Three generic types of copper centers have been defined based on their electronic and magnetic properties. A tour of blue copper proteins university of toronto. Copperii proteins are amenable for nmr investigations. Active site structures and the redox properties of blue copper proteins. 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.
Interaction of cytochrome c with the blue copper proteins. Analyses of spinach plastocyanin, pseudomonas aeruginosa. Coordination environment and fluoride binding of type 2. These molecules are visualized, downloaded, and analyzed by users who range from students to specialized scientists. Mavicyanin, a blue copper protein from cucurbita pepo medullosa. Active site structures and the redox properties of blue. Pdf role of the surfaceexposed and coppercoordinating. The redox activity as probed by the electron self exchange reaction of the cu centre seems not to be affected. Copper proteins typ i, ii, iii copper elearning chemistry.
A method of classification and recognition of blue copper. Blue copper proteins function as mobile electron carriers in a wide variety of biological systems. These proteins are characterized by a molec ular mass of 1022 kda and an intense absorption band near 600 nm in the oxidized form rydin, 1984. Blue copper azurins have been extensively characterized by means of multiple techniques which include xray diffraction, 3,4 electron paramagnetic resonance 5,6 or nuclear magnetic resonance. A harmful side product of respiration is generated by the one electron. In contrast to the nirs, the classic blue copper sites in plastocyanin and azurin show no temperaturedependent behavior, indicating that a single species is present at all temperatures. Solomons group was particularly successful in unveiling the electronic structure of cu sites in various copper proteins. Synthetic models for active sites of reduced blue copper proteins. On the role of strain in blue copper proteins springerlink. Electronic structures of metal sites in proteins and models. Copper ii bis 1,4,7ttcn is unusually symmetrical evidenced by both solid phase and ambient temperature aqueous phase electron paramagnetic resonance spectra. Blue copper proteins bcps are relatively small soluble copper proteins 7, 14, 15. 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.
We have studied the optimum vacuum geometry of oxidised and reduced copper sites, the relative stability of trigonal and tetragonal cuii structures, the relation between the structure and electronic spectra, the reorganisation energy, and reduction potentials. Plastocyanin and the blue copper proteins springerlink. The blue copper proteins are characterized by very intense optical absorption near 600 m and unusually low cupric hyperfine splitting a. Users can perform simple and advanced searches based on annotations relating to sequence, structure and function. Example for typei blue copper protein are plastocyanine, azurin, and nitrite reductase. Copper proteins are proteins that contain one or more copper ions as prosthetic groups. Auracyanin b, one of two similar blue copper proteins produced by the thermophilic green nonsulfur photosynthetic bacterium chloroflexus aurantiacus, crystallizes in space group p6422 ab115. Thermodynamic equilibrium between blue and green copper. Mononuclear copper centers in proteins may be classified into two classes 9. Mavicyanin, a blue copper protein from cucurbita pepo. The coordination environment of the type 2 nonblue copper in native ascorbate oxidase lascorbate.
The molecule resembles other blue copper proteins in having a greek key betabarrel structure, except that the barrel is open on one side and is better described as a betasandwich or betataco. Blue copper proteins such as plastocyanin pc and azurin az function as electron shuttles in energy conversion systems, although the biological role of blue copper protein classified. Blue copper proteins bcps are relatively small soluble copper proteins. Theoretical investigations of the structure and function of the blue copper proteins are described. The fluorescence spectra of azurin solid line and plastocyanin broken line derivatives. Variation in the chemical nature of the axial ligand 442 5. Colour, magnetic resonance and symmetry of the cupric site in. The blue cu bc or type 1 t1 proteins 1 carry out electron transfer et 25 in a wide variety of biological systems with variable enzymatic architectures. Small blue copper proteins contain a mononuclear copper site with three characteristic properties. From the early days of bioinorganic chemistry researchers were fascinated by the unique spectral features of the bc proteins. All atoms, including hydrogen atoms, are shown in this display. Thermodynamic equilibrium between blue and green copper sites. Our azurin was purified from alcaligenes denitrificans nctc 8582 and crystallized in its oxidized.
The question is addressed in this contribution with reference to the socalled blue copper proteins, each of which has a single copper atom at its active centre. Blue copper proteins, binuclear copper proteins, and multi copper oxidases all have distinct. The blue copper protein induced during growth of thiobacillus versutus on methylamine was purified and characterized. The protein structure of a type 1 blue copper protein, amicyanin, is built off of polypeptide folds that are commonly found in blue copper proteins.
Dec 15, 1988 a simple colorimetric test for the cui content in blue copper proteins is described. Files available from the acs website may be downloaded for personal use only. The blue copper proteins have a beautiful blue colour, far more intense than that of the cuii ion in water, but similar in hue. Blue copper protein precursor pisum sativum garden pea.
In type 1 t1 copper proteins, also called blue copper proteins, the copper is ligated by two histidines and a cysteine, which form the planar trigonal base of a pyramid that is completed by variable distal ligands. The blue copper proteins chosen for the study were plantacyanin. Recent advances in understanding blue copper proteins. This n2s small blue copper proteins 914 kda are a class of donor set is conserved in all members of the blue copper protein mononuclear copper proteins that contain a socalled type1 or family. In type 1 t1 copper proteins, also called blue copper proteins, the copper is ligated by two histidines and a cysteine, which form the planar trigonal base. Methionine ligand interaction in a blue copper protein. From a structural and spectroscopic point of view, the three main types of.
Interaction of cytochrome c with the blue copper proteins, plastocyanin and azurin received for publication, august 3, 1982 mary ann augustin, stephen k. Geoffrey sykes from the department of inorganic chemistry, the university, newcastle upon. Some proteins in blue copper proteins have similar properties. Blue copper proteins bcps are small and generally soluble coppercontaining. From the early days of bioinorganic chemistry researchers were fascinated by the unique spectral features of the bc proteins 1. Their properties have been examined using computercontrolled electrochemical and spectroscopic techniques. Here we use a combination of protein engineering and single molecule force experiments to study the individual unfolding pathways of two model blue copper proteins. 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 blue type 1bindingsite is anessential component of a numberof copper electron transfer proteins, including azurin, stellacyanin, laccase, plastocyanin, ascorbate oxidase. Folding and unfolding in the blue copper protein rusticyanin.
Isolation and characterization of a blue copper protein from. Type i copper centers, typical of blue copper proteins, are characterized by the presence of a metal ion strongly bound to two his and one cys in a distorted trigonal geometry. They contain a type 1 copper i1 ion characterized by an. Stark spectroscopic studies of blue copper proteins. In all cases the binding site is generally conserved. An inducible periplasmic blue copper protein from paracoccus. Comparison oflmuctbandpositionsfor type 1 copper proteins andcobaltii derivatives protein pmax, kk ai, kk coiipl 26. An unusually high redox potential for the copper complex indicates extraordinary stability of the cui oxidation state but evidently not at the expense of cuii stability. Full text full text is available as a scanned copy of the original print version. Methionine ligand interaction in a blue copper protein characterized by siteselective infrared spectroscopy. The crystal structure of the cucumber basic protein cbp, a type 1 or blue copper protein, has been refined at 1. In some cases it is not easy to distinguish the proteins each other. The two most studied are azurin and plastocyanin, which are extracted from bacteria and poplar leaves, respectively. Solomona,2 adepartment of chemistry, stanford university, stanford, ca 94305.
Thermodynamic equilibrium between blue and green copper sites and the role of the protein in controlling function somdatta ghosha,1, xiangjin xiea,1, abhishek deya, yan sunb, charles p. Generally, a linear correlation slope about 1 is found between reduction potential and lmct band position in analogous series of metal complexes 10. Type 1, or blue copper centers the copper is coordinated to at least two imidazole nitrogens from his and one sulfur from cys. A comparative analysis of their molecular interaction properties f.
Caeruloplasmin has several of these functions, and is a blue colour, hence the recently acquired description as a moonlighting protein. Blue copper proteins are involved in respiratory and photosynthetic electron transport. These proteins contain type i copper centers which are characterized by an intense absorption band e 5000 m cm around 600 nm. The spectroscopic and electrochemical properties of blue copper proteins are strikingly different from. Cobalt ii derivatives of blue copper proteins 4761 z 300 320 340 360 nm fig. Blue type 1 copper protein, plastocyanintype ipr001235. Chapter 1 the structure and function of blue copper proteins. The mechanochemistry of copper reports on the directionality.
This research suggests a mechanism by which no could regulate the activity of blue copper proteins involved in denitrification. Nitric oxide no has important functions in all forms of life and. Wade1 1european molecular biology laboratory, postfach 10 2209, meyerhofstrasse 1, 69012 heidelberg, germany 2universita degli studi di modena e reggio emilia, dipartimento di chimica, via campi 183, 41100 modena, italy. Electronic structure and bonding of the blue copper site in. This may not be the complete list of references from this article.
Structures of the protein from poplar, algae, parsley, spinach, and french bean plants have been characterized crystallographically. Several subclasses of the blue copper proteins, such as the amicyanins, azurins, lastocyanins. Colour, magnetic resonance and symmetry of the cupric site. Investigation of the binding of inorganic complexes to blue copper proteins by 1h nmr spectroscopy, i. A method of classification and recognition of blue copper protein.
Abstract the bis 1,4,7trithiacyclononane 1,4,7ttcn complexes of iron, cobalt, nickel and copper are reported in this work. Classification according to substrate specificity laccase ec 1. Stellacyanin is a copper protein belonging to the family of type i or blue copper proteins. Isolation, characterization, and amino acid sequences of.
May 01, 2002 type 1, blue copper proteins constitute a respiratory nitritereducing system in pseudomonas aureofaciens. They have been divided into seven distinct classes rydin, 1988 with the auracyanin blue copper pro teins described in this work appearing to form an. Pdf on sep 1, 1998, mats hm olsson and others published proteins, blue copper. The alkaline transition of blue copper proteins, cucumis sativus. A large amount of experimental data is available on blue copper proteins. Blue copper proteins, a class of type 1 copper proteins, are small proteins containing a cupredoxin fold and a single type i copper ion coordinated by two histidine ndonors, a cysteine thiolate sdonor and a methionine thioether sdonor. Copper proteins with type 1 sites based in part on the.
Paracoccus denitrificans synthesizes a type i blue copper protein which mediates electron transfer be tween methylamine dehydrogenase. Abstract a molecular mechanics force field for blue copper proteins has been developed, based on a rigid potential energy surface scan of the. Isolation and characterization of a blue copper protein. Plastocyanin, a protein having a negative charge of about 7, yields a bimolecular rate constant with native ferrocytochrome c of 1. The study to recognize and classify in blue copper proteins has important roles to recognize the difference of similar properties, for examples, structures and residue sequences in blue copper proteins. Exploring the anticancer potential of the bacterial protein. They are also similar to one another due to the geometry of the copper site of each copper protein. Understanding how the active site structures of blue copper proteins determine their redox properties is the central structurefunction relationship question of this important class of protein, also referred to as cupredoxins. Despite extensive study, a complete understanding of the contribution of the protein to redox activity.
The rcsb pdb also provides a variety of tools and resources. Often considered prototypical electron transfer et proteins, blue copper proteins use the cuiicui redox couple to perform this critical biological function on both an inter protein plastocyanins pc, azurins, stellacyanin, etc. As a member of the wwpdb, the rcsb pdb curates and annotates pdb data according to agreed upon standards. The structure is very similar to plastocyanin and azurin as they also identify as type 1 copper proteins. We here describe both experimental and computational studies of azurin, plastocyanin and stellacyanin designed to define more accurately the geometric structures of the. For these blue copper proteins, the polypeptide matrix.
Electronic structures of metal sites in proteins and. Larger, multidomain proteins that contain type 1 copper in addition to other types of copper centers are not discussed at any length in this article. Ab initio electronic structure calculations of entire blue. Blue synthesis,spectra,andstructures cuin3sr and cuiin3. This last point is still a subject of debate 10, 12. The mechanochemistry of copper reports on the directionality of. For example, in blue copper proteins such as plastocyanin pc, the structure imparts a highly elongated bond between the cu and a methionine met axial ligand to modulate its redox properties. Plastocyanin was the first of the blue copper proteins to be characterised by xray crystallography. A type 1 or blue copper site is sonamed for an intense absorption band near 600 nm. The procedure is based on the formation of a complex between cui and 2,2biquinoline in an acetic acid medium. A blue copper protein from the green thermophilic photosynthetic bacterium,chloroflexus aurantiacus.
The type 1 t1 or blue cu bc proteins are a highly studied group of electron transfer. A new molecular mechanics force field for the oxidized form of blue. Blue synthesis,spectra,andstructures cuin3sr and cuiin3sr. Blue copper proteins are relatively small copper containing proteins.
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