Characterization of the blue copper site in oxidized azurin by extended x-ray absorption fine structure: Determination of a short Cu—S distance

Abstract
The primary coordination environment of the blue Cu ion in oxidized azurin [from Pseudomonas aeruginosa] was elucidated by X-ray absorption spectroscopy. The most striking feature is the unambiguous presence of a very short Cu-S distance at 2.10 .+-. 0.02. N ligands, presumed to be from imidazoles, are found at 1.97 .ANG.. There is some evidence that the Cu coordination sphere may be completed by a 2nd S, the distance of which is determined with much less certainty.