Proline
Not an amino acid...........(It is actually an imino acid!)
Due it being joined to itself back on to the nitrogen. Its molecular formula is C5H9NO2.
Proline has an aliphatic side chain, which is bonded to the nitrogen atom and the alpha-carbon atom. It influences protein architecture, because it's structure makes it more conformationally restricted than other amino acids [1].
References
- ↑ Biochemistry 6th ed. 2006, J.Berg et al