Oxytocin-receptor binding: why divalent metals are essential.
Biologists have observed that the presence of divalent metal is essential for the binding of the hormone oxytocin (OT) to its cellular receptor. However, this interaction is not understood on the molecular level. Because conformation is a key factor controlling ligand binding in biomolecule systems, we have used ion mobility experiments and molecular modeling to probe the conformation of the oxytocin-zinc complex. Results show that Zn2+ occupies an octahedral site in the interior of the OT peptide that frees the N-terminus and creates a structured hydrophobic binding site on the peptide exterior; both factors are conducive to binding oxytocin to its receptor.
Liu
Dengfeng
D
Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, USA.
Seuthe
Alexandra B
AB
Ehrler
Oli T
OT
Zhang
Xiaohua
X
Wyttenbach
Thomas
T
Hsu
Jeffrey F
JF
Bowers
Michael T
MT
D002413:Cations, Divalent; D008958:Models, Molecular; D010121:Oxytocin / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D018045:Receptors, Oxytocin / Q000737:chemistry* / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D013816:Thermodynamics; D015032:Zinc / Q000737:chemistry* / Q000378:metabolism*
D002413:Cations, Divalent; D018045:Receptors, Oxytocin; D010121:Oxytocin; D015032:Zinc