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1.
The field of medicinal inorganic chemistry is rapidly advancing. In particular organometallic complexes have much potential as therapeutic and diagnostic agents. The carbon‐bound and other ligands allow the thermodynamic and kinetic reactivity of the metal ion to be controlled and also provide a scaffold for functionalization. The establishment of structure–activity relationships and elucidation of the speciation of complexes under conditions relevant to drug testing and formulation are crucial for the further development of promising medicinal applications of organometallic complexes. Specific examples involving the design of ruthenium and osmium arene complexes as anticancer agents are discussed. 相似文献
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Three procedures, matrix matching, plasma optimisation and single-point standard-addition, have been evaluated to ascertain the best procedure for simultaneous multi-element analysis of industrial soils by ICP-AES with CCD detection. A standard reference material, CRM143 from the Bureau Communautaire de Réference (BCR), has been analysed for Cd, Cr, Cu, Mn, Ni and Pb using the three different matrix interference correction procedures. All three procedures give comparable results which are in good agreement with the BCR values, except for Cr. The single-point standard addition procedure was chosen, on the basis of economy and ease of implementation, to correct for matrix interferences in the determination of Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sn and V in soil samples collected from an industrial site in England. Concentrations of some of the elements were found to vary greatly with sampling depth. For example, the concentration of Mn, determined using the atomic line at 279.920 nm, increased from 426 ± 3 g/g at a depth of 18–28 cm to 5996 ± 144 g/g at 60–85 cm. 相似文献
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Alan Rigter Jan PM Langeveld Drophatie Timmers-Parohi Jorg G Jacobs Peter LJM Moonen Alex Bossers 《BMC biochemistry》2007,8(1):6
Background
The common event in transmissible spongiform encephalopathies (TSEs) or prion diseases is the conversion of host-encoded protease sensitive cellular prion protein (PrPC) into strain dependent isoforms of scrapie associated protease resistant isoform (PrPSc) of prion protein (PrP). These processes are determined by similarities as well as strain dependent variations in the PrP structure. Selective self-interaction between PrP molecules is the most probable basis for initiation of these processes, potentially influenced by chaperone molecules, however the mechanisms behind these processes are far from understood. We previously determined that polymorphisms do not affect initial PrPC to PrPSc binding but rather modulate a subsequent step in the conversion process. Determining possible sites of self-interaction could elucidate which amino acid(s) or amino acid sequences contribute to binding and further conversion into other isoforms. To this end, ovine – and bovine PrP peptide-arrays consisting of 15-mer overlapping peptides were probed with recombinant sheep PrPC fused to maltose binding protein (MBP-PrP). 相似文献6.
Liang X Parkinson JA Weishäupl M Gould RO Paisey SJ Park HS Hunter TM Blindauer CA Parsons S Sadler PJ 《Journal of the American Chemical Society》2002,124(31):9105-9112
As platforms for the design of metal-based therapeutic and diagnostic agents, macrocycles are rigid enough to provide strong metal binding sites and orient functional groups stereoselectively, yet flexible enough to accommodate structural changes required for induced-fit recognition of biological targets. We consider the recognition of the Zn(II) complex of the bis-tetraazamacrocycle xylyl-bicyclam, a potent anti-HIV agent, by the coreceptor CXCR4, a G-protein-coupled receptor used by HIV for membrane fusion and cell entry. NMR studies show that the macrocycles of Zn(II)(2)-xylyl-bicyclam perchlorate exist in aqueous solution as two major configurations, trans-I (nitrogen chirality R,S,R,S), and trans-III (S,S,R,R). Acetate addition induced a major structural change. X-ray crystallography shows that the acetate complex contains the unusual cis-V cyclam configuration (R,R,R,R and folded) with bidentate coordination of acetate to Zn(II) plus second-coordination-sphere double H-bond formation between diagonal NH protons on the opposite cyclam face and acetate carboxylate oxygens. Detailed 1D and 2D NMR studies show that the major configuration of Zn(II)(2)-xylyl-bicyclam acetate in aqueous solution is cis-V/trans-I. Molecular modeling shows that an analogous cis-V site can be formed when Zn(II)(2)-xylyl-bicyclam binds to CXCR4, involving the carboxylate groups of Asp262 (Zn(II) coordination) and Glu288 (double H-bonding). The second cyclam can adopt the trans-I (or trans-III) configuration with Zn(II) binding to Asp171. These interactions are consistent with the known structure-activity relationships for bicyclam anti-HIV activity and receptor mutation. Consideration of the anti-HIV activity of xylyl-bicyclam complexes of other metal ions suggests that affinity for carboxylates, configurational flexibility, and kinetic factors may all play roles in receptor recognition. For example, Pd(II) cyclam complexes interact only weakly with axial ligands and are inflexible and inactive, whereas Co(III) cyclams bind carboxylates strongly, are configurationally flexible, and yet have low activity. Our findings should aid the design of new generations of active macrocycles including highly specific chemokine receptor antagonists. 相似文献
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1H and (113)Cd NMR studies are used to investigate the Cd(2+) binding sites on serum albumin (67 kDa) in competition with other metal ions. A wide range of mammalian serum albumins possess two similar strong Cd(2+) binding sites (site A 113-124 ppm; site B 24-28 ppm). The two strong sites are shown not to involve the free thiol at Cys34. Ca(2+) influences the binding of Cd(2+) to isolated human albumin, and similar effects due to endogenous Ca(2+) are observed for intact human blood serum. (1)H NMR studies show that the same two His residues of human serum albumin are perturbed by Zn(2+) and Cd(2+) binding alike. Zn(2+) displaces Cd(2+) from site A which leads to Cd(2+) occupation of a third site (C, 45 ppm). The N-terminus of HSA is not the locus of the two strong Cd(2+) binding sites, in contrast to Cu(2+) and Ni(2+). After saturation of the N-terminal binding site, Cu(2+) or Ni(2+) also displaces Cd(2+) from site A to site C. The effect of pH on Cd(2+) binding is described. A common Cd(2+)/Zn(2+) binding site (site A) involving interdomain His residues is discussed. 相似文献
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Novakova O Kasparkova J Bursova V Hofr C Vojtiskova M Chen H Sadler PJ Brabec V 《Chemistry & biology》2005,12(1):121-129
We analyzed DNA duplexes modified at central guanine residues by monofunctional Ru(II) arene complexes [(eta(6)-arene)Ru(II)(en)(Cl)](+) (arene = tetrahydroanthracene or p-cymene, Ru-THA or Ru-CYM, respectively). These two complexes were chosen as representatives of two different classes of Ru(II) arene compounds for which initial studies revealed different binding modes: one that may involve DNA intercalation (tricyclic-ring Ru-THA) and the other (mono-ring Ru-CYM) that may not. Ru-THA is approximately 20 times more toxic to cancer cells than Ru-CYM. The adducts of Ru-THA and Ru-CYM have contrasting effects on the conformation, thermodynamic stability, and polymerization of DNA in vitro. In addition, the adducts of Ru-CYM are removed from DNA more efficiently than those of Ru-THA. Interestingly, the mammalian nucleotide excision repair system has low efficiency for excision of ruthenium adducts compared to cisplatin intrastrand crosslinks. 相似文献