A new suite of tnaA mutants suggests that Escherichia coli tryptophanase is regulated by intracellular sequestration and by occlusion of its active site.

ABSTRACT:

Background

The Escherichia coli enzyme tryptophanase (TnaA) converts tryptophan to indole, which triggers physiological changes and regulates interactions between bacteria and their mammalian hosts. Tryptophanase production is induced by external tryptophan, but the activity of TnaA is also regulated by other, more poorly understood mechanisms. For example, the enzyme accumulates as a spherical inclusion (focus) at midcell or at one pole, but how or why this localization occurs is unknown.

Results

TnaA activity is low when the protein forms foci during mid-logarithmic growth but its activity increases as the protein becomes more diffuse, suggesting that foci may represent clusters of inactive (or less active) enzyme. To determine what protein characteristics might mediate th

SUBMITTER: Li G 

PROVIDER: S-EPMC4323232 | biostudies-literature | 2015 Feb

REPOSITORIES: biostudies-literature