Proline is unique in having a cyclic structure with its side chain connected to the amino group to create a secondary amine. As a consequence of its cyclic structure, Proline constrains the structure of proteins where it occurs, disrupting Alpha-helices. Isomerization between the cis and trans forms of Proline in proteins is isomerized by peptidyl-prolyl isomerases like the cyclophilins that contribute to protein folding and are components of signal transduction pathways (Ref.1).
Proline is derive...
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