title: Effect of tetrazole moiety on coordinating efficiency of deltorphin.
abstract: A study of the effect of the tetrazole moiety, a cis-amide bond surrogate, on the Cu(II) coordinating properties of oligopeptides is reported. Insertion of the tetrazole moiety Psi[CN(4)] into the peptide sequence of [D-Ala(2)]deltorphin I changes considerably the coordination ability of the peptide. Potentiometric and spectroscopic results show that if the tetrazole moiety is in a suitable position in the peptide chain, i.e. it follows the second residue, a stable CuL species involving 3N coordination is formed in the physiological pH range. The tetrazole Psi[CN(4)] ring provides one of these nitrogens. The data indicate that Cu(II) ions are strongly trapped inside a bent peptide backbone. The peptide conformation changes achieved by Cu(II) coordination may be essential for the binding of tetrazole deltorphins at opiate receptors.
authors.affiliation: Institute of General Food Chemistry, Technical University of Łódź, Łódź, Poland. elalodyg@p.lodz.pl
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Łodyga-Chruścińska
authors.forename: Stanisław
authors.initials: S
authors.lastname: Ołdziej
authors.forename: Giovanni
authors.initials: G
authors.lastname: Micera
authors.forename: Daniele
authors.initials: D
authors.lastname: Sanna
authors.forename: Longin
authors.initials: L
authors.lastname: Chruściński
authors.forename: Jacek
authors.initials: J
authors.lastname: Olczak
authors.forename: Janusz
authors.initials: J
authors.lastname: Zabrocki
mesh_terms: D000577:Amides / Q000737:chemistry; D000595:Amino Acid Sequence; D001665:Binding Sites; D002942:Circular Dichroism; D003300:Copper / Q000378:metabolism; D004355:Drug Stability; D007700:Kinetics; D009842:Oligopeptides / Q000737:chemistry* / Q000378:metabolism; D011199:Potentiometry; D013053:Spectrophotometry; D013777:Tetrazoles / Q000737:chemistry*
chemical_list: D000577:Amides; D009842:Oligopeptides; D013777:Tetrazoles; C059567:deltorphin; C060208:deltorphin I, Ala(2)-; D003300:Copper