Peptide deformylase (PDF) is a prokaryotic enzyme that catalyzes the deformylation of nascent peptides generated during protein synthesis and water molecules play a key role in these hydrolases. Using X-ray absorption near edge spectroscopy (XANES) and ab initio calculations we accurately probe the local atomic environment of the metal ion binding in the active site of PDF at different pH value...

Significant cleavage by hammerhead ribozymes requires activation by divalent metal ions. Several models have been proposed to account for the influence of metal ions on hammerhead activity. A number of recent papers have presented data that have been interpreted as supporting a one-metal-hydroxide-ion mechanism. In addition, a solvent deuterium isotope effect has been taken as evidence against ...

We report the 3.4 angstrom crystal structure of a catalytically active group I intron splicing intermediate containing the complete intron, both exons, the scissile phosphate, and all of the functional groups implicated in catalytic metal ion coordination, including the 2'-OH of the terminal guanosine. This structure suggests that, like protein phosphoryltransferases, an RNA phosphoryltransfera...

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...

Molecular imprinting techniques have reached tremendous importance in the research of new artificial recognition systems. The investigation reports the preparation of Cu (II) ion selective polymer with high specificity and selectivity by molecular imprinting approach. For this 4-vinyl pyridine was chosen as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the crosslinking ag...

Metal ions play a functional role in numerous biochemical processes and cellular pathways. Indeed, about 40% of all enzymes of known 3D structure require a metal ion to be able to perform catalysis. The interactions of the metals with the macromolecular framework determine their chemical properties and reactivity. The relevant interactions involve both the coordination sphere of the metal ion a...

We have demonstrated that using a transition metal ion to partially substitute Cu ion of the YSr2Cu3Oy can stabilize its crystal structure and retain superconductivity. The superconducting transition temperature in YSr2(Cu1-xMx)3Oy, where M is transition metal ion, ranges from 40K to 80K depending on the specific M ion. Lattice contraction due to Sr substitution makes the Ba/Sr ion to move clos...

Different alkali metal atoms are observed to donate electrons to CF(3)Br molecules that are oriented in space. For collision energies high enough to overcome the Coulomb attraction, a positive ion/negative ion pair is observed and mass-analyzed using coincident time-of-flight mass spectroscopy. The alkali metal cation and various negative ions are observed. The most abundant negative ion is the...

Galactosyltransferase, which functions as the catalytic component of lactose synthase and in the glycosylation of glycoproteins, has been previously reported to have an absolute dependence on Mn*+ for activity, with a Kd for Mn2+ (lOmS M) 2 to 3 orders of magnitude greater than the physiological range of Mn*+ concentrations (Y 10e6 M). Reinvestigation of the metal ion dependence of this enzyme ...