Notice of RetractionAltering the Substrate Specificity of Methyl Parathion Hydrolase for Enhanced Hydrolysis of Paraoxon by Error-Prone PCR

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

The presenting author of this paper has the option to appeal this decision by contacting TPII@ieee.org.

Methyl parathion hydrolase (MPH) from Pseudomonas sp. HS-D36 has been reported to be highly specific in the hydrolysis of methyl parathion (MP) but little active towards paraoxon. In this paper, we employed error-prone polymerase chain reaction (epPCR) to obtain directed evolved MPH with enhanced ability to degrade paraoxon. After one round of epPCR, several MPH variants with improved activities towards paraoxon had been selected from the mutant library. The best mutant of rMPH-m.3 showed nearly 15-fold increased activity towards paraoxon compared with the wild type. Molecular modeling analysis suggested that the four amino acid substitutions (S180R/V268I/G308S/R318C) in the mutant MPH were not directly located in the active site but resulted in a dramatically increased binding for paraoxon. These results provided important information on directed evolution of MPH to enlarge its substrate spectrum.