Copper sites of dopamine. beta. -hydroxylase: an X-ray absorption spectroscopic study

Journal Article · Tue Jul 26 04:00:00 EDT 1988 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00415a005· OSTI ID:7186938

Scott, R A; Sullivan, R J; DeWolf, Jr, W E; Dolle, R E; Kruse, L I

X-ray absorption edge and extended X-ray absorption fine structure (EXAFS) spectra are reported for the Cu(I) and Cu(II) forms of bovine dopamine ..beta..-hydroxylase and for the Cu(I) form of DBH bound either to tyramine substrate or to a multisubstrate inhibitor. A significant change in the structure of the copper sites occurs upon ascorbate-mediated reduction of Cu(II) DBH to the Cu(I) form. While the average Cu(II) site most likely consists of a square-planar array of four (N,O)-containing ligands at 1.98 A, the average Cu(I) site shows a reduction in (N,O) coordination number (from approx. 4 to approx. 2) and the addition of a S-containing ligand at 2.30 A. No change in the average Cu(I) ligand environment accompanies binding of tyramine substrate, whereas binding of a multisubstrate inhibitor, 1-(3,5-difluoro-4-hydroxybenzyl)-1H-imidazole-2(3H)-thione, causes an increase in the Cu-S coordination, consistent with inhibitor binding to the Cu(I) site through the S atom. Although excellent signal-to-noise ratio in the EXAFS spectra of ascorbate-reduced DBH facilitated analysis of outer-shell scattering for a Cu...Cu interaction, the presence of a binuclear site could not be proven or disproven due to interference from Cu...C scattering involving the carbons of imidazole ligands.

• Research Organization: Univ. of Georgia, Athens (USA)
• OSTI ID: 7186938
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 27:15; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550602* -- Medicine-- External Radiation in Diagnostics-- (1980-)
62 RADIOLOGY AND NUCLEAR MEDICINE
ADRENAL GLANDS
ADRENAL HORMONES
AMINES
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
CATTLE
CHROMATOGRAPHY
COPPER COMPOUNDS
COPPER SULFATES
DOMESTIC ANIMALS
DOPAMINE
DRUGS
ENDOCRINE GLANDS
ENZYME ACTIVITY
ENZYMES
GLANDS
HYDROXY COMPOUNDS
HYDROXYLASES
ION EXCHANGE CHROMATOGRAPHY
LIQUID COLUMN CHROMATOGRAPHY
MAMMALS
NEUROREGULATORS
NORADRENALINE
ORGANIC COMPOUNDS
ORGANS
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PHENOLS
POLYPHENOLS
RUMINANTS
SEPARATION PROCESSES
SIGNAL-TO-NOISE RATIO
SPECTROSCOPY
SULFATES
SULFUR COMPOUNDS
SYMPATHOMIMETICS
TRANSITION ELEMENT COMPOUNDS
VERTEBRATES
X-RAY SPECTROSCOPY