A cyclodecapeptide ligand to vitamin B12.

Libraries of cyclic decapeptides were screened with vitamin B12 derivs. to give cyclic peptide ligands incorporating histidine and cysteine as coordinating residues and neg. charged amino acids. Two hits, cyclo(His-Asp-Glu-Pro-Gly-Ile-Ala-Thr-Pro-D-Gln) and cyclo(Val-Asp-Glu-Pro-Gly-Glu-Asp-Cys-Pro-D-Gln) were resynthesized in good yields for soln. expts. The peptides bind aquocobalamin with coordination of His or Cys to the cobalt with high affinities (Ka ∼ 105 M-1). Addnl. interactions between the peptide side chains and the vitamin B12 corrin moiety were detd. by studying the 1H NMR soln. structure. The cyclopeptide-cobalamin complex with the histidine residue showed enhanced stability towards cyanide exchange, demonstrating the shielding effect of the ligand on the metal center. [on SciFinder(R)]

Références

Titre
A cyclodecapeptide ligand to vitamin B12.
Type de publication
Article de revue
Année de publication
2008
Revue
Org. Biomol. Chem.
Volume
6
Pagination
4134–4141
ISSN
1477-0520
Soumis le 12 avril 2018