Specificity of the induction of the enzymes of the lac operon in Escherichia coli

Müller‐Hill, Benno; Rickenberg, H.V.; Wallenfels, Kurt

doi:10.1016/s0022-2836(64)80049-8

Cited by 128 publications

(48 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Phytase production increased dramatically after 4 h of induction. Delay in enzyme production on lactose induction during fed-batch cultivation of E. coli BL21(DE3) cells has been reported earlier [32,42] and could be explained by the time needed for lactose to be processed to allolactose, an inducer for lac UV5 in E. coli chromosome and lac o in pET-22b(+) [11,25].…”

Section: Production Of the Recombinant Phytase By Fed-batch Cultivatimentioning

confidence: 63%

A thermostable phytase from Bacillus sp. MD2: cloning, expression and high-level production in Escherichia coli

Tran

Mamo

Mattìasson

et al. 2009

J Ind Microbiol Biotechnol

View full text Add to dashboard Cite

Phytase is used as a feed additive for degradation of antinutritional phytate, and the enzyme is desired to be highly thermostable for it to withstand feed formulation conditions. A Bacillus sp. MD2 showing phytase activity was isolated, and the phytase encoding gene was cloned and expressed in Escherichia coli. The recombinant phytase exhibited high stability at temperatures up to 100 degrees C. A higher enzyme activity was obtained when the gene expression was done in the presence of calcium chloride. Production of the enzyme by batch- and fed-batch cultivation in a bioreactor was studied. In batch cultivation, maintaining dissolved oxygen at 20-30% saturation and depleting inorganic phosphate below 1 mM prior to induction by IPTG resulted in over 10 U/ml phytase activity. For fed-batch cultivation, glucose concentration was maintained at 2-3 g/l, and the phytase expression was increased to 327 U/ml. Induction using lactose during fed-batch cultivation showed a lag phase of 4 h prior to an increase in the phytase activity to 71 U/ml during the same period as IPTG-induced production. Up to 90% of the total amount of expressed phytase leaked out from the E. coli cells in both IPTG- and lactose-induced fed-batch cultivations.

show abstract

Section: Production Of the Recombinant Phytase By Fed-batch Cultivatimentioning

confidence: 63%

A thermostable phytase from Bacillus sp. MD2: cloning, expression and high-level production in Escherichia coli

Tran

Mamo

Mattìasson

et al. 2009

J Ind Microbiol Biotechnol

View full text Add to dashboard Cite

show abstract

“…Alcohol dehydrogenase [2] Bacteria dehydrogenase 131 L-Amino oxidase [4] Xanthine oxidase [S, 61 nunsferases Phosphorylase 171 Levan saccharase [8] Hydroluses Acetylcholinesterase [9] Lipase [lo, 111 Trypsin [I 11…”

Section: Onidoreductasesmentioning

confidence: 99%

The Anomalous Temperature Dependence of Enzyme‐Catalyzed Reactions

Talsky¹

1971

Angew. Chem. Int. Ed. Engl.

View full text Add to dashboard Cite

Breaks or curvatures in the plot of log vbr us. IIT have been described in the literature for a number of reactions. If sufficiently small temperature intervals are used in the investigation of the temperature dependence (STI method) a trend line is obtained instead. It is then possible to distinguish regions of linear behavior and regions of anomalous behavior. The effects of e. g . the p H , the ionic strength, and added salts as well as of the size of the enzyme and substrate molecules on the anamalies were examined. The anomalous temperature dependence of the reaction rate was found to be a particularly sensitive indicator of the reaction event on the enzyme. The course of the reaction is evidently affected even by relatively small changes in conformation, particularly in the region of the active center

show abstract

“…7 Some of these compounds were able to mimic the natural inducer allolactose, while others bound but failed to induce, indicating that binding to the repressor was not sufficient to cause the allosteric response. [8][9][10][11] MullerHill extended the list of effector molecules and classified them as inducers or anti-inducers based upon how they modulated bacterial growth, 8 and Riggs performed extensive in vitro binding assays in an attempt to understand how a group of chemically similar compounds could produce such distinct phenotypes. 11 A classification scheme arose whereby effectors were defined as inducers when the binding lowered the repressor's affinity for the operator and as anti-inducers when their binding stabilized the repressor-operator complex.…”

Section: Introductionmentioning

confidence: 99%

Structural Analysis of Lac Repressor Bound to Allosteric Effectors

Daber

Stayrook

Rosenberg

et al. 2007

Journal of Molecular Biology

122

View full text Add to dashboard Cite

The lac operon is a model system for understanding how effector molecules regulate transcription and are necessary for allosteric transitions. The crystal structures of the lac repressor bound to inducer and anti-inducer molecules provide a model for how these small molecules can modulate repressor function. The structures of the apo repressor and the repressor bound to effector molecules are compared in atomic detail. All effectors examined here bind to the repressor in the same location and are anchored to the repressor through hydrogen bonds to several hydroxyl groups of the sugar ring. Inducer molecules form a more extensive hydrogen-bonding network compared to anti-inducers and neutral effector molecules. The structures of these effector molecules suggest that the O6 hydroxyl on the galactoside is essential for establishing a water-mediated hydrogen bonding network that bridges the N-terminal and C-terminal sub-domains. The altered hydrogen bonding can account in part for the different structural conformations of the repressor, and is vital for the allosteric transition.

show abstract

Specificity of the induction of the enzymes of the lac operon in Escherichia coli

Cited by 128 publications

References 17 publications

A thermostable phytase from Bacillus sp. MD2: cloning, expression and high-level production in Escherichia coli

A thermostable phytase from Bacillus sp. MD2: cloning, expression and high-level production in Escherichia coli

The Anomalous Temperature Dependence of Enzyme‐Catalyzed Reactions

Structural Analysis of Lac Repressor Bound to Allosteric Effectors

Contact Info

Product

Resources

About