title: Characterization of a mycothiol ligase mutant of Rhodococcus jostii RHA1.
abstract: Mycothiol (1d-myo-inosityl 2-[N-acetyl-L-cysteinyl]amido-2-deoxy-alpha-D-glucopyranoside) is an important microbial thiol present only in actinomycetes. Rhodococcus jostii RHA1 degrades a wide range of xenobiotics, including polychlorinated biphenyls, nitriles and N-nitrosodimethylamine. Analyses revealed that this strain produces two thiols, mycothiol and ergothioneine, found in the other actinomycetes. A mycothiol ligase mutant strain of R. jostii RHA1 deficient in the production of mycothiol was constructed. This mutant has a number of interesting characteristics: (a) it overproduces the intermediate glucosamine-inositol (1-O-(2-amino-1-deoxy-alpha-D-glucopyranosyl)-D-myo-inositol); (b) it is deficient in the biochemical degradation of a number of xenobiotics metabolized by the parent strain; (c) it shows increased susceptibility to a number of antibiotics; and (d) it shows unusual growth characteristics, exhibiting a long lag phase before normal exponential growth. The diverse phenotypes of the mutant indicate the utility of R. jostii RHA1 as a model for deciphering the various functions of mycothiol.
authors.affiliation: Department of Microbiology and Immunology, Life Sciences Institute, 2350 Health Sciences Mall, University of British Columbia, Vancouver, BC V6T 1Z3, Canada. manishad@interchange.ubc.ca
authors.forename: Manisha
authors.initials: M
authors.lastname: Dosanjh
authors.forename: Gerald L
authors.initials: GL
authors.lastname: Newton
authors.forename: Julian
authors.initials: J
authors.lastname: Davies
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003470:Culture Media; D003545:Cysteine / Q000378:metabolism*; D004880:Ergothioneine / Q000378:metabolism; D017353:Gene Deletion; D005944:Glucosamine / Q000378:metabolism; D006020:Glycopeptides / Q000378:metabolism*; D007294:Inositol / Q000378:metabolism*; D008025:Ligases / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D012240:Rhodococcus / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D006020:Glycopeptides; C089265:mycothiol; D007294:Inositol; D004880:Ergothioneine; D008025:Ligases; D003545:Cysteine; D005944:Glucosamine