• Journal of Microbiology and Biotechnology
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• 제10권5호
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• pp.670-676
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• 2000

Several clones obtained from Serratia marcescens stimulated E. coli TP2139 (${\Delta}lac, \;{\Delta} crp$) cells to use maltose as a carbon source. The crp gene clone, pCKB12, was confirmed to stimulate the $\beta$-galactosidase activity, by Southern hybridization [31]. The nucleotide sequence of the crp region consisting of 1,979 bp was determined. The sequencing of the fragment led to the identification of two open reading frames: One of these, the crp gene, encoded 210 amino acid and the other encoded a truncated protein. The S. marcescens and E. coli crp genes showed a higher degree of divergence in their nucleotide sequence with 120 changes, however, the corresponding amino acid sequences showed only two amino acid differences. Yet, an analysis of the amino acid divergence revealed that the catabolite gene activator protein, the crp gene product, was the most conserved protein observed so far. Using a crp-lac protein fusion, it was demonstrated that S. marcescens CRP could repress its own expression, probably via a mechanism similar to that previously described for the E. coli crp gene.

• 한국미생물·생명공학회지
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• 제21권3호
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• pp.229-238
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• 1993

An nlp (Ner like protein) gene from E. coli was previously cloned and sequenced. Here we show that expression of the sugar metabolism related genes, lacZ, malQ and malP, increased 2.5-to 8.3-fold in the presence of a plasmid containing the nlp gene. This suggested that the nlp gene could induce maltose- and lactose-metabolism coordinately with crp*1 in the absence of cAMP. Using the nlp-lacZ fusion gene, it was possible to show the promoter of nlp was active in vivo.

• Applied Biological Chemistry
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• 제39권3호
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• pp.195-199
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• 1996

$crp^{\ast}$ 유전자가 도입된 대장균 MK2001($crp^{{\ast}1}$}, cya::km)을 숙주로 사용하여 mal 유전자 발현을 촉진시키는 유전자의 하나인 sfs1(sugar fermentation stimulation)의 구조해석 결과에 의하면, 잠정적인 sfs1의 promoter 영역에는 CRP 단백질과의 결합영역으로 보이는 염기배열이 존재하였다. 본 실험에서는 sfs1 유전자의 cAMP-CRP에 의한 발현 조절을 확인하고자, lacZ 와의 융합 유전자를 작성하였다. 작성된 융합 유전자는 cya 결손주인 Tp2010에서 cAMP의 첨가에 의해 ${\beta}-galactosidase$ 활성이 크게 증가하였으며, Western blotting의 실험에서도 같은 결과를 나타냈다. in vivo에서 발현이 확인된 전사산물은 cAMP에 의해 전사 촉진이 일어났으며, CRP의 결합부위로 예상되는 DNA 영역은 cAMP가 존재하면 CRP 단백질과 결합하는 특성을 나타내었다. 이상의 결과로 보아, sfs1 유전자의 발현은 UMP-CRP에 의한 전사촉진 현상을 받는 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제19권12호
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• pp.1527-1535
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• 2009

Polyphosphate (polyP) plays diverse physiological functions in prokaryotes and eukaryotes, but most of their detailed mechanisms are still obscure. Here, we show that deletion of polyphosphate kinase (PPK), the principal enzyme responsible for synthesis of polyP, resulted in augmented expression of cAMP receptor protein (CRP) and rpoS and lowered $H_2O_2$ sensitivity in Salmonella Typhimurium ATCC14028. The binding of cAMP-CRP complex to rpoS promoter and further stimulation of its transcription were proved through electrophoretic mobility shift assay, lacZ fusion, and exogenous cAMP addition, respectively. The rpoS expression increased in cpdA (cAMP phosphodiesterase coding gene) mutant, further suggesting that cAMP-CRP upregulated rpoS expression. These results demonstrate that PPK affects oxidative stress response by modulating crp and rpoS expression in S. Typhimurium.