scholarly journals An e.p.r. study of the non-equivalence of the copper sites of caeruloplasmin

1986 ◽  
Vol 238 (1) ◽  
pp. 291-295 ◽  
Author(s):  
L Calabrese ◽  
M Carbonaro
Keyword(s):  
Slow Phase ◽  
Copper Binding ◽  
Blue Copper ◽  
Sequence Of Events ◽  
Copper Site ◽  
Hyperfine Splitting Constant ◽  
Type 1 Copper ◽  
Splitting Constant

The two Type 1 (blue) copper-binding sites of caeruloplasmin were spectroscopically differentiated by the kinetic analysis of the e.p.r. spectra during the redox cycle. One blue copper, with a hyperfine splitting constant (A parallel) of 6.8 mT, which was rapidly reduced, was not reoxidized by oxygen, whereas it was reoxidized by H2O2. The other blue copper (A parallel = 5.8 mT), which was reduced slowly, was rapidly reoxidized by either oxygen or H2O2. A conformational change of the Type 2 copper was concomitant with the fast reduction of Type 1 copper, whereas its reduction occurred during the slow phase. This sequence of events was reversed in the reoxidation step, that is, the Type 2 copper reappeared rapidly as the species with altered conformation and reverted to the symmetry typical of the native state in the slow phase. The specific reaction of a blue-copper site with the H2O2 can tentatively be related to the established ability of caeruloplasmin to prevent ‘oxidative’ attack of proteins and lipids.

scholarly journals Dependence on freezing of the geometry and redox potential of type 1 and type 2 copper sites of Japanese-lacquer-tree (Rhus vernicifera) laccase

1981 ◽  
Vol 193 (2) ◽  
pp. 639-642 ◽  
Author(s):  
L Morpurgo ◽  
L Calabrese ◽  
A Desideri ◽  
G Rotilio
Keyword(s):  
Redox Potential ◽  
Hyperfine Splitting ◽  
Room Temperature ◽  
Redox Properties ◽  
Blue Copper ◽  
Hyperfine Splitting Constant ◽  
Splitting Constant ◽  
Rhus Vernicifera

The room-temperature e.p.r. spectrum of the Japanese-lacquer-tree (Rhus vernicifera) laccase shows A parallel (the hyperfine splitting constant) and g parallel values of both the Type 1 and Type 2 Cu appreciably different from those measured at liquid-N2 temperature. The geometry of the sites, as inferred from the room-temperature e.p.r. parameters, is more consistent with their redox properties. A rough correlation is found between A parallel and g parallel values and redox potential of the blue copper in several enzymes.

scholarly journals Modulating the copper–sulfur interaction in type 1 blue copper azurin by replacing Cys112 with nonproteinogenic homocysteine

2014 ◽  
Vol 1 (2) ◽  
pp. 153-158 ◽  
Author(s):  
Kevin M. Clark ◽  
Yang Yu ◽  
Wilfred A. van der Donk ◽  
Ninian J. Blackburn ◽  
Yi Lu
Keyword(s):  
Amino Acid ◽  
Blue Copper ◽  
Copper Site ◽  
Type 1 Copper

Replacement of conserved Cys112 in azurin with a nonproteinogenic amino acid homocysteine affords a type-1 copper site with decreased Cu–SCys covalency.

Loop-Directed Mutagenesis of the Blue Copper Protein Amicyanin fromParacoccus versutusand Its Effect on the Structure and the Activity of the Type-1 Copper Site

2000 ◽  
Vol 122 (2) ◽  
pp. 204-211 ◽  
Author(s):  
Christian Buning ◽  
Gerard W. Canters ◽  
Peter Comba ◽  
Christopher Dennison ◽  
Lars Jeuken ◽  
...  
Keyword(s):  
Directed Mutagenesis ◽  
Blue Copper Protein ◽  
Blue Copper ◽  
Copper Protein ◽  
Copper Site ◽  
Type 1 Copper

scholarly journals Low-temperature resonance-Raman spectra of Japanese-lacquer-tree (Rhus vernicifera) laccase, type-2-copper-depleted laccase and H2O2-treated type-2-copper-depleted laccase

1983 ◽  
Vol 213 (2) ◽  
pp. 503-506 ◽  
Author(s):  
G Musci ◽  
A Desideri ◽  
L Morpurgo ◽  
A Garnier-Suillerot ◽  
L Tosi
Keyword(s):  
Raman Spectra ◽  
Strong Dependence ◽  
Resonance Raman ◽  
Local Symmetry ◽  
Structural Rearrangements ◽  
Blue Copper ◽  
Copper Site ◽  
Resonance Raman Spectra ◽  
Rhus Vernicifera

Resonance-Raman spectra of Japanese-lacquer-tree (Rhus vernicifera) laccase, type-2-copper-depleted laccase and the latter form treated with H2O2 were measured in liquid and frozen solution, on excitation into the 600 nm absorption band. Significant changes in intensity and/or frequency of the bands lying in the 370-430 cm-1 region were observed on freezing, indicating local structural rearrangements taking place at the blue copper site. These findings corroborate previous suggestions based on e.p.r. measurements and redox data [Morpurgo, Calabrese, Desideri & Rotilio (1981) Biochem. J. 193, 639-642]. They show the strong dependence of the physical properties of blue copper centres on local symmetry. Some conclusions on the origin of the Raman bands are also drawn.

scholarly journals The Blue Copper-Containing Nitrite Reductase fromAlcaligenes xylosoxidans: Cloning of the nirAGene and Characterization of the Recombinant Enzyme

1999 ◽  
Vol 181 (8) ◽  
pp. 2323-2329 ◽  
Author(s):  
Miguel Prudêncio ◽  
Robert R. Eady ◽  
Gary Sawers
Keyword(s):  
Amino Acid ◽  
Nitrite Reductase ◽  
Recombinant Enzyme ◽  
Leader Peptide ◽  
Resonance Spectroscopy ◽  
Gene Encoding ◽  
Blue Copper

ABSTRACT The nirA gene encoding the blue dissimilatory nitrite reductase from Alcaligenes xylosoxidans has been cloned and sequenced. To our knowledge, this is the first report of the characterization of a gene encoding a blue copper-containing nitrite reductase. The deduced amino acid sequence exhibits a high degree of similarity to other copper-containing nitrite reductases from various bacterial sources. The full-length protein included a 24-amino-acid leader peptide. The nirA gene was overexpressed inEscherichia coli and was shown to be exported to the periplasm. Purification was achieved in a single step, and analysis of the recombinant Nir enzyme revealed that cleavage of the signal peptide occurred at a position identical to that for the native enzyme isolated from A. xylosoxidans. The recombinant Nir isolated directly was blue and trimeric and, on the basis of electron paramagnetic resonance spectroscopy and metal analysis, possessed only type 1 copper centers. This type 2-depleted enzyme preparation also had a low nitrite reductase enzyme activity. Incubation of the periplasmic fraction with copper sulfate prior to purification resulted in the isolation of an enzyme with a full complement of type 1 and type 2 copper centers and a high specific activity. The kinetic properties of the recombinant enzyme were indistinguishable from those of the native nitrite reductase isolated from A. xylosoxidans. This rapid isolation procedure will greatly facilitate genetic and biochemical characterization of both wild-type and mutant derivatives of this protein.

An Axial Met Ligand at a Type 1 Copper Site is Preferable for Fast Electron Transfer

ChemBioChem ◽  
2004 ◽  
Vol 5 (11) ◽  
pp. 1579-1581 ◽  
Author(s):  
Mark D. Harrison ◽  
Christopher Dennison
Keyword(s):  
Electron Transfer ◽  
Fast Electron ◽  
Copper Site ◽  
Type 1 Copper

scholarly journals Defining the Role of the Axial Ligand of the Type 1 Copper Site in Amicyanin by Replacement of Methionine with Leucine

Biochemistry ◽  
2009 ◽  
Vol 48 (39) ◽  
pp. 9174-9184 ◽  
Author(s):  
Moonsung Choi ◽  
Narayanasami Sukumar ◽  
Aimin Liu ◽  
Victor L. Davidson
Keyword(s):  
Axial Ligand ◽  
Copper Site ◽  
Type 1 Copper

Effect of the Methionine Ligand on the Reorganization Energy of the Type-1 Copper Site of Nitrite Reductase

2007 ◽  
Vol 129 (3) ◽  
pp. 519-525 ◽  
Author(s):  
Hein J. Wijma ◽  
Iain MacPherson ◽  
Ole Farver ◽  
Elitza I. Tocheva ◽  
Israel Pecht ◽  
...  
Keyword(s):  
Nitrite Reductase ◽  
Reorganization Energy ◽  
Copper Site ◽  
Type 1 Copper

Spectroscopic and Magnetic Studies of Human Ceruloplasmin:  Identification of a Redox-Inactive Reduced Type 1 Copper Site†

Biochemistry ◽  
1998 ◽  
Vol 37 (26) ◽  
pp. 9570-9578 ◽  
Author(s):  
Timothy E. Machonkin ◽  
Hua H. Zhang ◽  
Britt Hedman ◽  
Keith O. Hodgson ◽  
Edward I. Solomon
Keyword(s):  
Magnetic Studies ◽  
Copper Site ◽  
Type 1 Copper ◽  
Human Ceruloplasmin
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