The crystal structure of the pGlu-Pro-NH2 dipeptide, cis-1-(5-oxo-L-prolyl)-L-prolinamide hydrate [cis-1-(5-oxo-L-prolyl)pyrrolidine-2-carboxamide hydrate], C10H15-N3Oa.H2O, has been determined in order to establish the conformation of the pyrrolidine ring both in natural (L) proline (Pro) and in pyroglutamic acid (pGlu), a cyclic analogue of the the natural L-glutamate amino acid. The structure was solved by direct methods and refined by least-squares calculations to a final R value of 0.026. While the pyrrolidine ring of the Pro residue adopts a twisted conformation, this ring is planar in the pGlu amino acid. The proline residue is in a cis orientation with respect to the peptide bond. Molecular cohesion is stabilized by a dense network of hydrogen bonds involving the free amine group of pGlu, the three O atoms of the carbonyl groups, the terminal carboxy-protective NH2 group and a water molecule.
|Pages (de - à)||477-480|
|Nombre de pages||4|
|journal||Acta crystallographica Section C: Crystal Structure communications|
|Numéro de publication||4|
|Etat de la publication||Publié - 15 avr. 1997|