title: Crystallization and preliminary X-ray diffraction studies of the quorum-sensing regulator TraM from Agrobacterium tumefaciens.
abstract: 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 weight of 30 kDa in solution. Crystals have been obtained of both native and selenomethionine-substituted TraM by the vapour-diffusion method. Crystals diffract to 1.67 A and belong to the space group P2(1)2(1)2, with unit-cell parameters a = 76.43, b = 47.09, c = 47.46 A and two molecules in the asymmetric unit. A two-wavelength MAD data set for the selenomethionine-substituted form has been collected to a resolution of 2.0 A. The selenium substructure (five out of six possible sites) has been solved using direct methods.
authors.affiliation: Department of Biochemistry, IRBM P. Angeletti, 00040 Pomezia, Rome, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Vannini
authors.forename: Cinzia
authors.initials: C
authors.lastname: Volpari
authors.forename: Stefania
authors.initials: S
authors.lastname: Di Marco
mesh_terms: D016960:Agrobacterium tumefaciens / Q000737:chemistry* / Q000235:genetics; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D002850:Chromatography, Gel; D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D008027:Light; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016297:Mutagenesis, Site-Directed; D012542:Scattering, Radiation; D012645:Selenomethionine / Q000737:chemistry; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; C074281:TraM protein, bacterial; D012645:Selenomethionine