title: Protein-DNA conformational changes in the crystal structure of a lambda Cro-operator complex.
abstract: The structure of a complex of bacteriophage lambda Cro protein with a 17-base-pair operator has been determined at 3.9-A resolution. Isomorphous derivatives obtained by the synthesis of site-specific iodinated DNA oligomers were of critical importance in solving the structure. The crystal structure contains three independent Cro-operator complexes that have very similar, although not necessarily identical, conformations. In the complex, the protein dimer undergoes a large conformational change relative to the crystal structure of the free protein. One monomer rotates by about 40 degrees relative to the other, this being accomplished primarily by a twisting of the two beta-sheet strands that connect one monomer with the other. In the complex, the DNA is bent by about 40 degrees into the shape of a boomerang but maintains essentially Watson-Crick B-form. In contrast to other known protein-DNA complexes, the DNA is not stacked end-to-end. The structure confirms the general features of the model previously proposed for the interaction of Cro with DNA.
authors: Department of Physics, University of Oregon, Eugene 97403.
authors: R G
authors: RG
authors: Brennan
authors: S L
authors: SL
authors: Roderick
authors: Y
authors: Y
authors: Takeda
authors: B W
authors: BW
authors: Matthews
mesh_terms: D000595:Amino Acid Sequence; D010582:Bacteriophage lambda / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009876:Operon; D011485:Protein Binding; D011487:Protein Conformation; D012097:Repressor Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; D014961:X-Ray Diffraction
chemical_list: D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins