TY - JOUR
T1 - Structural Characterization of the Copper Site in Galactose Oxidase Using X-ray Absorption Spectroscopy
AU - Clark, Kimber
AU - Penner-Hahn, James E.
AU - Whittaker, Mei
AU - Whittaker, James W.
PY - 1994/10/1
Y1 - 1994/10/1
N2 - X-ray absorption spectroscopy has been used to characterize the local structural environment of the Cu ion in the reductively inactivated, oxidatively activated, and active+substrate oxidation state derivatives of galactose oxidase. In all three cases, the local environment of the Cu is best modeled by a single shell of low-Z (N or O) scatterers. This is generally consistent with the structure determined crystallographically, although the EXAFS bond lengths are slightly, but significantly, shorter than those found crystallographically. The best-fit average bond lengths are 1.97, 1.95, and 1.98 Å for inactive, active, and active+substrate, respectively. The CuII ion in the active and inactive derivatives has an apparent coordination number of 4, consistent with the equatorial ligation seen crystallographically. The CuI ion in the reduced+substrate derivative appears to have either a lower coordination number or a significantly more distorted local environment. The observed CuI-N/O) bond length favors a model where the Cu becomes 3-coordinate in the substrate-reduced complex.
AB - X-ray absorption spectroscopy has been used to characterize the local structural environment of the Cu ion in the reductively inactivated, oxidatively activated, and active+substrate oxidation state derivatives of galactose oxidase. In all three cases, the local environment of the Cu is best modeled by a single shell of low-Z (N or O) scatterers. This is generally consistent with the structure determined crystallographically, although the EXAFS bond lengths are slightly, but significantly, shorter than those found crystallographically. The best-fit average bond lengths are 1.97, 1.95, and 1.98 Å for inactive, active, and active+substrate, respectively. The CuII ion in the active and inactive derivatives has an apparent coordination number of 4, consistent with the equatorial ligation seen crystallographically. The CuI ion in the reduced+substrate derivative appears to have either a lower coordination number or a significantly more distorted local environment. The observed CuI-N/O) bond length favors a model where the Cu becomes 3-coordinate in the substrate-reduced complex.
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U2 - 10.1021/bi00208a004
DO - 10.1021/bi00208a004
M3 - Article
C2 - 7918479
AN - SCOPUS:0028113463
SN - 0006-2960
VL - 33
SP - 12553
EP - 12557
JO - Biochemistry
JF - Biochemistry
IS - 42
ER -