draw the expected cross peaks in this spectrum, assuming the dipeptide is in an extended conformation. Explain your thinking

f1 Methionine H H H H NH f2 NOESY ; Methionine Alanine H H H H H NH NH f2