Double strand DNA cleavage with a binuclear iron complex.
Covalently linking two single strand DNA cleaving agents resulted in a new biomimetic binuclear iron complex capable of effecting oxidative double strand DNA cleavage.
DNA↗
Biomedical subjects
Tieme A van den Berg
Publications and source records attributed to Tieme A van den Berg.
Electronic properties, redox behavior, and interactions with H2O2 of pH-sensitive hydroxyphenyl-1,2,4-triazole-based oxovanadium(V) complexes.
The syntheses and spectroscopic characterization of two 1,2,4-triazole-based oxovanadium(V) complexes are reported: 1- [VO2L1]- and 2 [(VOL2)2(OMe)2] (where H2L1 = 3-(2'-hydroxyphenyl)-5-(pyridin-2' '-yl)-1H-1,2,4-triazole, H3L2 = bis-3,5-(2'-hydroxyphenyl)-1H-1,2,4-triazole). The ligand environment (N,N,O vs O,N,O) is found to have a profound influence on the properties and reactivity of the complexes formed. The presence of the triazolato ligand allows for pH tuning of the spectroscopic and electrochemical properties, as well as the interaction and stability of the complexes in the presence of hydrogen peroxide. The vanadium(IV) oxidation states were generated electrochemically and characterized by UV-vis and EPR spectroscopies. For 2, under acidic conditions, rapid exchange of the methoxide ligands with solvent [in particular, in the vanadium(IV) redox state] was observed.
Crystallography, X-Ray↗
Spin-state rationale for the peroxo-stabilizing role of the thiolate ligand in superoxide reductase.
Explore the source record for details and available documents.
Ligands↗
Enhanced selectivity in non-heme iron catalysed oxidation of alkanes with peracids: evidence for involvement of Fe(IV)=O species.
Catalytic alkane oxidation with high selectivity using peracids and an (N4Py)Fe complex is presented and the role of [(N4Py)Fe(IV)=O]2+ species, molecular oxygen and hydroxyl radicals in the catalysis is discussed.
Journal Article↗
Synthesis of a non-heme template for attaching four peptides: an approach to artificial iron(II)-containing peroxidases.
We are developing all-synthetic model cofactor-protein complexes in order to define the parameters controlling non-natural cofactor activity. The long-term objective is to establish the theoretical and practical basis for designing novel enzymes. A non-heme pentadentate ligand (N4Py) is being developed as a template for the site-specific attachment of a designed four-helix bundle. Previously, we attached two unprotected peptides via CH(2)Cl handles to N4Py. In the presence of hydrogen peroxide, the iron(II) complex of this ligand (2a) generates an Fe(III)OOH intermediate (3a) that can oxidize a wide variety of organic compounds. Here, we describe the synthesis of 27, a N4Py derivative in which four three-carbon spacers have been introduced, and show that four copies of an unprotected, single-cysteine peptide can be coupled via a thioether linkage to the ligand. In addition, a divergent synthesis route to tetrabromide ligand 1b has also been developed, providing the opportunity to prepare alternative pentadentate ligands efficiently by four cross-coupling reactions on a single molecule. Also, two of the four bromides of 1b can be selectively addressed by magnesium-bromide exchange.
Heme↗