Isolation and characterization of an Escherichia coli mutant having temperature-sensitive farnesyl diphosphate synthase. |
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| Authors: | S Fujisaki T Nishino H Katsuki H Hara Y Nishimura Y Hirota |
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| Affiliation: | Department of Chemistry, Faculty of General Education, Gifu University, Japan. |
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| Abstract: | The screening of a collection of highly mutagenized strains of Escherichia coli for defects in isoprenoid synthesis led to the isolation of a mutant that had temperature-sensitive farnesyl diphosphate synthase. The defective gene, named ispA, was mapped at about min 10 on the E. coli chromosome, and the gene order was shown to be tsx-ispA-lon. The mutant ispA gene was transferred to the E. coli strain with a defined genetic background by P1 transduction for investigation of its function. The in vitro activity of farnesyl diphosphate synthase of the mutant was 21% of that of the wild-type strain at 30 degrees C and 5% of that at 40 degrees C. At 42 degrees C the ubiquinone level was lower (66% of normal) in the mutant than in the wild-type strain, whereas at 30 degrees C the level in the mutant was almost equal to that in the wild-type strain. The polyprenyl phosphate level was slightly higher in the mutant than in the wild-type strain at 30 degrees C and almost the same in both strains at 42 degrees C. The mutant had no obvious phenotype regarding its growth properties. |
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