Search results for "clam"

Sequence-specific and DNA structure-dependent interactions of Escherichia coli MutS and human p53 with DNA

2013

Many proteins involved in DNA repair systems interact with DNA that has structure altered from the typical B-form helix. Using magnetic beads to immobilize DNAs containing various types of structures, we evaluated the in vitro binding activities of two well-characterized DNA repair proteins, Escherichia coli MutS and human p53. E. coli MutS bound to double-stranded DNAs, with higher affinity for a G/T mismatch compared to a G/A mismatch and highest affinity for larger non-B-DNA structures. E. coli MutS bound best to DNA between pH 6 and 9. Experiments discriminated between modes of p53-DNA binding, and increasing ionic strength reduced p53 binding to nonspecific double-stranded DNA, but had…

Coordination Chemistry in the Solid: Evidence for Coordination Modes within Hybrid Materials Different from those in Solution

2002

Two routes of incorporation of europium(III) salts into cyclam-containing hybrid materials have been explored, to elucidate the coordination mode of EuIII in cyclam-containing hybrid materials in a study of the arrangement of cyclam moieties during the solgel process. They were 1) complexation of europium salts by N-tetrasubstituted 1,4,8,11-tetraazacyclotetradecane (cyclam) derivatives bearing four hydrolysable Si(OEt)3 groups, followed by hydrolysis and polycondensation of these complexes; and 2) hydrolysis and polycondensation of N-tetrasubstituted silylated cyclam derivatives, then incorporation of europium salts directly into the hybrid materials. The coordination mode of europium salt…

Pentachloro(pyrazine)rhenate(iv) complex as precursor of heterobimetallic pyrazine-containing ReIV2MII (M = Ni, Cu) species: synthesis, crystal struc…

2008

Three novel Re(IV) mononuclear complexes of formulae NBu4[ReC15(pyz)] (1), NH2Me2[ReCl5(pyz)] (2) and NH4[ReCl5(pyz)].0.75H2O (3), (pyz being pyrazine; NBu4+ = tetra-n-butylammonium cation, NH2Me2+ = dimethylammonium cation and NH4+ = ammonium cation), were synthesized by ligand substitution reaction from [ReCl6]2- anion and pyrazine in N,N-dimethylformamide (DMF). In addition, two new heterobimetallic compounds, the salt namely [ReCl5(pyz)]2[Ni(cyclam)](4) (cyclam = 1,4,8,11-tetraazacyclotetradecane) and the heterotrinuclear [{ReCl5(mu-pyz)}2Cu(DMF)4] (5) complex, were prepared by using as precursor 1 and 3, respectively. Compounds 1-5 were characterized by single-crystal X-ray diffraction…

Coordination Chemistry in the Solid: Study of the Incorporation of CuII into Cyclam-Containing Hybrid Materials

2001

A New Synthesis of Macrotricyclic Ligand Based on 1,4,8,11-Tetraazacyclotetradecane

1997

Abstract A convenient five-step synthesis of a cylindrical macrotricyclic ligand containing two cyclam units linked together by two m-xylyl bridges is reported starting from “trans” dioxocyclam as diprotected macrocycle.

Interaction of antimutagenic 1,4-dihydropyridine AV-153-Na with DNA and DNA-damaging molecules and its impact on DNA repair activity

2017

1,4-dihydropyridines (1,4-DHP) possess important biochemical and pharmacological properties, including antioxidant and antimutagenic activities. Interaction of some 1,4-DHP with DNA was recently reported. AV-153-Na, an antimutagenic and DNA-repair-enhancing compound appeared to be able to interact with DNA by intercalation. The aim of the current study was to characterize DNA’s capacity for the binding of AV-153-Na, and using different approaches, to test intracellular distribution of the compound, to test the ability of the compound to scavenge peroxynitrite and hydroxyl radical and to assess the ability of the compound to modify the activity of DNA repair enzymes. The DNA binding activity…

New Synthesis oftrans-Disubstituted Cyclam Macrocycles – Elucidation of the Disubstitution Mechanism on the Basis of X-ray Data and Molecular Modeling

1998

A new way to synthesize trans-disubstituted cyclam tetraazamacrocycles 1 is reported. The synthesis proceeds in three steps via the tricyclic 1,4,8,11-tetraazatricyclo[9.3.1.14,8]hexadecane system 2, which can be selectively dialkylated and hydrolyzed under basic conditions to give the final product 1. An understanding of the reactivity, based on the X-ray experimental electrostatic potential and molecular modeling of the 1,4,8,11-tetraazatricyclo[9.3.1.14,8]hexadecane macrotricycle, has permitted the elucidation of a new reaction pathway leading to the trans-disubstituted cyclam.

ChemInform Abstract: A New Synthesis of Macrotricyclic Ligand Based on 1,4,8,11- Tetraazacyclotetradecane.

2010

Abstract A convenient five-step synthesis of a cylindrical macrotricyclic ligand containing two cyclam units linked together by two m-xylyl bridges is reported starting from “trans” dioxocyclam as diprotected macrocycle.

Arylation of polyamines by perfluoroarenes

2000

Abstract The conditions of selective mono- and diarylation of diamines, and di- and triarylation of triamines by perfluoroarenes are described. The introduction of four perfluoroaryl groups in cyclam and two groups in dioxocyclam has been carried out.

First unequivocal synthesis of dissymmetrical trans N,N′-difunctionalized 1,4,8,11-tetraazacyclotetradecane

1999

Abstract The first unequivocal synthesis of disymmetrical trans N,N′-difunctionalized tetraazamacrocycles in cyclam series is reported. This convenient four-step method can be used for the synthesis of various trans N,N′-difunctionalized tetraazamacrocycles bearing two different pendant donor arms.