Open AccessThe Locus Coding for the 3-Nitrobenzoate Dioxygenase of Comamonas sp. Strain JS46 Is Flanked by IS 1071 Elements and Is Subject to Deletion and Inversion Events
Author(s) -
Miguel A. Providenti,
Rachel E. Shaye,
Krista D. Lynes,
Neil McKenna,
Jason M. O’Brien,
Sarah Rosolen,
R. Campbell Wyndham,
Iain Lambert
Publication year - 2006
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.72.4.2651-2660.2006
Subject(s) - insertion sequence , comamonas , genetics , biology , locus (genetics) , dioxygenase , plasmid , direct repeat , microbiology and biotechnology , gene , transposable element , bacteria , pseudomonas , base sequence , genome
InComamonas sp. strain JS46, 3-nitrobenzoate (3Nba) is initially oxidized at the 3,4 position by a dioxygenase, which results in release of nitrite and production of protocatechuate. The locus coding for the 3Nba dioxygenase (designatedmnb , form-n itrob enzoate) was mobilized from strain JS46 using a plasmid capture method, cloned, and sequenced. The 3Nba dioxygenase (MnbA) is a member of the phthalate family of aromatic oxygenases. An open reading frame designatedmnbB that codes for an NAD(P)H-dependent class IA aromatic oxidoreductase is downstream ofmnbA . MnbB is tentatively identified as the oxidoreductase that transfers reducing equivalents to MnbA in strain JS46. Themnb locus is flanked by IS1071 elements. The upstream element is interrupted by a novel insertion sequence designated ISCsp1 , and the transposase genes of the flanking insertion elements are transcribed in the direction opposite the direction ofmnbA transcription. Spontaneous deletion ofmnb occurs because of homologous recombination between the directly repeated flanking IS1071 elements. In addition, in ∼0.007 to 0.2% of any population of JS46 cells growing on 3Nba, alternative orientations ofmnb relative to the flanking IS1071 elements are detected. These alternative forms are the result of inversions ofmnb and the flanking IS1071 elements. Inversions appear to occur because of homologous recombination between the inverted repeats that flank the IS1071 elements.