Cloning and characterization of a thermostable 2- deoxy-D-ribose-5-phosphate aldolase from Aciduliprofundum boonei
Analysis of the presumptive 2-deoxy-D-ribose 5-phosphate aldolase gene from Aciduliprofundum boonei revealed an open reading frame (ORF) encoding 222 amino acids, which was subcloned and then expressed in Escherichia coli. The recombinant DERA protein was purified to apparent homogeneity. The enzyme activity was optimal at pH 7.0 and 80oC. For 2-deoxyribose-5-phosphate, the apparent Km was calculated to be 0.12 ± 0.01 mM. No loss of activity was observed after incubation at 80oC for 10 min. The enzyme was extremely stable over a wide range of pH levels. Moreover, the thermophilic enzyme also showed tolerance to acetaldehyde, which retained more than 70% activity after exposure for 4 h to 250 mM acetaldehyde at 25°C.
Key words: 2-deoxy-D-ribose 5-phosphate aldolase (DERA), thermophiles, aldo condensation.