The synthesis, physical and analytical characterization, and crystal‐state structural analysis by X‐ray diffraction of three analogues of the Nα‐acylated tripeptide amide tail of oxytocin, each containing a cyclic Cα, α‐ disubstituted glycine at position 2, have been performed. The peptides arc Boc‐L‐Pro‐Ac3c‐Gly‐NH2, Z‐L‐Pro‐Ac5c‐Gly‐NH2 and Z‐L‐Pro‐Ac5c‐Gly‐NH2. While the former is folded in a type‐II β‐turn conformation at the ‐L‐Pro‐Ac3c‐ sequence, the two latter tripeptides form two consecutive (type‐II, type‐I′) β‐turns. The Ac5c‐ and Ac6c‐tripeptides are the first examples of such a highly folded structural combination in a position‐2 analogue of the Nα‐acylated ‐L‐Pro‐L‐Leu‐GIy‐NH2 sequence. Copyright © 1993, Wiley Blackwell. All rights reserved
Conformational versatility of the Nα‐acylated tripeptide amide tail of oxytocin: Synthesis and crystallographic characterization of three C2α‐backbone modified, conformationally restricted analogues
ISERNIA, Carla;
1993
Abstract
The synthesis, physical and analytical characterization, and crystal‐state structural analysis by X‐ray diffraction of three analogues of the Nα‐acylated tripeptide amide tail of oxytocin, each containing a cyclic Cα, α‐ disubstituted glycine at position 2, have been performed. The peptides arc Boc‐L‐Pro‐Ac3c‐Gly‐NH2, Z‐L‐Pro‐Ac5c‐Gly‐NH2 and Z‐L‐Pro‐Ac5c‐Gly‐NH2. While the former is folded in a type‐II β‐turn conformation at the ‐L‐Pro‐Ac3c‐ sequence, the two latter tripeptides form two consecutive (type‐II, type‐I′) β‐turns. The Ac5c‐ and Ac6c‐tripeptides are the first examples of such a highly folded structural combination in a position‐2 analogue of the Nα‐acylated ‐L‐Pro‐L‐Leu‐GIy‐NH2 sequence. Copyright © 1993, Wiley Blackwell. All rights reservedI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
