D-histidine utilization in Salmonella typhimurium is controlled by the leucine-responsive regulatory protein (Lrp).

AUTOR(ES)

Hecht, K

RESUMO

A new class of D-histidine-utilizing mutants which carry mutations in the gene encoding the leucine-responsive regulatory protein (Lrp) has been identified in Salmonella typhimurium. The lrp mutations arise as suppressors of mutations in the genes encoding the histidine permease which drastically decrease the level of histidine transport activity. However, the suppressor effect is not exerted by elevating the level of the permease. Rather, the properties of the suppressor mutants are consistent with the notion that the parent permease mutants transport D-histidine at a low level and that in the suppressor mutants D-histidine is utilized effectively through elevated levels of racemization. The enzymatic activity of D-alanine dehydrogenase (Dad) is shown to be elevated in the suppressor mutants and is a possible pathway of D-histidine utilization. The suppressor mutations are located in the helix-turn-helix region of Lrp.

Documentos Relacionados

• Characterization of the regulon controlled by the leucine-responsive regulatory protein in Escherichia coli.
• A Pyrococcus homolog of the leucine-responsive regulatory protein, LrpA, inhibits transcription by abrogating RNA polymerase recruitment
• Use of an inducible regulatory protein to identify members of a regulon: application to the regulon controlled by the leucine-responsive regulatory protein (Lrp) in Escherichia coli.
• Mutants of Salmonella typhimurium Able to Utilize d-Histidine as a Source of l-Histidine
• The leucine-responsive regulatory protein, a global regulator of metabolism in Escherichia coli.