Journal ArticleDOI
Release of periplasmic enzymes and other physiological effects of β‐lactamase overproduction in Escherichia coli
TLDR
When Escherichia coli containing the plasmid ptac11 is induced with 10−4 M isopropyl‐β‐thiogalactopyranoside (IPTG), 90% of the β‐lactamase activity of an overnight culture is present in the medium and the level of two membrane proteins, OmpA and OmpC, is decreased.Abstract:
When Escherichia coli containing the plasmid ptac11 is induced with 10(-4) M isopropyl-beta-thiogalactopyranoside (IPTG), 90% of the beta-lactamase activity of an overnight culture is present in the medium. The high extracellular activity of beta-lactamase does not result from cell lysis but from an increase in the permeability of the outer membrane. The excreting cells release several other periplasmic enzymes into the extracellular fluid and are more sensitive to lysis by detergents. It was also shown that in these cells the level of two membrane proteins, OmpA and OmpC, is decreased. None of these phenomena were observed with the plasmid pDW17, which has a mutation in the tac promoter that reduces its activity to one fourth of the tac promoter.read more
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Metabolic load and heterologous gene expression
TL;DR: In this review the physiological changes to host cells, the causes of the phenomenon of metabolic load, and several strategies to avoid some of the problems associated with metabolic load are elaborated and discussed.
Journal ArticleDOI
Production of soluble recombinant proteins in bacteria
TL;DR: This review summarizes what is known about why IBs form and ways of increasing the production of soluble protein in bacterial systems and discusses possibilities for mimicking these mechanisms in bacteria via secretion, cloning of mammalian foldases, and mutation of the post-translational modification systems of the host bacteria.
Journal ArticleDOI
Synthesis of three advanced biofuels from ionic liquid-pretreated switchgrass using engineered Escherichia coli
Gregory Bokinsky,Pamela Peralta-Yahya,Pamela Peralta-Yahya,Anthe George,Anthe George,Bradley M. Holmes,Bradley M. Holmes,Eric J. Steen,Eric J. Steen,Jeffrey A. Dietrich,Jeffrey A. Dietrich,Taek Soon Lee,Taek Soon Lee,Danielle Tullman-Ercek,Danielle Tullman-Ercek,Christopher A. Voigt,Blake A. Simmons,Blake A. Simmons,Jay D. Keasling +18 more
TL;DR: The engineered strains express cellulase, xylanase, beta-glucosidase, and xylobiosidase enzymes under control of native E. coli promoters selected to optimize growth on model cellulosic and hemicellulosic substrates and provide an economical route to production of advanced biofuels.
Journal ArticleDOI
Review: optimizing inducer and culture conditions for expression of foreign proteins under the control of the lac promoter.
TL;DR: Factors which influence the expression of foreign proteins in Escherichia coli under the transcriptional control of thelac andtac promoters are examined and conditions for maximizing the production of a foreign protein using this system are discussed.
Journal ArticleDOI
Structure and morphology of protein inclusion bodies in Escherichia coli.
TL;DR: The degree of solubilization of the inclusion bodies in the presence of denaturants and the sensitivity of the aggregated proteins to protease digestion indicated that the differences between cytoplasmic and periplasmic inclusion bodies extend to the conformation of the associated polypeptide chains.
References
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A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding
TL;DR: This assay is very reproducible and rapid with the dye binding process virtually complete in approximately 2 min with good color stability for 1 hr with little or no interference from cations such as sodium or potassium nor from carbohydrates such as sucrose.
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Improved M13 phage cloning vectors and host strains: nucleotide sequences of the M13mp18 and pUC19 vectors
TL;DR: New Escherichia coli host strains have been constructed for the E. coli bacteriophage M13 and the high-copy-number pUC-plasmid cloning vectors and mutations introduced into these strains improve cloning of unmodified DNA and of repetitive sequences.
Journal ArticleDOI
The release of enzymes from Escherichia coli by osmotic shock and during the formation of spheroplasts.
Harold C. Neu,Leon A. Heppel +1 more
TL;DR: A new method for releasing most of the inducible alkaline phosphatases and of the cyclic phosphodiesterase in high yield without greatly impairing the viability of the cells is developed.
Journal ArticleDOI
Vectors bearing a hybrid trp-lac promoter useful for regulated expression of cloned genes in Escherichia coli
TL;DR: The tac promoter is repressed in lacIQ strains and can be induced by isopropylthio-beta-D-galactoside (IPTG), and studies of expression of the cI repressor of bacteriophage lambda show that the tac promoters is at least five times more efficient than the lacUV5 promoter.