New coupling reagents in peptide chemistry

Rapid photoinduced electron transfer is demonstrated over a distance of greater than 40 angstroms between metallointercalators that are tethered to the 5' termini of a 15-base pair DNA duplex. An oligomeric assembly was synthesized in which the donor is Ru(phen)2dppz2+ (phen, phenanthroline, and dppz, dipyridophenazine) and the acceptor is Rh(phi)2phen3+ (phi, phenanthrenequinone diimine). These metal complexes are intercalated either one or two base steps in from the helix termini. Although the ruthenium-modified oligonucleotide hybridized to an unmodified complement luminesces intensely, the ruthenium-modified oligomer hybridized to the rhodium-modified oligomer shows no detectable luminescence. Time-resolved studies point to a lower limit of 10(9) per second for the quenching rate. No quenching was observed upon metallation of two complementary octamers by Ru(phen)3(2+) and Rh(phen)3(3+) under conditions where the phen complexes do not intercalate. The stacked aromatic heterocycles of the DNA duplex therefore serve as an efficient medium for coupling electron donors and acceptors over very long distances.

https://science.sciencemag.org/content/sci/262/5136/1025.full.pdf

Long-range photoinduced electron transfer through a DNA helix

https://zenodo.org/record/1259711/files/article.pdf

The Functionalization of Oligonucleotides Via Phosphoramidite Derivatives

Formation of carboxamides by direct condensation of carboxylic acids and amines in alcohols using a new alcohol- and water-soluble condensing agent: DMT-MM

Referee: C. Morgan, School of Environmental and Life Sciences. University of Salford, U.K.

Time-Resolution in Fluorometry Technologies, Labels, and Applications in Bioanalytical Assays

The specific attachment of bathophenanthroline-ruthenium(II) complexes as non-radioactive label molecules to synthetically 5′-NH2-modified oligonucleotides is described. After excitation by light pulses, the fluorescence of these labels can be measured by a time-resolved mode woth high sensitivity. No quenching takes place due to coupling of the Ru complexes to the DNA. Ru-complex-labelled oligonucleotides still hybridize specifically to complementary DNA sequences, and no quenching is observed in the course of the hybridization process.

Bathophenanthroline-ruthenium(II) complexes as non-radioactive labels for oligonucleotides which can be measured by time-resolved fluorescence techniques

Robert L. Stallard

Papers

Bathophenanthroline-ruthenium(II) complexes as non-radioactive labels for oligonucleotides which can be measured by time-resolved fluorescence techniques