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 […]
12/2001 - Effect of ibuprofen and warfarin on the allosteric properties of haem-human serum albumin. A spectroscopic study
Haem binding to human serum albumin (HSA) endows the protein with peculiar spectroscopic properties. Here, the effect of ibuprofen and warfarin on the spectroscopic properties of ferric haem-human serum albumin (ferric HSA-haem) and of ferrous nitrosylated haem-human serum albumin (ferrous HSA-haem-NO) is reported. Ferric HSA-haem is hexa-coordinated, the haem-iron atom being bonded to His105 and […]
06/2001 - Relaxometric characterization of human hemalbumin
Hemalbumin [i.e., Fe(III)-protoporphyrin IX-human serum albumin; Fe(III)heme-HSA] is an important intermediate in the recovery of heme iron following hemolysis. Relaxometric data are consistent with the occurrence of a hexacoordinated high-spin Fe(III) center with no water in the inner coordination sphere. The relatively high relaxation enhancement observed for an aqueous solution of Fe(III)heme-HSA (r1p=4.8 mM(-1)s(-1) at […]
04/2001 - Effect of bezafibrate and clofibrate on the heme-iron geometry of ferrous nitrosylated heme-human serum albumin: an EPR study
The effect of bezafibrate (BZF) and clofibrate (CF), two therapeutic drugs displaying anticoagulant and antihyperlipoproteinemic activities, on the EPR-spectroscopic properties of ferrous nitrosylated heme-human serum albumin (HSA-heme-NO) has been investigated. In the absence of BZF and CF, HSA-heme-NO is a five-coordinate heme-iron system, characterised by an X-band EPR spectrum with a three-line splitting in the […]
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