Gram-negative bacteria export a large variety of antimicrobial compounds by forming two-membrane spanning tripartite multidrug efflux systems composed an inner membrane transporter, outer channel and periplasmic adaptor protein. Here we present the co-expression, purification first electron microscopy insights Escherichia coli EmrAB–TolC Major Facilitator Superfamily (MSF) system as whole compl...

The vanE operon was characterized from Enterococcus faecalis N00-410 (MIC of vancomycin = 24 microg/ml). The organization of the vanE operon was identical to that of the vanC1 operon from Enterococcus gallinarum, with protein identities ranging from 46 to 63%. An open reading frame located downstream of the vanE operon showed significant homology to a number of integrase genes, all of which are...

We predict the operon structure of the Bacillus subtilis genome using the average operon length, the distance between genes in base pairs, and the similarity in gene expression measured in time course and gene disruptant experiments. By expressing the operon prediction for each method as a Bayesian probability, we are able to combine the four prediction methods into a Bayesian classifier in a s...

This article presents evidence that starvation for leucine in an Escherichia coli auxotroph triggers metabolic activities that specifically target the leu operon for derepression, increased rates of transcription, and mutation. Derepression of the leu operon was a prerequisite for its activation by the signal nucleotide, guanosine tetraphosphate, which accumulates in response to nutritional str...

BACKGROUND In an effort to identify alternate recombinant gene expression systems in Pseudomonas fluorescens, we identified genes encoding two native metabolic pathways that were inducible with inexpensive compounds: the anthranilate operon (antABC) and the benzoate operon (benABCD). RESULTS The antABC and benABCD operons were identified by homology to the Acinetobacter sp. anthranilate opero...

‘IIN trpA gene product was analyzed from a class of strains of Escherichia coli I112 in which the lac operon has been fused by deletion t,o the trp operon. These are strains that have retained the ability to synthesize tryptophan. Two of these strains are shown to make a wild-type trpA product ; these strains retain intact all structural genes of the trp operon. It is proposed that the lac oper...

Bistability in the lac operon of Escherichia coli has been widely studied, both experimentally and theoretically. Experimentally, bistability has been observed when E. coli is induced by an artificial, nonmetabolizable, inducer. However, if the lac operon is induced with lactose, the natural inducer, bistability has not been demonstrated. We derive an analytical expression that can predict the ...

The abilities of 14 tryptophan analogs to repress the tryptophan (trp) operon have been studied in Escherichia coli cells derepressed by incubation with 0.25 mM indole-3-propionic acid (IPA). trp operon expression was monitored by measuring the specific activities of anthranilate synthase (EC 4.1.3.27) and the tryptophan synthase (EC 4.2.1.20) beta subunit. Analogs characterized by modification...