Abstract
A mutant of Escherichia coli harboring a temperature-labile phosphoribosylpyrophosphate (PRPP) synthetase was characterized. Despite the lack of a detectable PRPP pool or PRPP synthetase activity at 40 degrees C, the strain was fully viable at this temperature as long as guanosine, uridine, histidine, tryptophan, and nicotinamide mononucleotide were all added to the growth medium. Viability of the strain was dependent upon mutations in genes of the nucleoside salvage pathways that improved the utilization of exogenous nucleosides. The properties of the strain are those expected of a PRPP-less strain and suggest that PRPP synthetase is dispensable for E. coli.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Escherichia coli / genetics*
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Escherichia coli / growth & development
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Escherichia coli / metabolism
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Histidine / metabolism*
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Mutation
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NAD / metabolism*
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Phosphoribosyl Pyrophosphate / metabolism
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Phosphotransferases (Alcohol Group Acceptor)*
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Phosphotransferases / genetics*
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Purine Nucleosides / metabolism*
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Purine-Nucleoside Phosphorylase / genetics
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Pyrimidine Nucleosides / metabolism*
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Ribose-Phosphate Pyrophosphokinase / genetics*
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Tryptophan / metabolism*
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Uridine Phosphorylase / genetics
Substances
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Purine Nucleosides
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Pyrimidine Nucleosides
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NAD
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Histidine
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Phosphoribosyl Pyrophosphate
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Tryptophan
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Purine-Nucleoside Phosphorylase
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Uridine Phosphorylase
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Phosphotransferases
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Phosphotransferases (Alcohol Group Acceptor)
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guanosine kinase
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Ribose-Phosphate Pyrophosphokinase