title: The unique aromatic catabolic genes in sphingomonads degrading polycyclic aromatic hydrocarbons (PAHs).
abstract: Many members of the sphingomonad genus isolated from different geological areas can degrade a wide variety of polycyclic aromatic hydrocarbons (PAHs) and related compounds. These sphingomonads such as Sphingobium yanoikuyae strain B1, Novosphingobium aromaticivorans strain F199, and Sphingobium sp. strain P2 have been found to possess a unique group of genes for aromatic degradation, which are distantly related with those in pseudomonads and other genera reported so far both in sequence homology and gene organization. Genes for aromatics degradation in these sphingomonads are complexly arranged; the genes necessary for one degradation pathway are scattered through several clusters. These aromatic catabolic gene clusters seem to be conserved among many other sphingomonads such as Sphingobium yanoikuyae strain Q1, Sphingomonas paucimobilis strain TNE12, S. paucimobilis strain EPA505, Sphingobium agrestis strain HV3, and Sphingomonas chungbukensis strain DJ77. Furthermore, some genes for naphthalenesulfonate degradation found in Sphingomonas xenophaga strain BN6 also share a high sequence homology with their homologues found in these sphingomonads. On the other hand, protocatechuic catabolic gene clusters found in fluorene-degrading Sphingomonas sp. strain LB126 appear to be more closely related with those previously found in lignin-degrading S. paucimobilis SYK-6 than the genes in this group of sphingomonads. This review summarizes the information on the distribution of these strains and relationships among their aromatic catabolic genes.
authors.affiliation: Biotechnology Research Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Onruthai
authors.initials: O
authors.lastname: Pinyakong
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Habe
authors.forename: Toshio
authors.initials: T
authors.lastname: Omori
mesh_terms: D020561:Alphaproteobacteria / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D001673:Biodegradation, Environmental; D005075:Biological Evolution; D001713:Biphenyl Compounds / Q000737:chemistry / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D005449:Fluorenes / Q000737:chemistry / Q000378:metabolism; D005798:Genes, Bacterial; D008957:Models, Genetic; D015394:Molecular Structure; D010802:Phylogeny; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry / Q000378:metabolism*; D012988:Soil Microbiology
chemical_list: D001713:Biphenyl Compounds; D004269:DNA, Bacterial; D005449:Fluorenes; D011084:Polycyclic Aromatic Hydrocarbons; C010574:biphenyl; C007738:fluoranthene