Expression and characterization of a novel 2-deoxyribose-5-phosphate aldolase from Haemophilus influenzae Rd KW20

A codon-optimized 2-deoxyṟibose-5-phosphate aldolase (DERA) gene from Haemophilus influenzae Rd KW20 was synthesized and expressed in Escherichia coli, and the biochemical properties of its product were investigated. DERA was purified using affinity chromatography and characterized using 2-deoxyribose-5-phosphate as the substrate. Specific activity of the recombinant DERA was 34.1 Umg⁻¹. The pH and temperature optima were 7.5 and 40°C, respectively. Additionally, the recombinant enzyme retained stability up to temperatures below 50°C. Maximal enzyme activity was observed in presence of 300 mM of acetaldehyde. The apparent K_m and V_max of purified enzyme towards 2-deoxyribose-5-phosphate were 0.14 mM and 70.42 μmol min⁻¹ mg⁻¹ and towards 2-deoxy-D-ribose were 24.77 mM and 1.94 μmol min⁻¹ mg⁻¹, respectively. For synthesis of statin intermediates, the bioconversion process for production of (3R, 5S)-6-chloro-2,4,6-trideoxy-erythro-hexose from chloroacetaldehyde and acetaldehyde using the recombinant DERA was studied and this process took 3 h for maximal conversion. This recombinant DERA could be potentially applied in the production of (3R, 5S)-6-chloro-2,4,6-trideoxy-erythro-hexose.