Capillary electrophoretic separation-based approach to determine the labeling kinetics of oligodeoxynucleotides.

With the recent advances in electron microscopy (EM), computation, and nanofabrication, the original idea of reading DNA sequence directly from an image can now be tested. One approach is to develop heavy atom labels that can provide the contrast required for EM imaging. While evaluating tentative labels for the respective nucleobases in synthetic oligodeoxynucleotides (oligos), we developed a streamlined CE protocol to assess the label stability, reactivity, and selectivity.

Binding of madindoline A to the extracellular domain of gp130.

Elevated levels of IL-6 and IL-11 are associated with multiple myeloma, rheumatoid arthritis, hypercalcemia, cancer cachexia, and Castleman's disease. Madindoline A (MadA), isolated from Streptomyces nitrosporeus K93-0711, specifically inhibits the growth of IL-6- and IL-11-dependent cell lines, most likely by interfering with the homodimerization of gp130. This raises the possibility that MadA can be used as a model compound for the development of novel chemotherapeutic agents.

Synthesis of phakellistatin 13 and oxidation to phakellistatin 3 and isophakellistatin 3.

The natural product phakellistatin 13 cyclo-(TrpProPheGlyProThrLeu) was synthesized. Photosensitized oxidation of phakellistatin 13 gave the natural products phakellistatin 3 and isophakellistatin 3, demonstrating for the first time that a tryptophan residue can be directly converted to the corresponding 3a-hydroxypyrrolo[2,3-b]indoline in a full length peptide. Competitive oxidation of the indoline product was identified as the cause of low mass balance and is probably the source of low mass balance in the oxidative cyclization of all tryptamine derivatives.

Iron(II)-catalyzed sulfimidation and [2,3]-sigmatropic rearrangement of propargyl sulfides with tert-butoxycarbonyl azide. Access to N-allenylsulfenimides.

The iron(II)-catalyzed Bach reaction of tert-butoxycarbonyl azide (BocN(3)) and allyl sulfides has been extended to include propargyl sulfides, which give N-allenylsulfenimide products. Using 10 mol % dppeFeCl(2) as catalyst the reaction proceeds at 0 degrees C with a number of different propargyl sulfides in 31-73% isolated yield. The reaction is limited by product instability toward catalyst and termination of the catalytic cycle by excess BocN(3).