A new phosphotriesterase from Sulfolobus acidocaldarius and its comparison with the homologue from Sulfolobus solfataricus.
The phosphotriesterase PTE, identified in the soil bacterium Pseudomonas diminuta, is thought to have evolved in the last several decades to degrade the pesticide paraoxon with proficiency approaching the limit of substrate diffusion (k(cat)/K(M) of 4 x 10(7)M(-1)s(-1)). It belongs to the amidohydrolase superfamily, but its evolutionary origin remains obscure. The enzyme has important potentiality in the field of the organophosphate decontamination. Recently we reported on the characterization of an archaeal member of the amidohydrolase superfamily, namely Sulfolobus solfataricus, showing low but significant and extremely thermostable paraoxonase activity (k(cat)/K(M) of 4 x 10(3)M(-1)s(-1)). Looking for other thermostable phosphotriesterases we assayed, among others, crude extracts of Sulfolobus acidocaldarius and detected activity. Since the genome of S. acidocaldarius has been recently reported, we identified there an open reading frame highly related to the S. solfataricus enzyme. The gene was cloned, the protein overexpressed in Escherichia coli, purified, and proven to have paraoxonase activity. A comparative analysis detected some significant differences between the two archaeal enzymes.
Porzio
Elena
E
Istituto di Biochimica delle Proteine, Consiglio Nazionale delle Ricerche, via P. Castellino 111, 80131 Naples, Italy.
Merone
Luigia
L
Mandrich
Luigi
L
Rossi
Mosè
M
Manco
Giuseppe
G
D043303:Aryldialkylphosphatase / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D052918:Environmental Restoration and Remediation / Q000379:methods*; D019143:Evolution, Molecular; D016680:Genome, Bacterial; D007700:Kinetics; D016366:Open Reading Frames; D010755:Organophosphates / Q000378:metabolism; D010261:Paraoxon / Q000378:metabolism; D010575:Pesticides / Q000378:metabolism; D044345:Phosphoric Triester Hydrolases / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D016945:Sulfolobus acidocaldarius / Q000201:enzymology*; D048229:Sulfolobus solfataricus / Q000201:enzymology*
D010755:Organophosphates; D010575:Pesticides; D044345:Phosphoric Triester Hydrolases; D043303:Aryldialkylphosphatase; D010261:Paraoxon