(3R,4S)-3,4-dihydroxy-L-proline residue
(3r,4s)-3,4-dihydroxy-l-proline residue
An <small>L</small>-proline residue that is substituted by hydroxy groups at positions 3 and 4 (the 3<i>R</i>,4<i>S</i> diastereoisomer).