Characterization of a novel meta-fission product hydrolase from Dyella ginsengisoli LA-4

A novel meta-fission product hydrolase gene (mfphA) located in the bphX gene region of Dyella ginsengisoli LA-4 was successfully cloned and heterologously expressed in this study. The deduced amino acid sequence of MfphA showed 75% identity with the sequence of 2-hydroxymuconic semialdehyde hydrolase from Pseudomonas putida UCC22. The results suggested that MfphA belonged to the α/β hydrolase family, which could hydrolyze the meta-fission products (MFPs) during the biodegradation process of monocyclic compounds. The His-Tag MfphA was purified, and the subunit molecular mass of MfphA was about 35.3 kDa by SDS-PAGE analysis. According to the apparent kinetic parameters, the specificity of MfphA was determined in the following order: 6-methyl-HODA > HODA > 5-methyl-HODA > 6-phenyl-HODA > 5-chloro-HODA (HODA, 2-hydroxy-6-oxohexa-2,4-dienoate). The activity of MfphA for HODA was higher than that for 6-methyl-HODA. It was shown that the maximum activity was at 70 °C, and MfphA was stable for storage at low temperature for 30 days.