A series of novel modifying reagents, including phosphoramidites and solid supports, have been synthesized, and used for the introduction of 1‐(phenylethynyl)pyrene (PEPy) and 9,10‐bis(phenylethynyl)anthracene (BPEA) fluorescent dyes into predetermined positions of synthetic oligonucleotides. These two fluorophores have been shown to constitute an energy donor−acceptor pair, and can be used as such in fluorescent oligonucleotide probes, designed for the detection and structural studies of nucleic acids. The sensitivity of the probe to duplex formation is demonstrated. The formation of the PEPy and BPEA excimers is reported for the first time on nucleic acids. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

We report a novel family of natural lipoglycopeptides produced by Streptomyces sp. INA-Ac-5812. Two major components of the mixture, named gausemycins A and B, were isolated, and their structures were elucidated. The compounds are cyclic peptides with a unique peptide core and several remarkable structural features, including unusual positions of D-amino acids, lack of the Ca 2+ -binding Asp-X-Asp-Gly (DXDG) motif, tyrosine glycosylation with arabinose, presence of 2-amino-4-hydroxy-4-phenylbutyric acid (Ahpb) and chlorinated kynurenine (ClKyn), N-acylation of the ornithine side chain. These major components of the peptide antibiotic family have pronounced activity against Grampositive bacteria. The mechanism of action of gausemycins was explored by a number of methods, showing significant differences compared to glycopeptides and related lipopeptides. Gausemycins exhibit only slight Ca 2+ -dependence of antimicrobial activity and induce no pore formation at low concentrations. Moreover, there is no detectable accumulation of cell wall biosynthesis precursors under treatment with gausemycins.

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