Title |
Molecular Characterization of the Alpha Subunit of Multicomponent Phenol Hydroxylase from 4-Chlorophenol-Degrading Pseudomonas sp. Strain PT3 |
Author |
Wael S. El-Sayed1,2, Mohamed K. Ibrahim2, and Salama A. Ouf1,3 |
Address |
1Biology Department, Faculty of Science, Taibah University, 344, Almadinah Almunwarrah, KSA, 2Microbiology Department, Faculty of Science, Ain Shams University, 11566, Cairo, Egypt, 3Botany Department, Faculty of Science, Cairo University, Giza 12613, Egypt |
Bibliography |
Journal of Microbiology, 52(1),13–19, 2014,
|
DOI |
10.1007/s12275-014-3250-x
|
Key Words |
4-chlorophenol, biodegradation, phenol hydroxylase, catalytic domain, Pseudomonas |
Abstract |
Multicomponent phenol hydroxylases (mPHs) are diiron
enzymes that use molecular oxygen to hydroxylate a variety
of phenolic compounds. The DNA sequence of the alpha
subunit (large subunit) of mPH from 4-chlorophenol (4-CP)-
degrading bacterial strain PT3 was determined. Strain PT3
was isolated from oil-contaminated soil samples adjacent
to automobile workshops and oil stations after enrichment
and establishment of a chlorophenol-degrading consortium.
Strain PT3 was identified as a member of Pseudomonas sp.
based on sequence analysis of the 16S rRNA gene fragment.
The 4-CP catabolic pathway by strain PT3 was tentatively
proposed to proceed via a meta-cleavage pathway after hydroxylation
to the corresponding chlorocatechol. This hypothesis
was supported by polymerase chain reaction (PCR)
detection of the LmPH encoding sequence and UV/VIS spectrophotometric
analysis of the culture filtrate showing accumulation
of 5-chloro-2-hydroxymuconic semialdehyde
(5-CHMS) with λmax 380. The detection of catabolic genes
involved in 4-CP degradation by PCR showed the presence of
both mPH and catechol 2,3-dioxygenase (C23DO). Nucleotide
sequence analysis of the alpha subunit of mPH from strain
PT3 revealed specific phylogenetic grouping to known mPH.
The metal coordination encoding regions from strain PT3
were found to be conserved with those from the homologous
dinuclear oxo-iron bacterial monooxygenases. Two
DE(D)XRH motifs was detected in LmPH of strain PT3
within an approximate 100 amino acid interval, a typical
arrangement characteristic of most known PHs. |