Analysis of theEscherichia coli proBAlocus by DNA and protein sequencing

Abstract

A 2.9 kb DNA fragment carrying the Escherichia coli proBA region, which encodes the first two enzymes of the proline biosynthetic pathway, was subcloned onto an expression plasmid carrying both the bacteriophage lambda PL promoter (lambda PL) and the lambda gene encoding a thermolabile cI repressor protein (cI857). Derepression of the lambda PL promoter by thermal inactivation of the cI857 repressor protein resulted in the simultaneous overproduction of the proB (gamma-glutamyl kinase) and proA (gamma-glutamyl phosphate reductase) gene products. Nucleotide sequence analysis of the proBA locus allowed gene assignments consistent with the NH2 and COOH-terminal analyses and amino acid compositions of homogeneous preparations of the proB and proA proteins. The contiguous nature of the proB and proA genes suggests that the two genes constitute an operon in which proB precedes proA.

Neutrino Mass Constraints onβDecay

“…Our limitā RL < 10 −2 is comparable to the present experimental limit from β decayā RL < 3.7 × 10 −2 [13] (see also Ref. [1]).…”

Isolation, characterization, and chromosomal location of a gene encoding the Δ1‐pyrroline‐5‐carboxylate synthetase in Arabidopsis thaliana

“…In eubacteria, ~'-glutamyl kinase and T-glutamyl phosphate reductase which are encoded by the proBA operon form a multimolecular complex allowing a direct and protected transfer of the very labile ~,-glutamyl phosphate intermediate [13,14,30]. Interestingly in yeast, ?…”

“…To identify A. thaliana P5C synthetase cDNA(s), degenerate oligonucleotide primers in conserved sequences between P5CS cDNA from V aconitifolia [8], proB and proA sequences from E. eoli [13] and Serratia marcescens [14] (primer 1 = 5'-ATWGCYGATGCCCTKGAAGC-AAA-3'; primer 2 --5'-TCWSWGAATCTKGTGCTKGCRTT-3') were used in polymerase chain reactions (PCR) to amplify a DNA tYagment from genomic DNA ofA. thaliana ecotype Columbia.…”

“…Sequence comparison with the databases were performed using BLAST through the NCBI E-mail server [18]. Protein secondary structure analysis was determined by using the PredictProtein program (EMBL Heidelberg, Germany) [19,20] with multiple sequence alignments of the seven proteins showing highest similarity, P5CS from V. aconitifolia [8], y-glutamyl kinase and y-glutamyl phosphate reductase from E. coli [13], S. marcescens [14] and Bacillus subtilis [21]. Inclusion of protein homologs increases the prediction accuracy of the secondary structure to 70% [19].…”

Analysis of the Serratia marcescens proBA operon and feedback control of proline biosynthesis

“…We used S. marcescens TT392 containing the high-copy-number proBA recombinant plasmid, pWP142, to measure the proline-inhibitable GK activity. L-Proline completely inhibited the activity at concentrations greater than 0.04 mM and inhibited it by 50% at 0.016 mM (the absolute value corresponding to Deutch et al, 1984;Csonka et al, 1988) are presented in the one-letter code. Identical residues are indicated by boxed regions.…”