scholarly journals Stable Structure for the Complex of Catabolite Activator Protein and Cyclic AMP: Molecular Mechanics Optimization by AMBER

2004 ◽  
Vol 5 ◽  
pp. 19-25
Author(s):  
Ryo Usuki ◽  
Yasuo Sengoku ◽  
Makoto Matsuoka ◽  
Shigenori Tanaka ◽  
Noriyuki Kurita
Keyword(s):  
Cyclic Amp ◽  
Molecular Mechanics ◽  
Stable Structure ◽  
Catabolite Activator Protein ◽  
Activator Protein

scholarly journals Multiple Control of Flagellum Biosynthesis in Escherichia coli: Role of H-NS Protein and the Cyclic AMP-Catabolite Activator Protein Complex in Transcription of the flhDC Master Operon

1999 ◽  
Vol 181 (24) ◽  
pp. 7500-7508 ◽  
Author(s):  
O. Soutourina ◽  
A. Kolb ◽  
E. Krin ◽  
C. Laurent-Winter ◽  
S. Rimsky ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Transcriptional Start Site ◽  
Regulatory Region ◽  
Start Codon ◽  
Transcriptional Fusion ◽  
Multiple Control ◽  
Catabolite Activator Protein ◽  
Activator Protein ◽  
Flagellum Biosynthesis

ABSTRACT Little is known about the molecular mechanism by which histone-like nucleoid-structuring (H-NS) protein and cyclic AMP-catabolite activator protein (CAP) complex control bacterial motility. In the present paper, we show that crp and hns mutants are nonmotile due to a complete lack of flagellin accumulation. This results from a reduced expression in vivo of fliA and fliC, which encode the specific flagellar sigma factor and flagellin, respectively. Overexpression of the flhDC master operon restored, at least in part, motility in crp andhns mutant strains, suggesting that this operon is the main target for both regulators. Binding of H-NS and CAP to the regulatory region of the master operon was demonstrated by gel retardation experiments, and their DNA binding sites were identified by DNase I footprinting assays. In vitro transcription experiments showed that CAP activates flhDC expression while H-NS represses it. In agreement with this observation, the activity of a transcriptional fusion carrying the flhDC promoter was decreased in thecrp strain and increased in the hns mutant. In contrast, the activity of a transcriptional fusion encompassing the entire flhDC regulatory region extending to the ATG translational start codon was strongly reduced in both hnsand crp mutants. These results suggest that the region downstream of the +1 transcriptional start site plays a crucial role in the positive control by H-NS of flagellum biosynthesis in vivo. Finally, the lack of complementation of the nonmotile phenotype in acrp mutant by activation-deficient CAP mutated proteins and characterization of cfs, a mutation resulting in a CAP-independent motility behavior, demonstrate that CAP activatesflhDC transcription by binding to its promoter and interacting with RNA polymerase.

scholarly journals Phototaxis and Impaired Motility in Adenylyl Cyclase and Cyclase Receptor Protein Mutants of Synechocystis sp. Strain PCC 6803

2006 ◽  
Vol 188 (20) ◽  
pp. 7306-7310 ◽  
Author(s):  
Devaki Bhaya ◽  
Kenlee Nakasugi ◽  
Fariba Fazeli ◽  
Matthew S. Burriesci
Keyword(s):  
Cyclic Amp ◽  
Adenylyl Cyclase ◽  
Receptor Protein ◽  
Wild Type ◽  
Catabolite Activator Protein ◽  
Activator Protein ◽  
Protein Mutants ◽  
Synechocystis Sp ◽  
Pcc 6803

ABSTRACT We have carefully characterized and reexamined the motility and phototactic responses of Synechocystis sp. adenylyl cyclase (Cya1) and catabolite activator protein (SYCRP1) mutants to different light regimens, glucose, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, and cyclic AMP. We find that contrary to earlier reports, cya1 and sycrp1 mutants are motile and phototactic but are impaired in one particular phase of phototaxis in comparison with wild-type Synechocystis sp.

scholarly journals The Transcriptional Factors MurR and Catabolite Activator Protein Regulate N-Acetylmuramic Acid Catabolism in Escherichia coli

2008 ◽  
Vol 190 (20) ◽  
pp. 6598-6608 ◽  
Author(s):  
Tina Jaeger ◽  
Christoph Mayer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Sole Source ◽  
Lag Phase ◽  
Face To Face ◽  
E Coli ◽  
Catabolite Activator Protein ◽  
Activator Protein ◽  
High Level ◽  
First Time

ABSTRACT The MurNAc etherase MurQ of Escherichia coli is essential for the catabolism of the bacterial cell wall sugar N-acetylmuramic acid (MurNAc) obtained either from the environment or from the endogenous cell wall (i.e., recycling). High-level expression of murQ is required for growth on MurNAc as the sole source of carbon and energy, whereas constitutive low-level expression of murQ is sufficient for the recycling of peptidoglycan fragments continuously released from the cell wall during growth of the bacteria. Here we characterize for the first time the expression of murQ and its regulation by MurR, a member of the poorly characterized RpiR/AlsR family of transcriptional regulators. Deleting murR abolished the extensive lag phase observed for E. coli grown on MurNAc and enhanced murQ transcription some 20-fold. MurR forms a stable multimer (most likely a tetramer) and binds to two adjacent inverted repeats within an operator region. In this way MurR represses transcription from the murQ promoter and also interferes with its own transcription. MurNAc-6-phosphate, the substrate of MurQ, was identified as a specific inducer that weakens binding of MurR to the operator. Moreover, murQ transcription depends on the activation by cyclic AMP (cAMP)-catabolite activator protein (CAP) bound to a class I site upstream of the murQ promoter. murR and murQ are divergently orientated and expressed from nonoverlapping face-to-face (convergent) promoters, yielding transcripts that are complementary at their 5′ ends. As a consequence of this unusual promoter arrangement, cAMP-CAP also affects murR transcription, presumably by acting as a roadblock for RNA polymerase.

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