A mutant D-fructose-6-phosphate aldolase (Ala129Ser) with improved affinity towards dihydroxyacetone for the synthesis of polyhydroxylated compounds

Article abstract of DOI:10.1002/adsc.200900772

A mutant of D-fructose-6-phosphate aldo-lase (FSA) of Escherichia coli, FSA A129S, with im-proved catalytic efficiency towards dihydroxyacetone (DHA), the donor substrate in aldol addition reac-tions, was explored for synthetic applications. The K_cat/K_M value for DHA was 17-fold higher with FSA A129S than that with FSA wild type (FSA wt). On the other hand, for hydroxyacetone as donor sub-strate FSA A129S was found to be 3.5-fold less effi-cient than FSA wt. Furthermore, FSA A129S also ac-cepted glycolaldehyde (GA) as donor substrate with 3.3-fold lower affinity than FSA wt. This differential selectivity of both FSA wt and FSA A129S for GA makes them complementary biocatalysts allowing a control over donor and acceptor roles, which is par-ticularly useful in carboligation multi-step cascade synthesis of polyhydroxylated complex compounds. Production of the mutant protein was also improved for its convenient use in synthesis. Several carbohy-drates and nitrocyclitols were efficiently prepared, demonstrating the versatile potential of FSA A129S as biocatalyst in organic synthesis.