Compositions and conformations of several transition metal complexes with a nonapeptide hormone oxytocin

Citation
H. Wei et al., Compositions and conformations of several transition metal complexes with a nonapeptide hormone oxytocin, J CHEM S DA, (22), 2000, pp. 4196-4200
Citations number
35
Categorie Soggetti
Inorganic & Nuclear Chemistry
Journal title
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
ISSN journal
1470479X → ACNP
Issue
22
Year of publication
2000
Pages
4196 - 4200
Database
ISI
SICI code
1470-479X(2000):22<4196:CACOST>2.0.ZU;2-0
Abstract
Similar co-ordination characteristics of oxytocin (OT) towards Cu-II, Ni-II , Mn-II and Zn-II at different pH values have been demonstrated by electros pray mass spectrometry (ESMS) and rationalized by molecular mechanics simul ation. At ca. pH 2 oxytocin does not interact with the metal ions; at pH 5 species with metal bound oxytocin were detected, including [OT+H+](+), [M+O T](2+), [M+OT-H+](+), [M+OT+ClO4-+H+](2+) and [M+OT+ClO4-](+) and only stab le 4N complexes were found at pH approximate to9. Molecular modelling studi es using the Universal force field (UFF) showed that the four N-donor cente rs of oxytocin prefer the square planar geometry in complexes of Ni-II and Mn-II. For Pd-II, the S gamma (1) co-ordinated conformer was found to be mo re stable than the S gamma (6) co-ordinated one. Dramatic conformational ch anges occur upon oxytocin co-ordinating to Ni-II, Mn-II or Pd-II.