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A novel function of the cAMP-CRP complex in Escherichia coli: cAMP-CRP functions as an adaptor for the CytR repressor in the deo operon 总被引:4,自引:0,他引:4
L. Søgaard-Andersen H. Pedersen B. Hoist P. Valentin-Hansen 《Molecular microbiology》1991,5(4):969-975
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 functions 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. 相似文献
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Johan Gottfries Pam Fredman Jan-Eric Mansson V. Peter Collins Hans von Hoist † Dawna D. Armstrong ‡ Alan K. Percy § Carol J. Wikstrand Darell D. Bigner Lars Svennerholm 《Journal of neurochemistry》1990,55(4):1322-1326
The ganglioside composition of six human medulloblastomas was analyzed. The characterization was performed by thin-layer chromatography, sialidase hydrolysis, and immunological staining with a panel of characterized antiganglioside monoclonal antibodies. The total ganglioside content ranged from 60 to 1,130 nmol of ganglioside sialic acid/g wet weight. Neuronal gangliosides (gangliotetraose series) were found in varying amounts in all medulloblastomas. Gangliosides of the neolactotetraose series (3'-LM1 and LD1) were present in all specimens, and the lactotetraose series ganglioside 3'-isoLM1 was found in all cases showing astrocytic differentiation. This supports our previous findings that 3'-isoLM1 is a marker for proliferating astroglial cells. 相似文献
3.
Pam Fredman Hans von Hoist V. Peter Collins† Lars Granholm Lars Svennerholm 《Journal of neurochemistry》1988,50(3):912-919
The ganglioside composition of surgically removed human glioma tissue was shown to differ from that of normal adult brain tissue. First, it contained reduced amounts of the major normal brain gangliosides of the gangliotetraose series. Second, it contained increased proportions of gangliosides not detected in normal brain tissue. One of these was isolated and established as being sialyllactotetraosylceramide 3'-isoLM1. Radioimmunoassay for this ganglioside antigen in human glioma tissue revealed that 14/14 specimens of grades III and IV were positive but only 1/4 of grade II. Normal brain tissue was negative. These results suggest that sialyllactotetraosylceramide is a marker for human malignant gliomas. 相似文献
4.
Tsutomu Arakawa Paige Hoist Linda O. Narhi John S. Philo Jie Wen Steven J. Prestrelski Xiaotian Zhu Douglas C. Rees Gary M. Fox 《Journal of Protein Chemistry》1995,14(5):263-274
High-affinity binding of basic fibroblast growth factor (bFGF) to the tyrosine kinase receptor requires cell-surface heparan sulfate proteoglycan or exogenous addition of heparin. The crystal structure of bFGF shows Arg40 and 45 on the surface opposite to the heparin-binding region, suggesting that these charged residues may be involved in the receptor binding. Therefore, these amino acids were mutated to aspartic acid separately or simultaneously, and also a simultaneous mutation to glutamic acid was introduced. These mutants displayed a mitogenic activity decreased greater than tenfold compared to the wild-type protein. Addition of heparin had no effect on the activity, while these mutants showed heparin-binding characteristics resembling those of the native sequence protein. The mutants exhibited decreased stability compared to the native sequence protein. Gradual changes in conformation were observed by circular dichroic and infrared spectroscopy. Heparin chromatography also showed the presence of denatured form for these mutants. However, in the presence of multivalent anions such as citrate, sucrose octasulfate, and heparin, the conformation of the mutants resembled that of the wild-type protein, as revealed by X-ray crystallography and circular dichroism spectra of the mutant with a Arg40 Asp substitution.Abbreviations FGF
fibroblast growth factor
- bFGF
basic FGF
- FBS
fetal bovine serum
- DMEM
Dulbecco's Modified Eagles Medium
- LMWH
low-molecular-weight heparin
- PBS
phosphate-buffered saline
- CD
circular dichroism
- FTIR
Fourier transform infrared spectroscopy
- MR
molecular replacement
- SIR
single isomorphous replacement
- EMTS
ethylmercurithiosalicylate
- SOS
sucrose octasulfate 相似文献
5.
Liselotte Larsson Gunnel Olsson Olle Hoist Hans T. Karlsson 《Biotechnology letters》1993,15(1):99-104
Experiments were done in order to study the thermophilic archaebacterium Acidianus brierleyi during oxidation of pyrite (FeS2). The microorganisms were grown both separated from the pyrite by a membrane and in close contact with the pyrite. From the results it can be concluded that direct contact is needed for good growth of the strain studied. The obtained results indicate that the direct contact mechanism may be applied to oxidation of sulfidic minerals by A. brierleyi. 相似文献
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P. Valentin-Hansen B. Hoist L. Søgaard-Andersen J. Martinussen J. Nesvera S. R. Douthwaite 《Molecular microbiology》1991,5(2):433-437
We have studied the deoP2 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-independent promoter and a sequence resembling the consensus -10 hexamer to strongly cAMP-CRP-activated promoters. 相似文献
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