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
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.