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 TraR-AAI is bound to the TraBox sequence, have been obtained by the vapour-diffusion method. The crystals belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 66.99, b = 94.67, c = 209.66 A, with two (TraR-AAI)(2)-TraBox complexes in the asymmetric unit. A three-wavelength MAD data set for the seleno-L-methionine-substituted form has been collected to a resolution of 3 A. 20 of the 24 crystallographically independent selenium sites were located as part of the MAD-phasing process.
Vannini
Alessandro
A
Department of Biochemistry, IRBM P. Angeletti, 00040 Pomezia, Rome, Italy.
Volpari
Cinzia
C
Gargioli
Cesare
C
Muraglia
Ester
E
De Francesco
Raffaele
R
Neddermann
Petra
P
Di Marco
Stefania
S
D016960:Agrobacterium tumefaciens / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification; D001483:Base Sequence; D001665:Binding Sites; D003460:Crystallization; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry; D006714:Homoserine / Q000031:analogs & derivatives* / Q000737:chemistry; D046911:Macromolecular Substances; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification; D012643:Selenium
D001426:Bacterial Proteins; D046911:Macromolecular Substances; D011994:Recombinant Proteins; C080512:TraR protein, Agrobacterium tumefaciens; C080518:N-(beta-oxooctan-1-oyl)homoserine lactone; D006714:Homoserine; D004247:DNA; D012643:Selenium