Characterization of copper-nickel and silver-nickel bovine superoxide dismutase by /sup 1/H NMR spectroscopy

Journal Article · Wed Nov 30 04:00:00 EST 1988 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00297a024· OSTI ID:5762004

Ming, L; Banci, L; Luchinat, C; Bertini, I; Valentine, J

Nickel(II) substitution for Zn/sup 2+/ in bovine Cu,Zn-superoxide dismutase has provided information concerning the configurational and spectroscopic properties of Ni/sup 2+/ in the zinc site and also of Cu/sup 2+/ in the copper site. The effective electronic relaxation time of Cu/sup 2+/ in this derivative is greatly decreased from 2 /times/ 10/sup /minus/9/ s in native protein to about 3 /times/ 10/sup /minus/12/ s by the magnetic coupling between the paramagnetic Ni/sup 2+/ and Cu/sup 2+/ ions. Consequently, an isotropically shifted /sup 1/H NMR spectrum of this species has been obtained, consisting of resonances from amino acid residues bound to both metal ions. On the basis of azide titration and proton relaxation time measurements on this species, a full assignment of the isotropically shifted signals is presented. The smaller nuclear relaxation rates of the histidyl protons and the smaller differences in the relaxation rates between ortho-like and meta-like protons of the coordinated histidine residues in the copper site in Cu/sub 2/Ni/sub 2/SOD as compared to those in Cu/sub 2/Co/sub 2/SOD result from different correlation times and different contributions of relaxation mechanisms in these two derivatives. A reasonable physical picture of proton relaxation in this magnetically coupled system is proposed, and a theoretical fitting is reported. A comparison of the spectra and relaxation rates of this derivative and of M/sub 2/Ni/sub 2/SOD (M = Ag/sup +/, Cu/sup +/) has provided further information on the bridging ligand and on the relaxation mechanisms. 28 refs., 6 figs., 3 tabs.

• Research Organization: Univ. of California, Los Angeles (USA)
• OSTI ID: 5762004
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 27:24; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
ANIMALS
BARYONS
CATTLE
COPPER COMPOUNDS
DATA
DEUTERIUM
DOMESTIC ANIMALS
ELECTRONIC STRUCTURE
ELEMENTARY PARTICLES
ENZYMES
EXPERIMENTAL DATA
FERMIONS
HADRONS
HYDROGEN ISOTOPES
INFORMATION
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
MAMMALS
NMR SPECTRA
NUCLEI
NUCLEONS
NUMERICAL DATA
ODD-ODD NUCLEI
OXIDOREDUCTASES
PROTONS
RUMINANTS
SPECTRA
STABLE ISOTOPES
SUPEROXIDE DISMUTASE
TRACER TECHNIQUES
TRANSITION ELEMENT COMPOUNDS
VERTEBRATES
ZINC COMPOUNDS