Topic
Escherichia coli
About: Escherichia coli is a research topic. Over the lifetime, 59041 publications have been published within this topic receiving 2050337 citations. The topic is also known as: E. coli & E coli jdj.
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TL;DR: This ADP-ribosylating (Al) fragment of the toxin has structural homology with the catalytic region of exotoxin A and hence also to diphtheria toxin.
Abstract: Examination of the structure of Escherichia coli heat-labile enterotoxin in the AB5 complex at a resolution of 2.3 A reveals that the doughnut-shaped B pentamer binds the enzymatic A subunit using a hairpin of the A2 fragment, through a highly charged central pore. Putative ganglioside GM1-binding sites on the B subunits are more than 20 A removed from the membrane-crossing Al subunit. This ADP-ribosylating (Al) fragment of the toxin has structural homology with the catalytic region of exotoxin A and hence also to diphtheria toxin.
537 citations
TL;DR: The current status of the Escherichia coli prokaryotic expression system is described and strategies designed to maximize the yields of recombinant proteins are focused on.
536 citations
TL;DR: The results suggest that indigo formation is due to the combined activities of tryptophanase and naphthalene dioxygenase.
Abstract: A fragment of plasmid NAH7 from Pseudomonas putida PpG7 has been cloned and expressed in Escherichia coli HB101. Growth of the recombinant Escherichia coli in nutrient medium results in the formation of indigo. The production of this dye is increased in the presence of tryptophan or indole. Several bacteria that oxidize aromatic hydrocarbons to cis-dihydrodiols also oxidize indole to indigo. The results suggest that indigo formation is due to the combined activities of tryptophanase and naphthalene dioxygenase.
534 citations
TL;DR: The bacterial superoxide dismutase, which catalyzes the disproportionation of univalently reduced oxygen, has now been purified from Escherichia coli and was found to contain manganese.
534 citations
TL;DR: In vitro analyses with purified enzyme indicated that MAP is a metallo-oligopeptidase with absolute specificity for the amino-terminal methionine, consistent with the deduced specificity of the enzyme based on the analysis of known amino- terminal sequences of intracellular proteins.
Abstract: Methionine aminopeptidase (MAP) catalyzes the removal of amino-terminal methionine from proteins. The Escherichia coli map gene encoding this enzyme was cloned; it consists of 264 codons and encodes a monomeric enzyme of 29,333 daltons. In vitro analyses with purified enzyme indicated that MAP is a metallo-oligopeptidase with absolute specificity for the amino-terminal methionine. The methionine residues from the amino-terminal end of the recombinant proteins interleukin-2 (Met-Ala-Pro-IL-2) and ricin A (Met-Ile-Phe-ricin A) could be removed either in vitro with purified MAP enzyme or in vivo in MAP-hyperproducing strains of E. coli. In vitro analyses of the substrate preference of the E. coli MAP indicated that the residues adjacent to the initiation methionine could significantly influence the methionine cleavage process. This conclusion is consistent, in general, with the deduced specificity of the enzyme based on the analysis of known amino-terminal sequences of intracellular proteins (S. Tsunasawa, J. W. Stewart, and F. Sherman, J. Biol. Chem. 260:5382-5391, 1985).
533 citations