Nano-electrospray ionization time-of-flight mass spectrometry (ESI-MS) was used to study the conformational consequences of metal ion binding to the colicin E9 endonuclease (E9 DNase) by taking advantage of the unique capability of ESI-MS to allow simultaneous assessment of conformational heterogeneity and metal ion binding. Alterations of charge state distributions on metal ion binding/release...

First, Schiff base iminopyridine ligands has been prepared by the condensation between primaryamines, different substituted anilines and active carbonyl group of pyridine carboxaldehyde, thenthe complexes [diiodo (3-ethylphenyl) pyridine-2-yl methylene amine] mercury(II), complex a,[dibromo (2,5-dimethylphenyl) pyridine-2-yl methylene amine] mercury(II) complex b, and[dinitrato bis-(2,6-dimethy...

The complexation reactions between Cu2+, Pd2+ and Ni2+ metal ions with promethazine (PM) in water or DMF were studied by the spectrophotometric methods at [(15, 25,35 and 45±0.1) °C]. The complexation process was optimized in terms of pH, temperature and contact time. The stoichiometry of the complex was found to be 1:1 (metal ion/ligand). The formation constants of the resulting complexes were...

The intermolecular (outer sphere, OS) interaction of a reducing and an oxidizing metal complex generates a new optical transition involving charge transfer (CT) from the electron donor to the acceptor. OS C T transitions are classified according to the redox site (metal or ligand). Generally, the interaction between donor and acceptor is facilitated by ion pairs consisting of an oxidizing compl...

the complexation reactions between cu2+, pd2+ and ni2+ metal ions with promethazine (pm) in water or dmf were studied by the spectrophotometric methods at [(15, 25,35 and 45±0.1) °c]. the complexation process was optimized in terms of ph, temperature and contact time. the stoichiometry of the complex was found to be 1:1 (metal ion/ligand). the formation constants of the resulting complexes were...

In two-metal catalysis, metal ion A has been proposed to activate the nucleophile and metal ion B to stabilize the transition state. We recently reported crystal structures of RNase H-RNA/DNA substrate complexes obtained at 1.5-2.2 Angstroms. We have now determined and report here structures of reaction intermediate and product complexes of RNase H at 1.65-1.85 Angstroms. The movement of the tw...

A classification of kinetics of metalloporphyrin formation is presented according to the composition of the activated complex involved in the reaction. In the reaction of large metal ions, such as mercury(II) and cadmium(II) with porphyrins, these metal ions can not fit into the porphyrin nucleus and they are out—of-plane in the metalloporphyrin. In this case the reaction is relatively fast and...

synthesis and cation selectivity of 25, 27, dipropoxy-26, 28, di-propoxy 5, 11, 17, 23, ptert-butyl calix[4]arene are studied in acetonitrile solution. the stability constants of differentcomplexes of calixarene (as a ligand) with alkali metal cations are determined at 25 °c by usingspectrophotometric technique.on the basis of calculations, complexation of calixarene with cs+and li+ are more fa...

Phosphatidylcholine vesicles harboring the lipophilic metal ion carrier A23187 in the bilayer and encapsulating ethylenediamine tetraacetic acid (EDTA) exhibit broadly varied, pH-dependent affinity for Cu2+, Pb2+, Cd2+, and Ca2+ at micromolar levels. Initial rates of uptake by these metal-sorbing vesicles (MSVs) is strongly dependent on the metal ion affinity of A23187 and the dissociation rate...

Citrate uptake in Bacillus subtilis is stimulated by a wide range of divalent metal ions. The metal ions were separated into two groups based on the expression pattern of the uptake system. The two groups correlated with the metal ion specificity of two homologous B. subtilis secondary citrate transporters, CitM and CitH, upon expression in Escherichia coli. CitM transported citrate in complex ...