title: A large decrease in heat-shock-induced proteolysis after tryptophan starvation leads to increased expression of phage lambda lysozyme cloned in Escherichia coli.
abstract: The R gene coding for phage lambda lysozyme (lambda L), cloned under the control of the PL promoter on a multicopy vector, is expressed in an Escherichia coli strain auxotrophic for tryptophan. Induction by a thermal shift after tryptophan supplementation in a culture initially brought into stationary phase by tryptophan starvation leads to highly increased expression. A thermally unstable mutant protein, difficult to obtain under standard conditions, can be easily produced by post-stationary-phase expression. It is shown that this is due to a drastic decrease in the heat-shock-induced proteolysis normally observed on thermal induction. These data are discussed in relation to our present knowledge of stringent and heat-shock responses.
authors.affiliation: Laboratoire de Biochimie Physique et des Biopolymères, Université Catholique de Louvain, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Soumillion
authors.forename: J
authors.initials: J
authors.lastname: Fastrez
mesh_terms: D010582:Bacteriophage lambda / Q000201:enzymology* / Q000235:genetics*; D002701:Chloramphenicol / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006358:Hot Temperature; D007700:Kinetics; D009113:Muramidase / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D013696:Temperature; D014364:Tryptophan / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D002701:Chloramphenicol; D014364:Tryptophan; D009113:Muramidase