Highly sensitive protein detection based on lanthanide chelates with antenna ligands providing a linear range of five orders of magnitude.

Protein detection is an important task for pharmaceutical and clinical research today. Numerous protein staining techniques exist but are limited regarding their sensitivity and often narrow linear quantification ranges. To the best of our knowledge, this is the first description of a novel class of lanthanide chelatators, which absorb in the lower energy region at 360 nm. The new compound (6,9-dicarboxymethyl-3-{4-([1,10]-phenanthrol-2-ylethinylphenyl-carbamoyl)-methyl}-3,6,9-triaza-)-undeca-1,11-dicarboxylic acid) was coupled to different proteins and showed highly sensitive protein detection limits in both sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) (1.5 fmol of bovine serum albumin) as well as Dot Blot (100 amol of lysozyme). Furthermore, the novel compound shows an exceptionally broad linear quantification range over 5 orders of magnitude allowing applications that require the highest sensitivity alongside standard sensitivity. In addition, the new compound offers multiplexing capabilities.

Molecular structures and electronic transitions of 3,6-diphenyl-1,2-dithiin and its radical cation: a spectroelectrochemical and DFT study.

One-electron oxidation of 3,6-diphenyl-1,2-dithiin yields the corresponding radical cation. The product is stable at low temperatures and can be distinguished by a triplet EPR signal. Cyclic voltammetric, UV-vis spectroelectrochemical, and DFT studies were performed to elucidate its molecular structure and electronic properties. Time-dependent DFT calculations reproduce appreciably well the UV-vis spectral changes observed during the oxidation. The results reveal a moderately twisted structure of the 1,2-dithiin heterocycle in the radical cation.

Isoserine-based biotinylated photoaffinity probes that interact with penicillin-binding protein 1b.

The photolytic decomposition of trifunctional carbene generating photoaffinity probes in methanolic solution was studied, a cleavage reaction with butylamine in water, the conjugation with a ligand (moenomycin), and experiments that demonstrate that the fully armed probes interact with penicillin-binding protein 1b.