Control of Expression of the
            <scp>l</scp>
            -Arabinose Operon in Temperature-Sensitive Mutants of Gene
            <i>araC</i>
            in
            <i>Escherichia coli</i>
            B/r

Irr, Joseph; Englesberg, Ellis

doi:10.1128/jb.105.1.136-141.1971

Cited by 9 publications

(5 citation statements)

References 11 publications

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“…Upon the binding of arabinose most of the protein shifts and instead, binds to the adjacent direct repeat DNA half‐sites I 1 and I 2 , (Fig. ) where it actively stimulates transcription . Arabinose does not appear to shift the relative affinities in binding to the similar, but nonidentical DNA half‐sites involved.…”

Section: Introductionmentioning

confidence: 96%

A genetic and physical study of the interdomain linker ofE. ColiAraC protein-atrans-subunit communication pathway

et al. 2016

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Genetic experiments with full length AraC and biophysical experiments with its dimerization domain plus linker suggest that arabinose binding to the dimerization domain changes the properties of the inter-domain linker which connects the dimerization domain to the DNA binding domain via interactions that do not depend on the DNA binding domain. Normal AraC function was found to tolerate considerable linker sequence alteration excepting proline substitutions. The proline substitutions partially activate transcription even in the absence of arabinose and hint that a structural shift between helix and coil may be involved. To permit fluorescence anisotropy measurements that could detect arabinose-dependent dynamic differences in the linkers, IAEDANS was conjugated to a cysteine residue substituted at the end of the linker of dimerization domain. Arabinose, but not other sugars, decreased the steady-state anisotropy, indicating either an increase in mobility and/or an increase in the fluorescence lifetime of the IAEDANS. Time-resolved fluorescence measurements showed that the arabinose-induced anisotropy decrease did not result from an increase in the excited-state lifetime. Hence arabinose-induced decreases in anisotropy appear to result from increased tumbling of the fluorophore. Arabinose did not decrease the anisotropy in mutants incapable of binding arabinose nor did it alter the anisotropy when IAEDANS was conjugated elsewhere in the dimerization domain. Experiments with heterodimers of the dimerization domain showed that the binding of arabinose to one subunit of the dimer decreases the fluorescence anisotropy of only a fluorophore on the linker of the other subunit.

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Section: Introductionmentioning

confidence: 96%

A genetic and physical study of the interdomain linker ofE. ColiAraC protein-atrans-subunit communication pathway

et al. 2016

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“…Capacity levels were also determined in a temperature-sensitive mutant that maps in the regulatory gene of the arabinose operon. This is mutant araC42 which produces a functional, positively acting, regulatory gene protein at 28 C but lacks this activity at 42 C (9). In this strain, isomerase capacity rapidly decayed during growth at 42 C, indicating that no new mRNA was being synthesized at this temperature because of the thermolability of the regulatory gene protein.…”

Section: Resultsmentioning

confidence: 97%

“…All bacterial strains used are derivatives of E. coli B/r, and their pertinent genotypes are shown in Table 1. The composition of all culture media was described previously (9). Abbreviations for culture media are: AL, minimal L-arabinose (0.2%) supplemented with Lleucine (40 mg/liter); MA, minimal L-arabinose; EMB, Levine eosin methylene blue agar without lactose and supplemented with L-arabinose (1.0%); CAA, minimal base plus Casamino Acids (1.0%).…”

mentioning

confidence: 99%

l -Arabinose Isomerase Formation in a Conditional Mutant of Gene araA of Escherichia coli B/r

1972

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A temperature-sensitive mutant of Escherichia coli in which the synthesis of l -arabinose isomerase is blocked during growth at 42 C was found to possess the following properties. (i) The mutation occurred in the structural gene for the isomerase, gene araA . (ii) During growth at elevated temperatures the mutant accumulates a product which is a precursor to the active enzyme. (iii) The precursor produced at 42 C is slowly converted to active enzyme at 28 C in the absence of protein and ribonucleic acid synthesis. It is concluded that the mutation results in a change in the structure of isomerase which causes formation of active enzyme to be thermolabile at a step beyond the level of translation.

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“…An additional discrepancy is the lack of temperature-sensitive pleiotropic mutants in this system. Irr and Englesberg (6) found that a high proportion of araCmutants are able to grow with arabinose at low temperature and thus are temperature-sensitive. Furthermore, an araCmutant was found to yield temperature-sensitive revertants if selected for reversion at low temperature.…”

Section: Discussionmentioning

confidence: 99%

Genetic Control of Enzyme Induction in the β-Ketoadipate Pathway ofPseudomonas putida:Deletion Mapping ofcatMutations

Wheelis

Ornston

1972

J Bacteriol

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A number of spontaneous mutant strains of Pseudomonas putida, obtained by repeated selection for inability to grow with cis,cis-muconate, have been shown to carry deletions in catB, the structural gene for muconate lactonizing enzyme. These strains have been employed for deletion mapping of the genetic region containing catB and catC (the structural gene for muconolactone isomerase, the synthesis of which is coordinate with that of muconate lactonizing enzyme). All deletions that overlap mutant sites located on the left side of the genetic map, as well as the point mutations in that region, lead to a pleiotropic loss of both catB and catC activities. We propose that this region to the left of catB has a regulatory function. Although the details of regulation at the molecular level are unclear, our data indicate that catB and catC may well be controlled by a mechanism unlike any yet described by workers on enteric bacteria.

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Control of Expression of the l -Arabinose Operon in Temperature-Sensitive Mutants of Gene araC in Escherichia coli B/r

Cited by 9 publications

References 11 publications

A genetic and physical study of the interdomain linker ofE. ColiAraC protein-atrans-subunit communication pathway

A genetic and physical study of the interdomain linker ofE. ColiAraC protein-atrans-subunit communication pathway

l -Arabinose Isomerase Formation in a Conditional Mutant of Gene araA of Escherichia coli B/r

Genetic Control of Enzyme Induction in the β-Ketoadipate Pathway ofPseudomonas putida:Deletion Mapping ofcatMutations

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