title: Identification and functional analysis of the genes for naphthalenesulfonate catabolism by Sphingomonas xenophaga BN6.
abstract: Sphingomonas xenophaga BN6 degrades various (substituted) naphthalenesulfonates to the corresponding (substituted) salicylates. A gene cluster was identified on the plasmid pBN6 which coded for several enzymes participating in the degradative pathway for naphthalenesulfonates. A DNA fragment of 16 915 bp was sequenced which contained 17 ORFs. The genes encoding the 1,2-dihydroxynaphthalene dioxygenase, 2-hydroxychromene-2-carboxylate isomerase, and 2'-hydroxybenzalpyruvate aldolase of the naphthalenesulfonate pathway were identified on the DNA fragment and the encoded proteins heterologously expressed in Escherichia coli. Also, the genes encoding the ferredoxin and ferredoxin reductase of a multi-component, ring-hydroxylating naphthalenesulfonate dioxygenase were identified by insertional inactivation. The identified genes generally demonstrated the highest degree of homology to enzymes encoded by the phenanthrene-degrading organism Sphingomonas sp. P2, or the megaplasmid pNL1 of the naphthalene- and biphenyl-degrading strain Sphingomonas aromaticivorans F199. The genes of S. xenophaga BN6 participating in the degradation of naphthalenesulfonates also shared the same organization in three different transcriptional units as the genes involved in the degradation of naphthalene, biphenyl, and phenanthrene previously found in Sphingomonas sp. P2 and S. aromaticivorans F199. The genes were flanked in S. xenophaga BN6 by ORFs which specify proteins that show the highest homologies to proteins of mobile genetic elements.
authors.affiliation: Institut für Industrielle Genetik, Universität Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Keck
authors.affiliation: Institut für Industrielle Genetik, Universität Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany.
authors.forename: Doris
authors.initials: D
authors.lastname: Conradt
authors.affiliation: Institut für Industrielle Genetik, Universität Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany.
authors.forename: Anette
authors.initials: A
authors.lastname: Mahler
authors.affiliation: Institut für Mikrobiologie, Universität Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Stolz
authors.affiliation: Institut für Industrielle Genetik, Universität Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Mattes
authors.affiliation: Institut für Industrielle Genetik, Universität Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Klein
mesh_terms: D001483:Base Sequence; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009282:Naphthalenesulfonates / Q000378:metabolism*; D016366:Open Reading Frames; D020578:Sphingomonas / Q000235:genetics* / Q000378:metabolism
chemical_list: D009282:Naphthalenesulfonates