title: Crystallization of a complex of cro repressor with a 17 base-pair operator.
abstract: Crystals of the lambda cro repressor complexed to a 17 base-pair synthetic binding site related to the OR3 operator have been obtained. The complex crystallizes in the hexagonal space group P6(2) (or P6(4)) with unit cell dimensions a = b = 154.8 A, c = 85.6 A. Preliminary photography reveals that the crystals are stable to X-rays and display measurable reflections to a resolution of about 3.7 A. The diffraction patterns suggest that the cro-DNA complexes are arranged in an open hexagonal network with the DNA fragments stacked end-to-end. The DNA is in the B-form but appears to be bent or curved into an approximate superhelix.
mesh_terms: D010582:Bacteriophage lambda / Q000235:genetics*; D003460:Crystallization; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D009875:Operator Regions, Genetic; D012097:Repressor Proteins; D014157:Transcription Factors; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; D014961:X-Ray Diffraction
chemical_list: D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D012097:Repressor Proteins; D014157:Transcription Factors; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins