Preparation and characterization of half-apo dopamine-[beta]-hydroxylase by selective removal of Cu[sub A]. Identification of a sulfur ligand at the dioxygen binding site by EXAFS and FTIR spectroscopy

Journal Article · Tue Mar 08 23:00:00 EST 1994 · Journal of the American Chemical Society; (United States)

DOI:https://doi.org/10.1021/ja00084a037· OSTI ID:7265397

Reedy, B J; Blackburn, N J ^[1]

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1. Oregon Graduate Inst. of Science and Technology, Portland, OR (United States)

Progress has been made in determining the individual coordination of each of the copper sites (Cu[sub A] and Cu[sub B]) which comprise the active center in dopamine-[beta]-hydroxylase. Previous studies have determined the average ligand environment per copper in the fully metalated enzyme as two to three histidines and one to two O/N donors in the Cu(II) form changing to 2-3 histidines and 0.5 sulfur donors upon reduction to the Cu(I) form. Derivatives of the Cu(I) form of DBH have been made in which Cu[sub A] has been selectively removed, allowing Cu[sub B], the O[sub 2] binding center to be studied by EXAFS and FTIR. Cu[sub B] has been found to be coordinated to two histidines (Cu-N = 1.99 [+-] 0.03 [angstrom]), a S-donor ligand (Cu-S = 2.25 [+-] 0.03 [angstrom]), and a fourth, as yet unidentified ligand X (Cu-X = 2.53 [+-] 0.03 [angstrom]). The FTIR spectrum of the carbonyl derivative of Cu[sub B] indicates that V[sub CO] (2089 cm[sup [minus]1]) is identical to that found for the fully metalated enzyme, providing strong evidence that the Cu[sub B] site is not perturbed by Cu[sub A] removal. EXAFS results on Cu[sub B]-CO indicate that CO binding does not displace the S ligand but appears to displace the weakly bound ligand X. 44 refs., 4 figs., 3 tabs.

• OSTI ID: 7265397
• Journal Information: Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 116:5; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ABSORPTION SPECTROSCOPY
AMINO ACIDS
AZOLES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
COMPILED DATA
COMPLEXES
COPPER COMPLEXES
DATA
ENZYMES
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HISTIDINE
HYDROXYLASES
IMIDAZOLES
INFORMATION
INFRARED SPECTRA
LIGANDS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PROTEINS
SPECTRA
SPECTROSCOPY
STOICHIOMETRY
TRANSITION ELEMENT COMPLEXES
X-RAY SPECTROSCOPY