Structure-based rationalization of aldolase-catalyzed asymmetric synthesis

Abstract

This paper describes a structure-based approach to elucidate the stereospecificity, including inversion of enantioselectivity, of the 2-deoxyribose-5-phosphate aldolase-catalyzed asymmetric aldol addition reaction using unnatural substrates designed for the total synthesis of epothilones. In addition, an aldolase variant with Ser-238 being altered for Asp was found to be 2.5 times more effective than the wild type in accepting the unphosphorylated substrate D-glyceraldehyde. A new H-bonding interaction between the Asp-238 carboxylate and the 3-hydroxyl of the substrate was identified and was used to rationalize the rate enhancements.Key words: aldol reaction, 2-deoxyribose-5-phosphate aldolase, mutagenesis, inversion of enantioselectivity.