trans-4-hydroxy-L-proline => cis-4-hydroxy-D-proline
trans-4-hydroxy-l-proline => cis-4-hydroxy-d-proline
trans-4-hydroxy-L-proline => cis-4-hydroxy-D-proline
trans-4-hydroxy-l-proline => cis-4-hydroxy-d-proline