Synthesis, stereochemical characterization, and antimicrobial evaluation of a potentially nonnephrotoxic 3'-C-acethydrazide puromycin analog.

Puromycin is a peptidyl nucleoside endowed with significant antibiotic and anticancer properties, but also with an unfortunate nephrotoxic character that has hampered its use as a chemotherapeutic agent. Since hydrolysis of puromycin's amide to puromycin aminonucleoside is the first metabolic step leading to nephrotoxicity, we designed a 3'-C-hydrazide analog where the nitrogen and carbon functionality around the amide carbonyl of puromycin are inverted. The title compound, synthesized in 11 steps from D-xylose, cannot be metabolized to the nephrotoxic aminonucleoside.

Enantioselectivity and Enzyme-Substrate Docking Studies of a Ketoreductase from Sporobolomyces salmonicolor (SSCR) and Saccharomyces cerevisiae (YOL151w).

Models for two ketoreductases were created and used to predict the stereoselectivity of the enzymes. One was based on the crystal structure of Sporobolomyces salmonicolor. This model was used to predict the stereoselectivity for 46 ketone reductions using this enzyme; only 6 were incorrectly predicted.

Using biocatalysis to integrate organic chemistry into a molecular biology laboratory course.

Current cutting-edge biomedical investigation requires that the researcher have an operational understanding of several diverse disciplines. Biocatalysis is a field of science that operates at the crossroads of organic chemistry, biochemistry, microbiology, and molecular biology, and provides an excellent model for interdisciplinary research. We have developed an inquiry-based module that uses the mutagenesis of the yeast reductase, YDL124w, to study the bioorganic synthesis of the taxol side-chain, a pharmacologically important molecule.

Enantiodivergent, biocatalytic routes to both taxol side chain antipodes.

[Reaction: see text]. Two enantiocomplementary bakers' yeast enzymes reduced an alpha-chloro-beta-keto ester to yield precursors for both enantiomers of the N-benzoyl phenylisoserine Taxol side chain. After base-mediated ring closure of the chlorohydrin enantiomers, the epoxides were converted directly to the oxazoline form of the target molecules using a Ritter reaction with benzonitrile.

Stereoselective, biocatalytic reductions of alpha-chloro-beta-keto esters.

Eighteen known and putative reductases from baker's yeast (Saccharomyces cerevisiae) were tested for the ability to reduce a series of alpha-chloro-beta-keto esters. In nearly all cases, it was possible to produce at least two of the four possible alpha-chloro-beta-hydroxy ester diastereomers with high optical purities. The utility of this approach was demonstrated by reducing ethyl 2-chloroacetoacetate to the corresponding syn-(2R,3S)-alcohol on a multigram scale using whole cells of an Escherichia coli strain overexpressing a single yeast reductase identified from the screening studies.