Possible insights into metal ion recognition in calcium-binding proteins provided by complexing properties of ligands containing amide oxygen donors.
The formation constants of the ligand N,N,N',N'-tetrakis(carbamoylmethyl)-ethylenediamine suggest that the amide oxygen is a stronger Lewis base in water than the alcoholic oxygen, or water, and that part of the selectivity for Ca2+ over Mg2+ shown by calcium-binding proteins such as calmodulin or annexin may be due to the higher affinity of Ca2+ for the O-donor of the Ca-binding amide groups present in such proteins.
Siddons
Chynthia J
CJ
Department of Chemistry and Biochemistry, University of North Carolina at Wilmington, Wilmington NC 28403, USA.
Hancock
Robert D
RD
D001665:Binding Sites; D002118:Calcium / Q000737:chemistry*; D002135:Calcium-Binding Proteins / Q000737:chemistry*; D008024:Ligands; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D010100:Oxygen / Q000737:chemistry
D002135:Calcium-Binding Proteins; D008024:Ligands; D008670:Metals; D010100:Oxygen; D002118:Calcium