Sequential Aldol Condensation Catalyzed by 2-Deoxy-D-Ribose -5-Phosphate Aldolase (DERA)
Eman M. M. Abdelraheem, Fabio Tonin, Peter-Leon Hagedoorn and Ulf Hanefeld
Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
2-deoxy-d-ribose-5-phosphate aldolase (DERA) is a class 1 aldolase that offers access to several building blocks for organic synthesis by catalyzing a stereoselective C-C bond formation between acetaldehyde and numerous other aldehydes [1]. However, the practical application of DERA as a biocatalyst is limited by its poor tolerance towards industrially relevant concentrations of acetaldehyde.
Here, we describe our studies with the acetaldehyde tolerant DERA lb [2]. The gene encoding DERA lb from Lactobacillus brevis ECU8302 was expressed in Escherichia coli and a point mutation E78K was introduced to improve both the acetaldehyde resistance of the enzyme and its thermostability. The structures and activities of the two enzymes were characterized and compared with those of E. coli DERA. The two DERA lb variants showed much greater activity in the sequential aldol condensation reaction (using acetaldehydes and 2-substituted acetaldehydes as substrates) than the E. coli ortholog. At 25 °C and 300 mM acetaldehyde, the chiral lactol intermediate was obtained in good yield. This intermediate is a synthon for the preparation of a large variety of optically pure super-statins, such as Rosuvastatin and Pitavastatin.
[1] Meera Haridas, Eman M. M. Abdelraheem, Ulf Hanefeld, 2-Deoxy-D-ribose-5-phosphate aldolase (DERA): applications and modifications, Appl. Microbiol. Biotechnol., 2018, 102, 9959–9971.
[2] Xue-Cheng Jiao, Jiang Pan, Guo-Chao Xu, Xu-Dong Kong, Qi Chen, Zhi-Jun Zhang and Jian-He Xu, Efficient synthesis of a statin precursor in high space-time yield by a new aldehyde-tolerant aldolase identified from Lactobacillus brevis, Catal. Sci. Technol., 2015, 5, 4048–4054.
