[The effect of specific mutation crp a in the genetic locus of receptor protein cAMP (CRP) on the expression of Escherichia coli K-12 deo-operon].
Expression of the deo operon of Escherichia coli is subjected to double negative control by DeoR and CytR repressors and to the positive control by cAMP-CRP complex. However, sensitivity of the deo operon to catabolite repression is only revealed in bacteria with disrupted synthesis of the CytR protein, since the function of the latter is to prevent CRP activation of the deo operon transcription. In the present work we have studied the influence of crpa specific mutation at the genetic locus of CRP protein on the expression of the deo operon of E. coli. It has been found that the presence of crpa mutation in bacterial genome completely eliminates CytR repression of the deo operon, so that activation of Deo enzymes synthesis by cAMP-CRPa complex becomes possible, even in the presence of CytR. Besides, the modified CRPa protein appears to block the activity of catabolite-sensitive deoPO2 promoter of the deo operon under conditions of cAMP deficiency, which is manifested in the two-fold decrease of deoR derepression in the crpa cells, as compared to the wild type bacteria during the growth on glucose containing medium. It has been supposed that both effects are due to increased affinity of the modified CRPa protein to the specific sites of catabolite sensitive promoters, as compared to the wild type CRP protein.
Nechaeva
G D
GD
Mironov
A S
AS
D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D009154:Mutation; D009876:Operon; D011401:Promoter Regions, Genetic; D011953:Receptors, Cyclic AMP / Q000235:genetics*; D015183:Restriction Mapping
D011953:Receptors, Cyclic AMP
Vliianie spetsificheskoĭ mutatsii crp a v geneticheskom lokuse belka-retseptora cAMP (CRP) na ékspessiiu deo-operona Escherichia coli K-12.