Lactose Carrier Protein of Escherichia coli Structure and Expression of Plasmids Carrying the Y Gene of the lac Operon
Ron M. Teather,John Bramhall,Isolde Riede,J. Keith Wright,Monika Fürst,Gabriele Aichele,Ursula Wilhelm,Peter Overath +7 more
TLDR
Upon induction of pTE18-harbouring strains the Y-gene product is expressed at a nearly constant rate for several generations and accumulates to a level of 12-16% of the total cytoplasmic membrane protein.Abstract:
The previously described hybrid plasmid pC7 which carries lacI+O+delta(Z)Y+A+ on a 12.3 X 10(6)-Mr DNA fragment [Teather et al. (1978) Mol. Gen. Genet. 159, 239-248] was partially digested with the restriction endonuclease EcoRI under conditions reducing the recognition sequence to d(A-A-T-T) and ligated to the vector pB322. lac Y-carrying inserts of various sized (Mr 1.5-4.7 X 10(6)) were obtained. Hybrid plasmid pTE18 (2300-base-pair insert) carries part of the I (repressor) gene, the promotor-operator region, part of the Z (beta-galactosidase) gene, the Y (lactose carrier) gene and part of the A (transacetylase) gene. Upon induction of pTE18-harbouring strains the Y-gene product is expressed at a nearly constant rate for several generations and accumulates to a level of 12-16% of the total cytoplasmic membrane protein. Integration into the membrane leads to active carrier as judged by binding and transport measurements.read more
Citations
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Overexpression of integral membrane proteins for structural studies
TL;DR: Crystallisation of membranes proteins in 3D has led to the determination of four atomic resolution structures and crystals of membrane proteins formed in the plane of the lipid bilayer (2D crystals) have produced two more structures.
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Purification and reconstitution of functional lactose carrier from Escherichia coli.
TL;DR: Results demonstrate that the lactose carrier is the only polypeptide species essential for energy-coupled lactose transport and counterflow and that the purified protein was identified as the product of the lac y gene.
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Protein phosphorylation and allosteric control of inducer exclusion and catabolite repression by the bacterial phosphoenolpyruvate: sugar phosphotransferase system.
TL;DR: A model involving allosteric activation of adenylate cyclase by phospho-IIIGlc, together with the evidence supporting it, is presented and appears likely that the general process of PTS-catalyzed protein phosphorylation-dephosphorylation will be important to the regulation of numerous bacterial physiological processes, including chemotaxis, intermediary metabolism, gene transcription, and virulence.
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Refolding and Oriented Insertion of a Membrane Protein into a Lipid Bilayer
Thomas Surrey,Fritz Jähnig +1 more
TL;DR: This work has studied the refolding and membrane insertion of the outer membrane protein OmpA of Escherichia coli, which spontaneously refolded and inserted into the vesicle membranes.
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Lactose transport system of Streptococcus thermophilus: a hybrid protein with homology to the melibiose carrier and enzyme III of phosphoenolpyruvate-dependent phosphotransferase systems.
TL;DR: A 4.2-kilobase fragment from an EcoRI library of chromosomal DNA was cloned in Escherichia coli by using the vector pKK223-3 as discussed by the authors.
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