Detection of a single DNA base-pair mismatch using an anthracene-tagged fluorescent probe.

A novel anthracene-tagged oligonucleotide can discriminate between a fully-matched DNA target sequence and one with a single mismatching base-pair through a remarkable difference in fluorescence emission intensity upon duplex formation.

Apoptolidin A: total synthesis and partially glycosylated analogues.

The total synthesis of apoptolidin A is described employing an early glycosylation strategy. Strategic disconnections were chosen between C11-C12 (cross-coupling) and C19O-C1 (macrocyclization). The cis-selective glycosylation at C9-OH was achieved with the new SIBA protective group at O2/O3 of the L-glucose residue.

Apoptolidinone A: synthesis of the apoptolidin A aglycone.

An efficient stereocontrolled synthesis of apoptolidinone A, the aglycone of apoptolidin A is described. The synthetic strategy relies on a cross coupling between C11/C12 of a northern half (C1-C11) and a southern part (C12-C28) followed by a ring-size selective macrolactonization. Key steps for the introduction of the southern half stereocenters are a stereoselective aldol reaction, a substrate controlled dihydroxylation and a chelation-controlled Grignard/aldehyde addition.

Structural basis for Diels-Alder ribozyme-catalyzed carbon-carbon bond formation.

The majority of structural efforts addressing RNA's catalytic function have focused on natural ribozymes, which catalyze phosphodiester transfer reactions. By contrast, little is known about how RNA catalyzes other types of chemical reactions. We report here the crystal structures of a ribozyme that catalyzes enantioselective carbon-carbon bond formation by the Diels-Alder reaction in the unbound state and in complex with a reaction product.

Architecture of a Diels-Alderase ribozyme with a preformed catalytic pocket.

Artificial ribozymes catalyze a variety of chemical reactions. Their structures and reaction mechanisms are largely unknown. We have analyzed a ribozyme catalyzing Diels-Alder cycloaddition reactions by comprehensive mutation analysis and a variety of probing techniques.

Synthesis of Apoptolidinone.

A Cu -mediated coupling of the northern and southern units and a ring-size selective macrolactonization are the key steps in the convergent, first total synthesis of apoptolidinone, the aglycon of the potential antitumor compound apoptolidin. (The wavey lines in the picture are the retrosynthetic disconnections.).