Mononuclear blue copper proteins

Nersissian AM, Immoos C, Hill MG, Hart PJ, Williams G, Herrmann RG, Valentine JS (1998) Uclacyanins, stellacyanins, and plantacyanins are distinct subfamilies of phytocyanins plant-specific mononuclear blue copper proteins. Protein Sci 7 1915-1929... 

In a beautifiil recent work, the groups of K. Pierloot and B. O. Roos have proposed a fairly complete understanding of the relation between the electronic spectra and the stmcture of the mononuclear copper-cysteinate proteins. This theoretical work is based on DFT geometry optimizations of several blue copper protein models from [Cu(NH3)2(SH)(SH2)+] to... 

Similar sequence alignments also revealed that CcOII shared similar structural homology with the mononuclear type 1 blue copper proteins and the main difference between the two families of proteins resided in the FG loop sequence (Figure The conversion of the blue copper center... 

A structurally based amino-acid sequence alignment strongly suggests a three-domain structure for laccase, closely related to ascorbate oxidase, and a six-domain structure for ceruloplasmin. These domains demonstrate homology with the small blue copper proteins. The relationship suggests that laccase, like ascorbate oxidase, has a mononuclear blue copper in domain 3 and a trinuclear copper between domain 1 and domain 3, and ceruloplasmin has mononuclear copper ions in domains 2, 4, and 6 and a trinuclear copper between domain 1 and domain 6. 

Small blue copper proteins contain a mononuclear copper site with three characteristic properties (1) an intense blue color at approximately 600 nm, with absorption coefficients of 2000-6000 moHMcm due to a S(Cys) Cu(II) charge transfer and (2) an unusually narrow hyperfme coupling (A values of 0.0035-... 

ABSTRACT, The cyclic voltanraietric behaviour of four mononuclear copper(II) complexes and one binuclear copper(I) complex with the ligand 1,6-bis(3,5-dimethyl-l-pyrazolyl)-2,5-dithiahexane (bddh) was studied. Their oxidation-reduction properties will be discussed in terms of the possible relevance of these complexes as models of the Type 1 site of the blue-copper proteins. 

This copper(II) mononuclear complex is responsible for some remarkable properties, one of which is the high redox potentials of the copper(II) ions in these environments. These blue-copper proteins are engaged in electron transport, which involves a switching of the oxidation state of copper between +2 and + ... 

Metalloproteins are convenient systems to study biological ET, and copper-containing enzymes are important among them [23]. Blue copper proteins include mononuclear proteins involved in intermolecular ET such as plastocyanins and azurins as well as multicopper enzymes [23, 24]. These copper centers exhibit an extremely intense Ught absorption band, which is responsible for their deep blue color, and a very small Cu parallel hyperfine spUtting in their electron paramagnetic spectra [25,26. ... 

Copper sites in proteins have traditionally been classified into three classes blue type 1 sites (present in the blue copper proteins), normal type 2 sites (tetragonal mononuclear copper sites), and type 3 (spin-coupled pairs of copper ions). The type 1 sites have been further classified as axial or rhombic depending on their EPR (and other spectroscopic) characteristics." Plastocyanin (axial) and nitrite reductase (rhombic) are typical examples of type 1 proteins. Proteins with properties intermediate between those of type 1 and type 2 sites have been termed type 1.5." ... 

The mononuclear blue (or type 1) copper proteins (cupredoxins) see Copper Proteins with Type 1 Sites), involved in biological electron transport, share a common structural motif, in which the single Cu(ll) ion is tightly bound ( 1.9-2.2 A) to two histidine and one cysteine ligand... 

Type I and 2 mononuclear copper centers in enzymes and proteins are distinguished by theit different EPR spectra for Cu(ll). Type 1 and 2 spectra exhibit comparatively narrowly and widely spaced hyperfine lines, respectively, for the electton-nuclear spin interaction. The more narrow the spacing, the weaker is the interaction. Type 1 cupric centers generally have an intensely blue color, whereas type 2 centets are virtually colotless. 

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