title: Genome and Proteome Analysis of Rhodococcus erythropolis MI2: Elucidation of the 4,4´-Dithiodibutyric Acid Catabolism.
abstract: Rhodococcus erythropolis MI2 has the extraordinary ability to utilize the xenobiotic 4,4´-dithiodibutyric acid (DTDB). Cleavage of DTDB by the disulfide-reductase Nox, which is the only verified enzyme involved in DTDB-degradation, raised 4-mercaptobutyric acid (4MB). 4MB could act as building block of a novel polythioester with unknown properties. To completely unravel the catabolism of DTDB, the genome of R. erythropolis MI2 was sequenced, and subsequently the proteome was analyzed. The draft genome sequence consists of approximately 7.2 Mbp with an overall G+C content of 62.25% and 6,859 predicted protein-encoding genes. The genome of strain MI2 is composed of three replicons: one chromosome and two megaplasmids with sizes of 6.45, 0.4 and 0.35 Mbp, respectively. When cells of strain MI2 were cultivated with DTDB as sole carbon source and compared to cells grown with succinate, several interesting proteins with significantly higher expression levels were identified using 2D-PAGE and MALDI-TOF mass spectrometry. A putative luciferase-like monooxygenase-class F420-dependent oxidoreductase (RERY_05640), which is encoded by one of the 126 monooxygenase-encoding genes of the MI2-genome, showed a 3-fold increased expression level. This monooxygenase could oxidize the intermediate 4MB into 4-oxo-4-sulfanylbutyric acid. Next, a desulfurization step, which forms succinic acid and volatile hydrogen sulfide, is proposed. One gene coding for a putative desulfhydrase (RERY_06500) was identified in the genome of strain MI2. However, the gene product was not recognized in the proteome analyses. But, a significant expression level with a ratio of up to 7.3 was determined for a putative sulfide:quinone oxidoreductase (RERY_02710), which could also be involved in the abstraction of the sulfur group. As response to the toxicity of the intermediates, several stress response proteins were strongly expressed, including a superoxide dismutase (RERY_05600) and an osmotically induced protein (RERY_02670). Accordingly, novel insights in the catabolic pathway of DTDB were gained.
authors.affiliation: Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Münster, Germany.|Botany and Microbiology Department, Faculty of Science, Alexandria University, Alexandria, Egypt.
authors.forename: Heba
authors.initials: H
authors.lastname: Khairy
authors.affiliation: Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Münster, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Meinert
authors.affiliation: Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Münster, Germany.
authors.forename: Jan Hendrik
authors.initials: JH
authors.lastname: Wübbeler
authors.affiliation: Department of Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Göttingen, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Poehlein
authors.affiliation: Department of Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Göttingen, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Daniel
authors.affiliation: Institut für Mikrobiologie, Ernst-Moritz-Arndt Universität, Greifswald, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Voigt
authors.affiliation: Institut für Mikrobiologie, Ernst-Moritz-Arndt Universität, Greifswald, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Riedel
authors.affiliation: Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Münster, Germany.|Faculty of Environmental Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Steinbüchel
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D016680:Genome, Bacterial / Q000235:genetics*; D020543:Proteome / Q000378:metabolism*; D012240:Rhodococcus / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D020543:Proteome