01/2004 - Crystallization and preliminary X-ray diffraction studies of the quorum-sensing regulator TraM from Agrobacterium tumefaciens
TraM is a 11.4 kDa protein involved in the control of the conjugal transfer of Agrobacterium tumefaciens Ti plasmids by quorum-sensing. TraM was overexpressed and purified from Escherichia coli. This protein binds to the transcriptional regulator TraR, abolishing its function. Size-exclusion chromatography and dynamic light scattering show that the recombinant protein has an apparent molecular […]
11/2003 - The effects of heavy metal contamination on the soil arthropod community of a shooting range
Soils in clay pigeon shooting ranges can be seriously contaminated by heavy metals. The pellets contained in ammunition are composed of Pb, Sb, Ni, Zn, Mn and Cu. The total concentrations of these metals in soils, and the effects of their increasing levels on the arthropod community were investigated at seven sampling sites in a […]
10/2002 - Determination of the stoichiometry of noncovalent complexes using reverse-phase high-performance liquid chromatography coupled with electrospray ion trap mass spectrometry
An electrospray mass spectrometry-based methodology has been developed to have a fast and sensitive method for protein-cofactor stoichiometry determination. As model systems, we used two proteins which require the presence of cofactors for activity: TraR, a member of the LuxR family of quorum-sensing transcriptional regulators, which requires an acyl-homoserine lactone molecule called Agrobacterium autoinducer (AAI) […]
09/2002 - The crystal structure of the quorum sensing protein TraR bound to its autoinducer and target DNA
The quorum sensing system allows bacteria to sense their cell density and initiate an altered pattern of gene expression after a sufficient quorum of cells has accumulated. In Agrobacterium tumefaciens, quorum sensing controls conjugal transfer of the tumour- inducing plasmid, responsible for plant crown gall disease. The core components of this system are the transcriptional […]
08/2002 - Crystallization and preliminary X-ray diffraction studies of the transcriptional regulator TraR bound to its cofactor and to a specific DNA sequence
TraR is an Agrobacterium tumefaciens transcriptional regulator which binds the pheromone N-3-oxooctanoyl-L-homoserine lactone (AAI) in response to the bacterial population density. The TraR-AAI complex dimerizes and interacts with a specific 18-base-pair DNA sequence (TraBox), activating promoters containing this site. TraR was overexpressed and purified from Escherichia coli. Crystals of the ternary complex, in which dimeric […]
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