References of "Moutzourelis, Georgios"
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See detailCrp of Streptomyces Coelicolor Is the Third Transcription Factor of the Large Crp-Fnr Superfamily Able to Bind Camp
Derouaux, Adeline ULg; Dehareng, Dominique ULg; Lecocq, Elke et al

in Biochemical and Biophysical Research Communications (2004), 325(3), 983-90

The chromosomal inactivation of the unique transcription factor of Streptomyces coelicolor that displays a cyclic-nucleotide-binding domain, Crp(Sco), led to a germination-defective phenotype similar to ... [more ▼]

The chromosomal inactivation of the unique transcription factor of Streptomyces coelicolor that displays a cyclic-nucleotide-binding domain, Crp(Sco), led to a germination-defective phenotype similar to the mutant of the adenylate cyclase gene (cya) unable to produce cAMP. By means of cAMP affinity chromatography we demonstrate the specific cAMP-binding ability of Crp(Sco), which definitely demonstrate that a Cya/cAMP/Crp system is used to trigger germination in S. coelicolor. However, electromobility shift assays with the purified Crp(Sco)-cAMP complex and the CRP-like cis-acting element of its own promoter failed. Moreover, we were unable to complement an Escherichia coli crp mutant in trans with Crp(Sco). The fact that Vfr from Pseudomonas aeruginosa and GlxR from Corynebacterium glutamicum could complement such an E. coli mutant suggests that the way Crp(Sco) interacts with DNA should mechanistically differ from its most similar members. This hypothesis was further supported by homology modelling of Crp(Sco) that confirmed an unusual organisation of the DNA-binding domain compared to the situation observed in Crp(Eco). [less ▲]

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See detailDeletion of a cyclic AMP receptor protein homologue diminishes germination and affects morphological development of Streptomyces coelicolor
Derouaux, Adeline ULg; Halici, S.; Nothaft, H. et al

in Journal of Bacteriology (2004), 186(6), 1893-1897

Open reading frame SCO3571 of Streptomyces coelicolor encodes a protein of the cyclic AMP (cAMP) receptor protein (CRP) superfamily of regulatory proteins. A mutant revealed a dramatic defect in ... [more ▼]

Open reading frame SCO3571 of Streptomyces coelicolor encodes a protein of the cyclic AMP (cAMP) receptor protein (CRP) superfamily of regulatory proteins. A mutant revealed a dramatic defect in germination, followed by growth delay and earlier sporulation. This phenotype correlates with those of an adenylate cyclase (cya) mutant that cannot synthesize cAMP. This finding suggests that S. coelicolor may use a Cya-cAMP-CRP system to trigger complex physiological processes such as morphogenesis. [less ▲]

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See detailThe fate of the Blal repressor during the induction of the Bacillus licheniformis BlaP beta-lactamase
Filée, Patrice ULg; Benlafya, Kamal; Delmarcelle, Michaël ULg et al

in Molecular Microbiology (2002), 44(3), 685-694

The induction of the Staphylococcus aureus BlaZ and Bacillus licheniformis 749/l BIaP beta-lactamases by beta-lactam antibiotics occurs according to similar processes. In both bacteria, the products of ... [more ▼]

The induction of the Staphylococcus aureus BlaZ and Bacillus licheniformis 749/l BIaP beta-lactamases by beta-lactam antibiotics occurs according to similar processes. In both bacteria, the products of the blal and blaR1 genes share a high degree of sequence homology and act as repressors and penicillin-sensory transducers respectively. It has been shown in S. aureus that the Blal repressor, which controls the expression of BlaZ negatively, is degraded after the addition of the inducer. In the present study, we followed the fate of Blal during beta-lactamase induction in B. licheniformis 749/l and in a recombinant Bacillus subtilis 168 strain harbouring the pDML995 plasmid, which carries the B. licheniformis blaP, blal and blaR1 genes. In contrast to the situation in B. licheniformis 749/l, beta-lactamase induction in B. subtilis 168/pDML995 was not correlated with the proteolysis of Blal. To exclude molecular variations undetectable by SDS-PAGE, two-dimensional gel electrophoresis was performed with cellular extracts from uninduced or induced B. subtilis 168/pDML995 cells. No variation in the Blal isoelectric point was observed in induced cells, whereas the DNA-binding property was lost. Cross-linking experiments with dithiobis(succimidylpropionate) confirmed that, in uninduced recombinant B. subtilis cells, Blat was present as a homodimer and that this situation was not altered in induced conditions. This latter result is incompatible with a mechanism of inactivation of Blal by proteolysis and suggests that the inactivation of Blal results from a non-covalent modification by a co-activator and that the subsequent proteolysis of Blal might be a secondary phenomenon. In addition to the presence of this co-activator, our results show that the presence of penicillin stress is also required for full induction of beta-lactamase biosynthesis. [less ▲]

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