Characterization of a polycyclic aromatic ring-hydroxylation dioxygenase from Mycobacterium sp. NJS-P.

Ring-hydroxylating dioxygenases (RHDs) play a critical role in the biodegradation of polycyclic aromatic hydrocarbons (PAHs). In this study, genes pdoAB encoding a dioxygenase capable of oxidizing various PAHs with up to five-ring benzo[a]pyrene were cloned from Mycobacterium sp. NJS-P. The α-subunit of the PdoAB showed 99% and 93% identity to that from Mycobacterium sp. S65 and Mycobacterium sp. py136, respectively. An Escherichia coli expression experiment revealed that the enzyme is able to oxidize anthracene, phenanthrene, pyrene and benzo[a]pyrene, but not to fluoranthene and benzo[a]anthracene. Furthermore, the results of in silico analysis showed that PdoAB has a large substrate-binding pocket satisfying for accommodation of HMW PAHs, and suggested that the binding energy of intermolecular interaction may predict the substrate conversion of RHDs towards HMW PAHs, especially those may have steric constraints on the substrate-binding pocket, such as benzo[a]pyrene and benzo[a]anthracene.

Zeng J ，Zhu Q ，Wu Y ，Chen H ，Lin X ... -  《-》

Mutation of Phenylalanine-223 to Leucine Enhances Transformation of Benzo[a]pyrene by Ring-Hydroxylating Dioxygenase of Sphingobium sp. FB3 by increasing Accessibility of the Catalytic Site.

Fu B ，Xu T ，Cui Z ，Ng HL ，Wang K ，Li J ，Li QX ... -  《-》

Identification of A Ring-Hydroxylating Dioxygenases Capable of Anthracene and Benz[a]anthracene Oxidization from Rhodococcus sp. P14.

Nowadays, contamination of soil and marine sediments by polycyclic aromatic hydrocarbons (PAHs) has become a serious problem all over the world. Rhodococcus sp. P14 was isolated from sediments with crude oil contaminate and showed degradation ability on various PAHs. The genome of Rhodococcus sp. P14 was sequenced. A gene cluster encoding a ring-hydroxylating dioxygenase Baa related to PAH degradation was identified by bioinformatics. The expression level of gene baaA was increased when P14 was cultured with anthracene, pyrene, phenanthrene, or benz[a]-anthracene as the single carbon source. The recombinant protein Baa was overexpressed in E. coli BL21 (DE3). Further investigations on the recombinant protein Baa in E. coli demonstrated that it was able to oxidize anthracene and benz [a]anthracene, resulting in 9,10-dihydroxyanthracene and 7, 12-dihydroxybenz[a]anthracene as metabolites, respectively. These results indicate that Baa plays an important role in PAH degradation in Rhodococcus sp. P14 and Baa has potential application in the bioremediation of PAHs in the contaminated environment.

Peng T ，Luo A ，Kan J ，Liang L ，Huang T ，Hu Z ... -  《-》

Cloning and functional study of a novel aromatic-ring-hydroxylating dioxygenase gene.

Zhou HW ，Zhou MJ 《-》

Isolation and characterization of a gene cluster involved in PAH degradation in Mycobacterium sp. strain SNP11: expression in Mycobacterium smegmatis mc(2)155.

Pagnout C ，Frache G ，Poupin P ，Maunit B ，Muller JF ，Férard JF ... -  《-》