The metal coordination geometry of different blue copper proteins. For example, figure 2 shows how the first c2 domain of synaptotagmin i pdb entry 1rsy, which presented a new calciumbinding fold 7, is firmly anchored in a large structural class that contains betasandwich proteins with topological similarity to immunoglobulinlike domains and blue copper proteins. Copper binding sites, consisting of the side chains of two histidine, one cysteine and one methionine residues, can be. The blue copper proteins owe their name to their intense blue coloration. They serve as electron transfer agents, with the active site shuttling between cui and cuii. In green type1 copper proteins, the cysteinecopper bond elongates and the methioninecopper bond contracts. How the local geometry of the cubinding site determines the.
As indicated by their name, these are coloured proteins, their prosthetic group often contains a metal element fe, cu, mg. Copper proteins are often classified as type i, type ii, or type iii centers, depending on the environment of the metal ion and spectroscopic. The amino acid sequences of two blue copper proteins from the pink facultative methylotroph pseudomonas am1 n. Variation in the chemical nature of the axial ligand 442 5. Archive mmcif file updated mmcif file pdb file pdb header pdb file gz pdbml pdbml atom lines pdbml no atoms structure factors eds map eds difference map assembly composition xml assembly 1 mmcif. Pdb 1aac structure summary protein data bank in europe. Molecular features of copper binding proteins involved in. Small blue copper proteins contain a mononuclear copper site with three characteristic properties. Copper proteins and oxygen journal of general physiology. Plastocyanin was the first of the blue copper proteins to be characterised by xray crystallography. They each consist of a single polypeptide chain and bind one copper atom. Structurefunction analysis of blue copper proteins by.
A good example of this is the enzyme nitrite reductase. Blue dextran molecular weight 2,000,000 sigma prod. The blue copper centres such centres owe their name to the intense blue colouration of the corresponding cuii proteins. Copper in proteins and enzymes linkedin slideshare. Crystal structure of auracyanin, a blue copper protein from. Each subunit houses a type 1 copper site in domain 1 and a type 2type 3 trinuclear copper cluster at the subunitsubunit interface.
Blue copper proteins are typei copper containing redox proteins whose role is to shuttle electrons from an electron donor to an electron acceptor in bacteria and plants. The copper binding sites in a variety of copper containing metalloproteins have unusual spectroscopic and chemical properties which have led to their description as blue copper proteins. Proteins and synthetic models blue copper proteins. In green type1 copper proteins, the cysteine copper bond elongates and the methionine copper bond contracts. It is a product that is helpful in reducing the appearance of fine lines and wrinkles in the area around your eye to make sure that you realize a smooth and youthful skin. The analysis provides a classification of the blue copper proteins and shows that i comparison of the molecular electrostatic potentials provides useful information complementary to that. Structures of the protein from poplar, algae, parsley, spinach, and french bean plants have been characterized crystallographically. This study compares biuret, lowry and bradford methods for measuring hen albumenand egg yolk as protein samples. Copper proteins typ i, ii, iii copper elearning chemistry.
Relation between the structure and spectroscopic properties of. Cox17, cox11 and sco1 proteins for copper delivery to the cu a and cu b of cytochrome c oxidase as shown in the assembly of yeast cco 9, cox 17 is a speci. The affinity of the reactive blue 2 dye in blue dextran for certain proteins has been exploited in protein purification methods. Copperbinding sites, consisting of the side chains of two histidine, one cysteine and one methionine residues, can be. Copper proteins perform a variety of functions in biological systems including uptake, storage and release of electrons. Blue copper oxidase is a trimer, of which each subunit comprises two cupredoxin domains. The role of cytochromes and blue copper proteins in the. Blue copper proteins as bioelements for bioelectronic devices. The use of structural informa tion in the alignment procedure is particularly important for the blue copper protein family, since proteins belonging to different. The blue copper proteins or cupredoxins are a group of proteins that exhibit a number of unusual properties, viz. Blue copper proteins are found in the electron transport chain of prokaryotes and eukaryotes.
Metrical parameters for copper coordination in several representative blue proteins are set out in table 1 2129. Alcaligenes xylosoxidans has been shown to have a blue copper nitrite reductase axnir and two azurins with 67% homology both of which donate electrons to it effectively. The blue copper proteins are small proteins, with type 1 copper center close to the periphery of the protein. The copper site in azurin from alcaligenes denitrificans. Copperbinding proteins are present in the three domains of life 47 and are divided into three classes based on their spectroscopic properties and geometric structure of the active site. Blue copper proteins, binuclear copper proteins, and multicopper oxidases all have distinct epr spectral features relative to normal cupric complexes solomon et al. A structural model of the type 1 copper protein active site. Alcaligenes xylosoxidans has been shown to have a bluecopper nitrite reductase axnir and two azurins with 67% homology both of which donate electrons to it effectively. The first crystal structure of a blue nir axnir in its oxidized and nitritebound forms, with particular emphasis to the cu sites, is presented.
The blue copper protein often called as moonlighting protein, which means a protein can perform more than one function. In blue type1 copper proteins, the cysteinecopper bond is exceptionally small 2. Copper is an essential element in living systems, forming a large number of metalloproteins. Feb 09, 2001 auracyanin b, one of two similar blue copper proteins produced by the thermophilic green nonsulfurphotosynthetic bacterium chloroflexus aurantiacus, crystallizes in space group p 6 4 22 a b 115. Caeruloplasmin has several of these functions, and is a blue colour, hence the recently acquired description as a moonlighting protein. The structure and function of blue copper proteins. Copper proteins are proteins that contain one or more copper ions as prosthetic groups. When bound to a protein the blue dextranprotein complex will be eluted in the void volume of a sephadex gel filtration column. Blue copper type 1 or t1 sites in proteins, which are found in a remarkable variety of organisms ranging from bacteria to humans 1,2, have long fascinated chemists and biologists. Get a printable copy pdf file of the complete article 937k, or click on a page. Structural features and biological functions in blue copper. The role of cytochromes and blue copper proteins in the oxidation of methanol and methylamine in organism 4025, an obligate methylotroph. Structure and function of small blue copper proteins.
The possible presence of sulfhydryl and tyrosine in the copper environment. These methods are commonly used for determination proteins. Complexes of cuii with mixeddonor phenanthrolinecontaining macrocycles. Resonance raman spectroscopy of amicyanin, a blue copper. Chapter 1 the structure and function of blue copper proteins. Aug 14, 20 copper proteins are proteins that contain one or more copper ions as prosthetic groups. Cytochrome c oxidase copper incorporation proteins balatri, e. Ccs is found in the nucleus, cytosol and mitochondrial intermembrane space 7,8.
In blue type1 copper proteins, the cysteine copper bond is exceptionally small 2. Reduction thermodynamics of blue copper proteins molly l. Single t1 cu centers are encountered in small proteins such as plastocyanin and azurin that shuttle electrons between various donors and acceptors. While conversion of the blue copper center with a weak axial ligand to a green copper center containing a medium strength axial ligand has been demonstrated in cupredoxins, converting the blue copper center to a red copper center with a strong axial ligand has not been reported. The electronic spectra of three rhombic type 1 blue copper proteins, nitrite reductase, pseudoazurin, and cucumber basic protein, have been studied by. The first crystal structure of a blue nir axnir in its oxidized and nitritebound forms. Origin, evolution and classification of type3 copper. Auracyanin b, one of two similar blue copper proteins produced by the thermophilic green nonsulfurphotosynthetic bacterium chloroflexus aurantiacus, crystallizes in space group p 6 4 22 a b 115. It is well known that exposure to excess metal impairs the photosynthetic apparatus of. The coordination geometry at the trinuclear copper site is consistent with reduction of the copper ions. Recent advances in understanding blue copper proteins. Blue copper proteins are typei coppercontaining redox proteins whose role is to shuttle electrons from an electron donor to an electron acceptor in bacteria and plants.
Blue copper 5 is a skin care product that is meant to help deal with issues on the areas around your eyes. Preparation and spectroscopic studies of cobaltii derivatives of blue copper proteins. The copper binding sites in a variety of coppercontaining metalloproteins have unusual spectroscopic and chemical properties which have led to their description as blue copper proteins. Electronic structures of metal sites in proteins and. Abstractabsorption, circular dichroism, electron spin resonance and resonance raman spectra of a blue copper protein, plantacyanin from cucumber peel have been measured and these spectral properties compared with those of other blue copper proteins. Copper proteins are often classified as type i, type ii, or type iii centers, depending on the environment of the metal ion and spectroscopic characteristics epr spectrum, color, etc. Effect of carbon growth substrate on the electron transport components of organism 4025 bacteria were grown on methanol or methylamine, membrane and soluble fractions prepared, and cytochromes and blue copper proteins determined as described in methods. Plastocyanin and the blue copper proteins springerlink.
Silver and copper acute effects on membrane proteins and. The prions are manufactured with the prnp gene, and are a misfolded protein, folding prpc to prpsc, the infectious agent. The cupric geometry of blue copper proteins is not strained. Medved department of general and inorganic chemistry, faculty of chemical engineering and technology, university of zagreb, 10 000 zagreb, croatia received 5 may 1997 by unambiguous assignments of maxima in the spectra of copper proteins, the constituent ions in.
Journal of general microbiology 1983, 1, 216521 71. Within the class most information is available for plastocyanin, a component of photosynthetic electron transport, which has proved to be a particular focus of recent research. The colour is particularly distinctive since the metal centres are so optically diluted in these metalloenzymes that only intense absorption in the visible region, resulting from symmetry allowed electronic transitions. The structure was solved usingmultiple wavelength anomalous dispersion data recorded about the cu k absorption edge, and was refined at1. Inner and outersphere metal coordination in blue copper. Blue copper proteins, binuclear copper proteins, and multi copper oxidases all have distinct epr spectral features relative to normal cupric complexes solomon et al.
The structures of the two blue copper proteins, azurin and plastocyanin, provide an opportunity to do just that. Functionally specified protein signatures distinctive for each of the. Its active site can be either an iron haem center or a type i copper complex. The blue copper proteins have a beautiful blue colour, far more intense than that of the cuii ion in water, but similar in hue.
We, as observers, must try and sort out which of those details are relevant to the function, and which to its history or its relatedness to other structures. A large amount of experimental data is available on blue copper proteins. Transforming a blue copper into a red copper protein. Resonance raman spectra of blue copper proteins and the nature of their copper sites. Amicyanin contains 99 and pseudoazurin 123 residues.
The origin of their blue color and the structure of copper complexes and copper proteins are related to the oxidation state of copper ion and relevant electronic transitions probably arising from the formation of charge transfer complexes. If the inline pdf is not rendering correctly, you can download the pdf file here. Further perspectives on the charge transfer transitions of. B xband epr spectra of blue cu top and normal cu bottom. For example, figure 2 shows how the first c2 domain of synaptotagmin i pdb entry 1rsy, which presented a new calciumbinding fold 7, is firmly anchored in a large structural class that contains betasandwich proteins with topological similarity to. Based on structural work, the type 1 copper proteins, azurin. This allows the bound protein to be easily separated from other. Cucomplexes with scorpionate ligands as models for the. Homology relationships among the small blue proteins.
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