Elucidation of the 4-hydroxyacetophenone catabolic pathway in Pseudomonas fluorescens ACB

M.J.H. Moonen, N.M. Kamerbeek, A.H. Westphal, J.A. Boeren, D.B. Janssen, M.W. Fraaije, W.J.H. van Berkel

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Abstract

The catabolism of 4-hydroxyacetophenone in Pseudomonas fluorescens ACB is known to proceed through the intermediate formation of hydroquinone. Here we provide evidence that hydroquinone is further degraded through 4-hydroxymuconic semialdehyde and maleylacetate to -ketoadipate. The P. fluorescens ACB genes involved in 4-hydroxyacetophenone utilization were cloned and characterized. Sequence analysis of an 15-kb DNA fragment showed the presence of fourteen open reading frames containing a gene cluster (hapCDEFGHIBA) of which at least four encoded enzymes are involved in 4-hydroxyacetophenone degradation: 4-hydroxyacetophenone monooxygenase (hapA), 4-hydroxyphenyl acetate hydrolase (hapB), 4-hydroxymuconic semialdehyde dehydrogenase (hapE) and maleylacetate reductase (hapF). In between hapF and hapB, three genes encoding a putative intradiol dioxygenase (hapG), a protein of the yci1 family (hapH) and a [2Fe-2S] ferredoxin (hapI) were found. Downstream of the hap genes, five open reading frames are situated encoding three putative regulatory proteins (orf10, orf12 and orf13) and two proteins possibly involved in a membrane efflux pump (orf11 and orf14). Upstream of hapE, two genes (hapC and hapD) were present that showed weak similarity with several iron (II)-dependent extradiol dioxygenases. Based on these findings and additional biochemical evidence it is proposed that the hapC and hapD gene products are involved in the ring-cleavage of hydroquinone.
Original languageEnglish
Pages (from-to)5190-5198
JournalJournal of Bacteriology
Volume190
DOIs
Publication statusPublished - 2008

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Keywords

  • meta-cleavage pathway
  • cleaving catecholic dioxygenase
  • baeyer-villiger monooxygenase
  • candida-parapsilosis cbs604
  • plasmid-encoded degradation
  • sp strain b13
  • crystal-structure
  • gene-cluster
  • p-nitrophenol
  • hydroxyquinol 1,2-dioxygenase

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