X-ray Structure of Physiological Copper(II)−Bis(l-histidinato) Complex

The isolation and the X-ray crystal structure of physiological copper(II)−l-histidine complex are reported. The neutral five-coordinate
complex shows distorted square pyramidal geometry with bidentate
and tridentate l-histidine ligands. The basic character of the
pendent imidazole group and H-bonding interactions of bidentate
l-histidine ligand are important for copper transport. The unique
structural features help explain the origin of its thermodynamic stability and kinetic reactivity in human blood along with
the ternary copper(II)-amino acid complexes. The role of l-histidine
in interaction with copper(II)−albumin, in cellular uptake of copper,
and in treatment of Menkes disease can be studied using these
results.