Determination,by inductively coupled plasma mass spectrometry,of changes in cellular metal content resulting from herpes simplex virus-1 (HSV-1) infection

Metals and metal-containing compounds are known to play important roles in many biological processes, including metabolic and detoxification pathways and the formation and function of proteins. Like all organisms, viruses are expected to contain different metals. These metals, either by themselves or in the form of metalloproteins, may be involved in the virus’s ability to infect healthy cells and replicate within them. Identification and speciation of metals in control cells and in cells affected by a virus could be helpful in elucidating infection and replication mechanisms; these might, in turn, be vital to the development of more effective treatments. There has, however, been no extensive investigation of the metals specific viruses contain or affect. The objective of this study was to investigate changes in cellular metal content resulting from herpes simplex virus 1 (HSV-1) infection. Inductively coupled plasma mass spectrometry was used to identify differences between metal concentrations in uninfected and HSV-1-infected mammalian cells. Although it can be assumed that decreases in metal content are a result of cellular response to the virus, increases can be attributed either to cellular response or to the HSV-1 virus itself. Microwave digestion and flow injection methods suitable for small sample volumes were used, and the effects of different virus inactivation procedures were explored. This work is the first step in the identification of metals pertinent to HSV-1 infection and lays the foundation for future studies concentrating on characterization of these metal-associated or containing molecules.     

金属组学：研究生命体系中金属离子的前沿交叉学科

金属组学是一门新兴的前沿交叉学科,是对若干涉及金属相关生命过程的分子机制以及对细胞与组织内全部金属离子和金属配合物进行综合研究的学科．在金属组学中,生命体系中所有的金属蛋白质、金属酶以及其他含金属的生物分子统称为金属组,这个概念与基因组学中的基因组和蛋白质组学中的蛋白质组相类似．本文对金属组学中涉及的若干概念进行阐述,并将着重介绍金属组学中的研究技术和方法,特别是“组和技术”,即把一种高分辨率分离技术如凝胶电泳／激光切除、色谱或者毛细管电泳与一项高灵敏度检测方法,如电感耦合等离子体质谱、电喷雾电离质谱、基质辅助激光解吸附质谱或者X射线荧光／吸收光谱联合起来．并重点分析了这些方法的优缺点以及在分离鉴别金属蛋白、磷酸化蛋白以及硒蛋白、确定金属蛋白的结构与功能的关系和医药中的金属药物活性抗药性方面的研究中的应用．     

Visualising mouse neuroanatomy and function by metal distribution using laser ablation-inductively coupled plasma-mass spectrometry imaging

Metals have a number of important roles within the brain. We used laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to map the three-dimensional concentrations and distributions of transition metals, in particular iron (Fe), copper (Cu) and zinc (Zn) within the murine brain. LA-ICP-MS is one of the leading analytical tools for measuring metals in tissue samples. Here, we present a complete data reduction protocol for measuring metals in biological samples, including the application of a pyramidal voxel registration technique to reproducibly align tissue sections. We used gold (Au) nanoparticle and ytterbium (Yb)-tagged tyrosine hydroxylase antibodies to assess the co-localisation of Fe and dopamine throughout the entire mouse brain. We also examined the natural clustering of metal concentrations within the murine brain to elucidate areas of similar composition. This clustering technique uses a mathematical approach to identify multiple ‘elemental clusters’, avoiding user bias and showing that metal composition follows a hierarchical organisation of neuroanatomical structures. This work provides new insight into the distinct compartmentalisation of metals in the brain, and presents new avenues of exploration with regard to region-specific, metal-associated neurodegeneration observed in several chronic neurodegenerative diseases.     

Metalloallostery and Transition Metal Signaling: Bioinorganic Copper Chemistry Beyond Active Sites

Transition metal chemistry is essential to life, where metal binding to DNA, RNA, and proteins underpins all facets of the central dogma of biology. In this context, metals in proteins are typically studied as static active site cofactors. However, the emergence of transition metal signaling, where mobile metal pools can transiently bind to biological targets beyond active sites, is expanding this conventional view of bioinorganic chemistry. This Minireview focuses on the concept of metalloallostery, using copper as a canonical example of how metals can regulate protein function by binding to remote allosteric sites (e.g., exosites). We summarize advances in and prospects for the field, including imaging dynamic transition metal signaling pools, allosteric inhibition or activation of protein targets by metal binding, and metal-dependent signaling pathways that underlie nutrient vulnerabilities in diseases spanning obesity, fatty liver disease, cancer, and neurodegeneration.     

Identification,characterization and determination of metal-binding proteins by liquid chromatography. A review

The use of liquid chromatography in the separation and determination of metal-binding proteins is reviewed. Advantages and drawbacks of different chromatographic techniques based on various principles: size exclusion, ion exchange (cationic and ionic), reversed phase and affinity, are presented and discussed. The topic "metal-binding proteins" is considered and presented from two different points of view. The first one regards metal speciation in biological samples (serum and blood). In metal speciation studies, the exact identity of the protein to which the metal is bound often remains unknown. The second point of view is that, frequently, the interest of analyzing metal-binding proteins is not related anymore to the metallic fraction of the protein, but to other chemical structures attached to the protein, such as carbohydrates, which indirectly determine how good the function of the protein is. In this review, special attention is paid to studies dealing with the glycosylation of transferrin, and with the glycated isoform of haemoglobin.     

Binding site residues in β-lactamases: role in non-classical interactions and metal binding

Proteins bind with one or more metal ions in their native state to facilitate the biological function of the protein. The study of critical interactions between the biological molecules and metals is an important field of study. In this work, we focus on the functional specificity of residues coordinating with the metals commonly found in β-lactamases, Zn, Mg, Na, Cu, Mn, Ni, Fe, K, and Cd through non-classical interactions. All the residues located in the metal-binding site of β-lactamases are involved in non-classical interactions. The data obtained from this study will be useful to understand the functional role of metal-coordinating residues in the specificity of β-lactamases, thus offering promising strategy to design effective β-lactamase inhibitors.     

Metallomics: An integrated biometal science

Metallomics is an emerging scientific area integrating the research fields related to the understanding of the molecular mechanisms of metal-associated life processes and the entirety of metal and metalloid species within a cell or tissue type. In metallomics, metalloproteins, metalloenzymes and other metal-containing biomolecules in a biological system are referred to as metallomes, similar to genomes and proteomes in genomics and proteomics, respectively. This review discusses the concept of metallomics with a focus on analytical techniques and methods, particularly the so-called hyphenated techniques which combine a high-resolution separation technique (gel electrophoresis/laser ablation, chromatography or capillary electrophoresis) with a highly sensitive detection method such as elemental (inductively coupled plasma, ICP) or molecular (electron spray ionization (ESI) or matrix-assisted laser desorption/ionization (MALDI)) mass spectrometry, or nuclear X-ray fluorescence/absorption spectrometry. The applications of these advanced analytical methods in the identification of metallo-/phospho-/seleno-proteins, probing of relationships between structure and function of metalloproteins, and study of clinically used metallodrugs will be selectively outlined, along with their advantages and limitations.     

Protein fractionation and detection for metalloproteomics: challenges and approaches

At least one third of all proteins are thought to require a metal ion co-factor for their function. Recognition of the importance of metals in biological systems and major advances in analytical instrumentation and technology have led to the emergence of the new research area of metalloproteomics in recent years. Despite this progress, the experimental determination of in-vivo metal cofactors has remained challenging, because this requires elucidation of protein interactions with non-covalently bound metal ions. This critical review highlights current methodological approaches, focusing, in particular, on issues relating to the fractionation and separation of the metalloproteome, including recent experience with metalloproteomics for marine cyanobacteria in our laboratory. Metalloproteomics promises to deliver novel insights into fundamental biological processes in the future, but it is clear that further methodological advances are necessary to exploit the full potential of this emerging research area.     

Heavy-metal remediation by a fungus as a means of production of lead and cadmium carbonate crystals

We show here that reaction of the fungus, Fusarium oxysporum, with the aqueous heavy-metal ions Pb2+ and Cd2+ results in the one-step formation of the corresponding metal carbonates. The metal carbonates are formed by reaction of the heavy-metal ions with CO2 produced by the fungus during metabolism and thus provide a completely biological method for production of crystals of metal carbonates. The PbCO3 and CdCO3 crystals thus produced have interesting morphologies that are shown to arise because of interaction of the growing crystals with specific proteins secreted by the fungus during reaction. An additional advantage of this approach is that the reaction leads to detoxification of the aqueous solution and could have immense potential for bioremediation of heavy metals. Under conditions of this study, the metal ions are not toxic to the fungus, which readily grows after exposure to the metal ions.     

Hard-wall potential function for transport properties of alkali metal vapors

This study demonstrates that the transport properties of alkali metals are determined principally by the repulsive wall of the pair interaction potential function. The (hard-wall) Lennard-Jones (LJ) (15-6) effective pair potential function is used to calculate the transport collision integrals. Accordingly, reduced collision integrals of K, Rb, and Cs metal vapors are obtained from the Chapman-Enskog solution of the Boltzmann equation. The law of corresponding states based on the experimental transport reduced collision integral is used to verify the validity of a LJ(15-6) hybrid potential in describing the transport properties. LJ(8.5-4) potential function and a simple thermodynamic argument with the input PVT data of liquid metals provide the required molecular potential parameters. Values of the predicted viscosity of monatomic alkali metal vapor are in agreement with typical experimental data with average absolute deviations of 2.97% for K in the range of 700-1500 K, 1.69% for Rb, and 1.75% for Cs in the range of 700-2000 K. In the same way, the values of predicted thermal conductivity are in agreement with experiment within 2.78%, 3.25%, and 3.63% for K, Rb, and Cs, respectively. The LJ(15-6) hybrid potential with a hard-wall repulsion character conclusively predicts the best transport properties of the three alkali metal vapors.     

Analysis of the metal-binding selectivity of the metallochaperone CopZ from Enterococcus hirae by electrospray ionization mass spectrometry

Metallochaperones are soluble proteins involved in metal transport and regulation in vivo. Copper metallochaperones belong to a structural family of metal binding domains displaying a ferredoxin-like fold (betaalphabetabetaalphabeta) and a consensus metal-binding motif MXCXXC. The metal-binding selectivities for this class of proteins are poorly documented so far. The present study focuses on the measurement of the selectivity of the copper metallochaperone CopZ from Enterococcus hirae for different metal ions using an experimental approach based on electrospray ionization mass spectrometry (ESI-MS). All the metal cations tested, i.e. Cu(I), Cu(II), Hg(II), Cd(II) and Co(II), form specific metal complexes with CopZ. The study of a chemically modified CopZ as well as variants of CopZ in the active site demonstrated that the complexes observed by ESI-MS, i.e. in the gas phase, corresponded to the complexes previously observed by other analytical methods in solution. Competition experiments allowed the classification of the metal ions by increasing affinities for CopZ as follows: Co < Cd < Hg < Cu. A dissociation constant in the range of 20 microM was determined for cobalt. The affinity of CopZ for the other metals tested was found to be higher, with dissociation constants smaller than micromolar.     

Nascent Proteomics: Chemical Tools for Monitoring Newly Synthesized Proteins

Cellular proteins are dynamically regulated in response to environmental stimuli. Conventional proteomics compares the entire proteome in different cellular states to identify differentially expressed proteins, which suffers from limited sensitivity for analyzing acute and subtle changes. To address this challenge, nascent proteomics has been developed, which selectively analyzes the newly synthesized proteins, thus offering a more sensitive and timely insight into the dynamic changes of the proteome. In this Minireview, we discuss recent advancements in nascent proteomics, with an emphasis on methodological developments. Also, we delve into the current challenges and provide an outlook on the future prospects of this exciting field.     

Analysis of metal-induced oxidative DNA damage in cultured mammalian cells

Reactive oxygen species are continuously generated during oxygen metabolism, and a measurable amount of oxidative DNA damage exists in aerobic organisms. By the determination of Fpg-sensitive sites in mammalian cells in culture, we assessed the background level of oxidative DNA damage and its potential increase by extracellularly applied complexes of iron(III). In V79 Chinese hamster cells the endogenous level of Fpg-sensitive modifications is detectable, but the extent is much lower as compared with results derived from other analytical methods. In V79 cells, the frequency of Fpg-sensitive modifications is considerably enhanced by Fe-NTA in a time- and dose-dependent manner, while no increase is observed after treatment with Fe-citrate. These results indicate that the ability of transition metals to generate oxidative DNA damage in intact cells strongly depends on factors like uptake and intracellular distribution, which will affect the intracellular availability of redox-active metal ions close to critical targets.     

Analysis of metal-induced oxidative DNA damage in cultured mammalian cells

Reactive oxygen species are continuously generated during oxygen metabolism, and a measurable amount of oxidative DNA damage exists in aerobic organisms. By the determination of Fpg-sensitive sites in mammalian cells in culture, we assessed the background level of oxidative DNA damage and its potential increase by extracellularly applied complexes of iron(III). In V79 Chinese hamster cells the endogenous level of Fpg-sensitive modifications is detectable, but the extent is much lower as compared with results derived from other analytical methods. In V79 cells, the frequency of Fpg-sensitive modifications is considerably enhanced by Fe-NTA in a time- and dose-dependent manner, while no increase is observed after treatment with Fe-citrate. These results indicate that the ability of transition metals to generate oxidative DNA damage in intact cells strongly depends on factors like uptake and intracellular distribution, which will affect the intracellular availability of redox-active metal ions close to critical targets.     

Fractionation and identification of metalloproteins from a marine cyanobacterium

Trace metals are essential for the growth of marine cyanobacteria, being required for key cellular processes such as photosynthesis and respiration. Despite this, the metalloproteomes of marine cyanobacteria are at present only poorly defined. In this study, we have probed the major cobalt, iron, manganese, and nickel-binding proteins in the marine cyanobacterium Synechococcus sp. WH8102 by using two different fractionation approaches combined with peptide mass fingerprinting. For the identification of intact metalloproteins, multidimensional native chromatography was used to fractionate the proteome, followed by inorganic mass spectrometry to identify metal-enriched fractions. This approach led to the detection of nickel superoxide dismutase together with its predicted cofactor. We also explored the utility of immobilized metal affinity chromatography (IMAC) to isolate subpopulations of proteins that display affinity for a particular metal ion. We conclude that low-resolution 2D liquid chromatography is a viable fractionation technique to correlate relatively low-abundance metal ions with their few cellular destinations (e.g. Ni), but challenges remain for more abundant metals with multiple destinations such as iron. IMAC has been shown as a useful pre-fractionation technique to screen for proteins with metal-binding capacity, and may become a particularly valuable tool for the identification of metal-trafficking proteins.     

Determination of metal species in biological samples: From speciation analysis to metallomics

The paper makes an attempt to give a definition to metallomics, a branch of science, which actively evolves in the recent years abroad, taking into account such common and well accepted terms as proteomics, genomics, and metabolomics. The author critically revises the analytical methodology that makes possible the detection and identification of individual metal species, the determination of their concentrations and, therefore, distribution in specific biological samples, and also investigates important biological processes involving metals and predicts their biological functions.     

d^0过渡金属化合物对氧气反应性：合成和反应机理研究

众所周知,过渡金属如卟啉中的铁与氧气的结合和反应对许多生物功能和催化氧化至关重要．在这些反应中,过渡金属一般含d价电子,并且金属被氧化往往是其中一个重要的反应步骤．近年来,氧气与d^0过渡金属化合物如Hf（NR2）4（R=烷基）的反应被广泛用来制备金属氧化物薄膜以作为新型微电子器件中的栅（门）绝缘材料．这篇专题文章讨论我们近期对这些反应以及TiO2薄膜形成的研究．在许多氧气与d^0过渡金属化合物的反应中,总是金属被氧化．然而,在d^0过渡金属化合物如Hf（NMe2）4和Ta（NMe2）4（SiR3）与氧气的反应中通常是配体被氧化．如-NMe2和--SIR3配体分别形成了-0NMe2和--OSiR3配体．反应机理和理论方面的研究显示了微电子金属氧化物薄膜形成的途径．     

Metal-binding thermodynamics of the histidine-rich sequence from the metal-transport protein IRT1 of Arabidopsis thaliana

The widespread ZIP family of transmembrane metal-transporting proteins is characterized by a large intracellular loop that contains a histidine-rich sequence whose biological role is unknown. To provide a chemical basis for this role, we prepared and studied a peptide corresponding to this sequence from the first iron-regulated transporter (IRT1) of Arabidopsis thaliana, which transports Fe2+ as well as Mn2+, Co2+, Zn2+, and Cd2+. Isothermal titration calorimetry (ITC) measurements, which required novel experiments and data analysis, and supporting spectroscopic methods were used to quantify IRT1's metal-binding affinity and associated thermodynamics. The peptide, PHGHGHGHGP, binds metal ions with 1:1 stoichiometry and stabilities that are consistent with the Irving-Williams series. Comparison of the metal-binding thermodynamics of the peptide with those of trien provides new insight about enthalpic and entropic contributions to the stability of the metal-peptide complex. Although Fe2+ and other IRT1-transported metal ions do not bind very tightly, this His-rich sequence has a very high entropy-driven affinity for Fe3+, which may have biological significance.     

Applications of luminescent inorganic and organometallic transition metal complexes as biomolecular and cellular probes

The rich photophysical properties of luminescent inorganic and organometallic transition metal complexes, such as their intense, long-lived, and environment-sensitive emission, render them excellent candidates for biological and cellular studies. In this Perspective, we review examples of biological probes derived from luminescent transition metal complexes with a d(6), d(8), or d(10) metal center. The design of luminescent covalent labels and noncovalent probes for protein molecules is discussed. Additionally, the recent applications of these complexes as cellular probes and bioimaging reagents are described. Emphasis is put on the structural features, photophysical behavior, biomolecular interactions, cellular uptake, and intracellular localization properties of luminescent transition metal complexes.     

Adventures with substances containing metals in negative oxidation states

A brief history of substances containing s,p- and d-block metals in negative oxidation states is described. A classification of these species and discussions of formal oxidation state assignments for low-valent transition metals in complexes are included, along with comments on the innocent and noninnocent character of ligands in metalates. Syntheses of highly reduced carbonyl complexes formally containing transition metals in their lowest known oxidation states of III- and IV- are discussed. Atmospheric-pressure syntheses of early-transition-metal carbonyls involving alkali-metal polyarene-mediated reductions of non-carbonyl precursors have been developed. In the absence of carbon monoxide, these reactions afford homoleptic polyarenemetalates, including the initial species containing three aromatic hydrocarbons bound to one metal. In several instances, these metalates function as useful synthons for "naked" spin-paired atomic anions of transition metals.