Protein-metal interaction

Chiral Chromatography. Chiral chromatography is used for the analysis of enantiomers, most useful for separations of pharmaceuticals and biochemical compounds (see Biopolymers, analytical techniques). There are several types of chiral stationary phases those that use attractive interactions, metal ligands, inclusion complexes, and protein complexes. The separation of optical isomers has important ramifications, especially in biochemistry and pharmaceutical chemistry, where one form of a compound may be bioactive and the other inactive, inhibitory, or toxic. 

Capture array involves the immobilization of non-protein molecules onto the surface which can interact with proteins in the solute phase. Generally, capture molecules may be broad capture agents based on chromatography type surface chemistries such as ion exchange, hydrophobic and metal affinity functionality, or they may be highly specific such as molecular imprinted polymers or oligonucleotide aptamers. 

In earlier studies the in vitro transition metal-catalyzed oxidation of proteins and the interaction of proteins with free radicals have been studied. In 1983, Levine [1] showed that the oxidative inactivation of enzymes and the oxidative modification of proteins resulted in the formation of protein carbonyl derivatives. These derivatives easily react with dinitrophenyl-hydrazine (DNPH) to form protein hydrazones, which were used for the detection of protein carbonyl content. Using this method and spin-trapping with PBN, it has been demonstrated [2,3] that protein oxidation and inactivation of glutamine synthetase (a key enzyme in the regulation of amino acid metabolism and the brain L-glutamate and y-aminobutyric acid levels) were sharply enhanced during ischemia- and reperfusion-induced injury in gerbil brain. 

Proteins are water-soluble biopolymers with a huge number of potential donor atoms and coordination sites which could make them useful carriers of metal complex catalysts. Indeed, a few successful attempts can be found in the literature [139] but often the interaction of proteins and metal complexes lead to a loss of catalytic activity [140]. This was not the case with human serum albumin (HSA) which formed a stable and active catalytically active complex with [Rh(acac)(CO)2]. In the hydroformylation of 1-octene and styrene the selectivity towards aldehydes was excellent, moreover styrene reacted with high regioselectivity (b/1 = 19). The activity... 

Freeman, H. C., and Golomb, M. L. (1970). Model compounds for metal-protein interaction Crystal structure of three platinum(Il) complexes of l- and DL-methionine and glycyl-L-methionine. Chem. Commun. pp. 1523-1524. 

This volume of Advances in Protein Chemistry is the first in which all articles address a single specialized theme within protein science—metal-protein interactions from a structural perspective. Future volumes of Advances in Protein Chemistry will include other thematic volumes in which the reviews will cover different aspects of a single broad area and, as in the past, collections of reviews on a variety of major topics. 

The first article in this volume, by Jenny P. dusker, treats general aspects of metal liganding to functional groups in proteins. This article presents a detailed summary of the geometry of interaction of metals with the various chemical groups of proteins. It also presents, in Sections I through VIII, a lucid development of the principles and terminology of the field of metal-protein interactions. It is with these sections that the newcomer to the field of metalloproteins should start. 

In order to understand the interactions of proteins with metals, it is necessary to consider the effect of pH on the stability of metal chelates.78,78 The following, simplified treatment illustrates the equilibria that can occur between a metal ion, a chelating agent (or other ligand), and hydrogen ion. Although it is almost impossible to apply the equations quantitatively to metalloenzymes, they do illustrate the interactions of the different variables. 

The kinetics of oxidation and reduction of [4Fe-4S] proteins by transition metal complexes and by other electron-transfer proteins have been studied. These reactions do not correlate with their redox potentials.782 The charge on the cluster is distributed on the surface of HiPIP through the hydrogen bond network, and so affects the electrostatic interaction between protein and redox agents such as ferricyanide, Co111 and Mnin complexes.782 783 In some cases, limiting kinetics were observed, showing the presence of association prior to electron transfer.783... 

In these compounds the cobalt atom is enclosed in a highly conjugated cobalamin structure and linked to an alkyl group via a metal-carbon bond. The B12 coenzymes are diamagnetic and can be regarded as complexes of cobalt(III) with a carbanion as a ligand (2). As this review will be limited to cases of direct metal-protein interactions the corrinoids will not be discussed further. 

In general, species containing transition metals and metalloids such as As, Sb, Se and Sn are thermodynamically more stable than those of the alkali and alkaline earth metals. Transition metals and metalloids form an integral part and are linked to the organic constituents by covalent bonds. In contrast alkali and alkaline earth metals are attached loosely by predominantly ionic bonds. Readers interested in the fundamentals of metal-protein interactions are referred to books... 

Chasteen, N.D. 1995. Vanadium-protein interactions. Metal Ions in Biological Systems 31 231-247. 

This type of affinity separation is also known under the name of immobilized metal affinity chromatography (IMAC) and is based on the ion-mediated interaction with proteins. Metal ions are adsorbed first on a chelating... 

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