A novel degradation pathway of chloroaniline in Diaphorobacter sp. PCA039 entails initial hydroxylation.----中国科学院微生物研究所

科研成果

论文题目:	A novel degradation pathway of chloroaniline in Diaphorobacter sp. PCA039 entails initial hydroxylation.
作者:	Tao Zhang, Huafeng Ren, Ying Liu, Baoli Zhu and Zhipei Liu*
联系作者:	刘志培
刊物名称:	World Journal of Microbiology & Biotechnology
期:
卷:	26
页:	665-673
年份:	2010
影响因子:	0.945
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摘要:	A novel degradation pathway of chloroaniline in Diaphorobacter sp. PCA039 entails initial hydroxylation. A novel gene cluster (pca), involved in the degradation of p-chloroaniline, was identified from Diaphorobacter sp. PCA039 capable of utilizing p-chloroaniline as sole carbon, nitrogen and energy source for growth. There were 29 ORFs in the pca cluster, in the order of pcaTRKLMNOPR 1 D 1 C I U 1 R 2 D 2 C 2 U 2 EFGXJHYWZI 1 I 2 QS. Based on sequence analysis, they were putatively identified as encoding a multicomponent phenol-hydroxylating oxygenase (pcaKLMNOP), two extradiol ring-cleavage dioxygenases, transcriptional regulatory proteins, enzymes mediating chlorocatechol degradation, and transportation functions. The genes pcaKLMNOP exhibited significant sequence identity (94%) to those of phenol hydroxylases (PH) from other bacteria, inferring that they might encode a multicomponent PH. This PH activity was also functionally characterized with the recombinant strain E. coli TOP10-S201 showing only PH activity, indicating that the degradation of p-chloroaniline by strain PCA039 was initiated by hydroxylation instead of normal dioxygenation. The other nineteen genes, pcaR 1 D 1 C I U 1 R 2 D 2 C 2 U 2 EFGXJHYWZI 1 I 2 , encode for further degradation of p-chloroaniline to intermediates of the TCA-cycle and transposases. RT-PCR revealed that the hydrolytic (pcaF) and dehydrogenetic pathways (pcaE, pcaH), the two degrading branches, are both necessary for complete degradation of aniline, p-chloroaniline, phenol and also 4-aminophenol; and of the two C23O sets, PcaR1D1C1U1 and PcaR2D2C2U2, PcaC1 is produced in the degradation of above four substrates, while PcaC2 is only expressed in p-chloroaniline degradation, suggesting that both C23O sets are needed for complete degradation of p-chloroaniline.