Mutants of Salmonella typhimurium Able to Utilize d -Histidine as a Source of l -Histidine
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چکیده
منابع مشابه
Histidine Regulatory Mutants in Salmonella typhimurium
Regulation of the histidine operon in Salmonella typhimurium has been shown to involve at least six separate genes (Roth, Antdn & Hartman, 1966; Ant&, 1968). Mutations in any one of these separate genes can destroy the ability of the cell to repress fully the histidine biosynthetic enzymes. In order to understand this regulatory mechanism and the nature of these mutations, we have studied the d...
متن کاملHistidine regulatory mutants in Salmonella typhimurium II. Histidine regulatory mutants having altered histidyl-tRNA synthetase.
(1) The hid’ gene of Salmonelb ty(phinzurium is the structural gene for histidyltRNA synthetase. Mutants in the hid gene have an altered histidyl-tRNA synthetase and constitute one of the four classes of histidine regulatory mutants. (2) Mutant hisS1520 has a synthetase with a 60.fold decreased affinity for histidine. This mutant has a markedly decreased growth rate on minimal medium and is de-...
متن کاملHistidine regulation in Salmonella typhimurium. IX. Histidine transfer ribonucleic acid of the regulatory mutants.
Four classes of mutants constitutive for the histidine operon of Salmonella iyphimurium, hisR, hisT, hisU, and hisW, were examined for a possible role in the production of histidine tRNA. The content of tRNAHi” in tRNA isolated from each of the mutant types was compared to that of the wild type, and the chromatographic behavior of the tRNAHiB obtained from the mutants and the wild type was exam...
متن کاملHistidine regulation in Salmonella typhimurium. XV. Procedure for the selection of mutants unable to derepress the histidine operon.
A general search has been made for mutants defective in their ability to derepress the histidine operon. The procedure was to select for mutants with an increased sensitivity to the false feedback inhibitor, 2-thiazolealanine. Five mutant strains defective in derepression have been isolated. All five strains are unable to derepress normally because of mutations located in the operator-promoter ...
متن کاملHISTIDINE MUTANTS REQUIRING ADENINE: SELECTION OF MUTANTS WITH REDUCED hisG EXPRESSION IN SALMONELLA TYPHIMURIUM H
A method is described for the selection of Salmonella typhimurium mutants with reduced levels of hisG enzyme activity. This method is based on the fact that the hisG enzyme catalyzes the consumption of ATP in the first step of histidine biosynthesis. Normally, this reaction is closely regulated, both by feedback inhibition and by repression of the operon. However, conditions can be set up that ...
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ژورنال
عنوان ژورنال: Journal of Bacteriology
سال: 1971
ISSN: 0021-9193,1098-5530
DOI: 10.1128/jb.105.1.28-37.1971