title: Structure of the apo form of the catabolite control protein A (CcpA) from Bacillus megaterium with a DNA-binding domain.
abstract: Crystal structure determination of catabolite control protein A (CcpA) at 2.6 A resolution reveals for the first time the structure of a full-length apo-form LacI-GalR family repressor protein. In the crystal structures of these transcription regulators, the three-helix bundle of the DNA-binding domain has only been observed in cognate DNA complexes; it has not been observed in other crystal structures owing to its mobility. In the crystal packing of apo-CcpA, the protein-protein contacts between the N-terminal three-helix bundle and the core domain consisted of interactions between the homodimers that were similar to those between the corepressor protein HPr and the CcpA N-subdomain in the ternary DNA complex. In contrast to the DNA complex, the apo-CcpA structure reveals large subdomain movements in the core, resulting in a complete loss of contacts between the N-subdomains of the homodimer.
authors.affiliation: Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Strasse 4, D-17489 Greifswald, Germany.
authors.forename: Rajesh Kumar
authors.initials: RK
authors.lastname: Singh
authors.forename: Gottfried J
authors.initials: GJ
authors.lastname: Palm
authors.forename: Santosh
authors.initials: S
authors.lastname: Panjikar
authors.forename: Winfried
authors.initials: W
authors.lastname: Hinrichs
mesh_terms: D000494:Allosteric Regulation; D000595:Amino Acid Sequence; D001410:Bacillus megaterium / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D004269:DNA, Bacterial / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011487:Protein Conformation; D012097:Repressor Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D012097:Repressor Proteins; C069286:catabolite control proteins, bacteria