title: Crystallization and preliminary X-ray analyses of catabolite control protein A, free and in complex with its DNA-binding site.
abstract: The catabolite control protein (CcpA) from Bacillus megaterium is a member of the bacterial repressor protein family GalR/LacI. CcpA with an N-terminal His-tag was used for crystallization. Crystals of free CcpA and of CcpA in complex with the putative operator sequence (catabolite responsive elements, CRE) were obtained by vapour-diffusion techniques at 291 K using the hanging-drop method. CcpA crystals grown in the presence of polyethylene glycol 8000 belong to the hexagonal space group P6(1)22 or P6(5)22, with unit-cell parameters a = 74.4, c = 238.8 A. These crystals diffract X-rays to 2.55 A resolution and contain one monomer of the homodimeric protein per asymmetric unit. Crystals of the CcpA-CRE complex were obtained with ammonium sulfate as precipitant and belong to the tetragonal space group I4(1)22, with unit-cell parameters a = 125, c = 400 A and one complex per asymmetric unit. Although these co-crystals grew to a sufficient size, X-ray diffraction was limited to 8 A resolution.
authors.affiliation: Institut für Kristallographie, Freie Universität Berlin, Takustrasse 6, D-14195 Berlin, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Tebbe
authors.forename: P
authors.initials: P
authors.lastname: Orth
authors.forename: E K
authors.initials: EK
authors.lastname: Küster-Schöck
authors.forename: W
authors.initials: W
authors.lastname: Hillen
authors.forename: W
authors.initials: W
authors.lastname: Saenger
authors.forename: W
authors.initials: W
authors.lastname: Hinrichs
mesh_terms: D000595:Amino Acid Sequence; D001410:Bacillus megaterium / Q000737:chemistry / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*; D001483:Base Sequence; D001665:Binding Sites; D003460:Crystallization; D018360:Crystallography, X-Ray; D004269:DNA, Bacterial / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*; D004926:Escherichia coli / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D012097:Repressor Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D011994:Recombinant Proteins; D012097:Repressor Proteins; C069286:catabolite control proteins, bacteria