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  • Institute of Physics  (101)
  • Wiley-Blackwell  (18)
  • Blackwell Publishing Ltd  (16)
  • American Geophysical Union  (7)
  • American Association for the Advancement of Science  (5)
  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Annals of public and cooperative economics 51 (1980), S. 0 
    ISSN: 1467-8292
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Wirtschaftswissenschaften
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Annals of public and cooperative economics 51 (1980), S. 0 
    ISSN: 1467-8292
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Wirtschaftswissenschaften
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    ISSN: 1365-2958
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie , Medizin
    Notizen: The Escherichia coli CytR regulator belongs to the LacI family of sequence-specific DNA-binding proteins and prevents CRP-mediated transcription in the CytR regulon. Unlike the other members of this protein family, CytR binds with only modest affinity to its operators and transcription repression thus relies on the formation of nucleoprotein complexes with the cAMP–CRP complex. Moreover, CytR exhibits a rotational and translational flexibility in operator binding that is unprecedented in the LacI family. In this report we examined the effect of changing the spacing between CytR half-operators on CytR regulation in vivo and on CytR binding in vitro. Maximum repression was seen with the short spacing variants: repression peaks when the half-operators lie on the same face of the DNA helix. Repression was retained for most spacing variants with centre separations of half-operators ≤ 3 helical turns. Our data confirm and extend the view that CytR is a highly flexible DNA binder that can adapt many different conformations for co-operative binding with CRP. Furthermore, limited proteolysis of radiolabelled CytR protein showed that the interdomain linker connecting the DNA binding domains and the core part of CytR does not become structured upon DNA binding. We conclude that CytR does not use hinge α-helices for minor groove recognition. Rather, CytR possesses a highly flexible interdomain linker that allows it to form complexes with CRP at promoters with quite different architecture.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 5 (1991), S. 0 
    ISSN: 1365-2958
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie , Medizin
    Notizen: We have studied the doeP2 promoter of Escherichia coli to define features that are required for optimal activation by the complex of adenosine 3′, 5′ monophosphate (cAMP) and the cAMP receptor protein (CRP). Systematic mutagenesis of deoP2 shows that the distance between the CRP site and the -10 hexamer is the crucial factor in determining whether the promoter is activated by camp–CRP. Based on these observations, we propose that camp–CRP-activated promoters can be created by correctly aligning a CRP target and a - 10 hexamer. This idea has been successfully tested by converting both a CRP-in-dependent promoter and a sequence resembling the consensus -10 hexamer to strongly camp–CRP-activated promoters.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1365-2958
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie , Medizin
    Notizen: Unlike classical bacterial repressors, the CytR repressor of Escherichia coli cannot independently regulate gene expression. Here we show that CytR binding to the deoP2 promoter relies on interaction with the master gene regulatory protein, CRP, and, furthermore, that cAMP-CRP and CytR bind co-operatively to deoP2. Using mutant promoters we show that tandem, properly spaced DNA-bound cAMP-CRP complexes are required for this co-operative binding. These data suggest that CytR forms a bridge between tandem cAMP-CRP complexes, and that cAMP-CRP ftjnctions as an adaptor for CytR. The implications of this new version of negative control in E. coli on bacterial gene expression and on combinatorial gene regulation in higher organisms are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    ISSN: 1365-2958
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie , Medizin
    Notizen: We have studied the deoP2 promoter in Escherichia coli to define features important for its interaction with the CytR repressor. As is characteristic for CytR-regulated promoters, deoP2 encodes tandem binding sites for the activating complex cAMP-CRP. One of these sites, CRP-1, overlaps the - 35 region, and is sufficient for activation; the second site, CRP-2, centred around-93, is indispensable for repression. Here we demonstrate, by means of in vivo titration, that CytR interaction with deoP2 depends not only on CRP-2, but also on CRP-1 and the length and possibly the sequence separating these two sites. Also, point mutations in either CRP site reduce or abolish CytR titration; however, no co-operativity is observed in the interaction of CytR with the two CRP binding sites. Furthermore, the reduction in CytR titration parallels the reduction in binding of cAMP-CRP to the mutated CRP sites in vitro. These observations are not easily explained by current models for the action of prokaryotic repressors; instead we favour a model in which the interaction of CytR with deoP2 depends on the presence of tandem DNA-bound cAMP–CRP complexes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 4 (1990), S. 0 
    ISSN: 1365-2958
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie , Medizin
    Notizen: The Escherichia coli cytR-encoded repressor protein (CytR) controls the expression of several genes involved in nucleoside and deoxynucleoside uptake and metabolism. The cytR promoter was identified by determining the transcriptional initiation site of the cytR gene. A chromosomal cytR-lacZ+ operon fusion was isolated and used to study the regulation of cytR. We show that cytR expression is negatively controlled by the CytR protein and positively affected by the cAMP/CAP complex. Foot printing studies with purified CAP protein revealed two CAP binding sites upstream of the cytR promoter. A previousty described mutation (cytR*) in the cloned cytR gene, which results in the phenotypic suppression of a CytR operator mutation in the tsx P2 promoter, was analysed. DN A sequence analysis of the cytR* mutation revealed a G-C to an A-T base pair transition at position -34 bp relative to the translational initiation site of cytR. This point mutation activates a cryptic promoter that is stronger than the wild-type cytR promoter and leads to overproduction of the CytR repressor.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 3 (1989), S. 0 
    ISSN: 1365-2958
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie , Medizin
    Notizen: Transcriptional regulation of the deoP2 promoter by the cyclic AMP/cyclic AMP receptor protein complex (cAMP/CRP) and the CytR repressor requires two high-affinity CRP targets located around -41 and -93 bp preceding the start site for transcription. Here we report the structure of cddP, another CRP/CytR-regulated promoter. In common with what was found in deo, the cdd promoter also contains multiple CRP targets. Thus, using the DNasel footprinting procedure, tandem CRP binding sites were identified around -41 and -93. These findings support a general model for CytR binding and CytR regulation, in which (i) CytR and the CRP/cAMP complex bind to similar or Identical targets, (ii) two or more targets are necessary for proper binding of CytR to a promoter region, and (iii) CytR represses transcription by antagonizing cAMP/CRP activation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 43 (1978), S. 0 
    ISSN: 1750-3841
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Growth stimulation of B. bifidum var. pennsylvanicus by filter- sterilized, unheated amino sugars was studied utilizing an ATCC medium 76 assay system. The order of stimulatory effect was N-acetylglu- cosamine (GlcNAc) 〉 N-acetylgalactosamine 〉 N-acetylmannosamine 〉 N-acetylneuraminic acid. When GlcNAc was heated at 121°C for 15, 30 and 45 min, depression of growth occurred and was directly related to the heat treatment applied. The presence of E. coli B organisms in the assay system did not influence the growth stimulatory effect of the amino sugars on B. bifidum Spent broth, prepared by growth of E. coli B in the assay medium followed by filter sterilization, was found to stimulate the subsequent growth of B. bifidum. The spent broth contained small quantities of amino sugars. E. coli B failed to grow in spent broth prepared from B. bifidum without pH adjustment. Growth of E. coli B was observed when this spent medium was neutralized and fortified with amino sugars, however, without any specific stimulatory pattern attributable to the type of amino sugar.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 42 (1977), S. 0 
    ISSN: 1750-3841
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: In the process of isolating sialic acid from bovine isoelectric casein a hydrolytic product (CBF) was obtained, possessing growth promoting activity for Bifidobacterium bifidum var. pennsylvanicus. Growth was measured turbidimetrically by addition of CBF (250 ppm) to ATCC Medium 76. Stimulation by CBF was comparable to that obtained with N-acetylglucosamine. Whole casein, sialic acid-free casein and k-casein failed -to stimulate the growth of -the organism to the level achieved with CBF. The CBFfraction contained 0.15% nhosohorus. 7% free lactose and various peptides. No sialic acid or ofher amino sugars were detected. On the basis of phosphorus content and amino acid analysis it was concluded that CBF was likely a degradation product of k-casein.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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