Document Detail


Insertional gene inactivation in a phototrophic sulphur bacterium: APS-reductase-deficient mutants of Chromatium vinosum.
MedLine Citation:
PMID:  9004500     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In purple sulphur bacteria of the family Chromatiaceae sulphite oxidation via intermediary formation of adenylylsulphate is an enzymologically well characterized process. In contrast, the role of an alternative direct oxidation pathway via the enzyme sulphite:acceptor oxidoreductase has not been resolved. This paper reports the cloning of the genes encoding the adenylylsulphate-forming enzyme adenosine-5'-phosphosulphate (APS) reductase from Chromatium vinosum strain D (DSM 180'), a representative of the purple sulphur bacteria, and the construction of mutations in these genes by insertion of a kanamycin omega cartridge. The mutated genes were transferred to C. vinosum on suicide vectors of the pSUP series by conjugation and delivered to the chromosome by double homologous recombination. Southern hybridization and PCR analyses of the recombinants obtained verified the first insertional gene inactivation in purple sulphur bacteria. Enzymological studies demonstrated the absence of APS reductase from the mutants. Further phenotypic characterization showed no significant effect of APS reductase deficiency on the sulphite-oxidizing ability of the cells under photolithoautotrophic growth conditions. In the wild-type as well as in mutant strains, tungstate, the specific antagonist of molybdate, led to the intermediary accumulation of sulphite in the medium during sulphide oxidation and strongly inhibited growth with sulphite as photosynthetic electron donor; this indicates that a molybdoenzyme, probably sulphite:acceptor oxidoreductase, is the main sulphite-oxidizing enzyme in C. vinosum. Specific inactivation of selected genes as developed for C. vinosum in this study provides a powerful genetic tool for further analysis of sulphur metabolism and other metabolic pathways in phototrophic sulphur bacteria.
Authors:
C Dahl
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Microbiology (Reading, England)     Volume:  142 ( Pt 12)     ISSN:  1350-0872     ISO Abbreviation:  Microbiology (Reading, Engl.)     Publication Date:  1996 Dec 
Date Detail:
Created Date:  1997-02-27     Completed Date:  1997-02-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9430468     Medline TA:  Microbiology     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  3363-72     Citation Subset:  IM    
Affiliation:
Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany. ChDahl@uni-bonn.de
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MeSH Terms
Descriptor/Qualifier:
Chromatium / enzymology*,  genetics*,  growth & development
Cloning, Molecular
Conjugation, Genetic
DNA Primers
Escherichia coli
Genes, Bacterial
Genotype
Mutagenesis, Insertional*
Oxidoreductases / biosynthesis,  genetics*,  metabolism
Oxidoreductases Acting on Sulfur Group Donors*
Phenotype
Plasmids
Polymerase Chain Reaction
Recombinant Proteins / biosynthesis,  metabolism
Recombination, Genetic
Restriction Mapping
Substrate Specificity
Sulfites / metabolism
Thiosulfates / metabolism
Chemical
Reg. No./Substance:
0/DNA Primers; 0/Recombinant Proteins; 0/Sulfites; 0/Thiosulfates; EC 1.-/Oxidoreductases; EC 1.8.-/Oxidoreductases Acting on Sulfur Group Donors; EC 1.8.99.2/adenylylsulfate reductase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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