Effect of tetrazole moiety on coordinating efficiency of deltorphin.
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.
Łodyga-Chruścińska
Elzbieta
E
Institute of General Food Chemistry, Technical University of Łódź, Łódź, Poland. elalodyg@p.lodz.pl
Ołdziej
Stanisław
S
Micera
Giovanni
G
Sanna
Daniele
D
Chruściński
Longin
L
Olczak
Jacek
J
Zabrocki
Janusz
J
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*
D000577:Amides; D009842:Oligopeptides; D013777:Tetrazoles; C059567:deltorphin; C060208:deltorphin I, Ala(2)-; D003300:Copper