title: Cocrystals of the DNA-binding domain of phage 434 repressor and a synthetic phage 434 operator.
abstract: The amino-terminal domain of the phage 434 repressor forms cocrystals with a synthetic phage 434 operator. The cocrystals diffract to at least 4 A, and x-ray crystallographic analysis of them is in progress. An analysis of the packing in the cocrystals shows that complexes consisting of dimers of amino-terminal domain bound specifically to operators are stacked end to end in longer protein-DNA rods parallel to the unit cell body diagonals. The DNA in the complexes has 10.5 base pairs per turn and a rise per base of 3.26 A--values consistent with B-form DNA--indicating that DNA is neither unwound nor overwound by bound repressor. The packing analysis suggests an approach that might facilitate the cocrystallization of other DNA-binding proteins with the DNA they recognize.
mesh_terms: D001482:Base Composition; D003090:Coliphages / Q000235:genetics*; D003460:Crystallization; D004926:Escherichia coli / Q000235:genetics*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000378:metabolism*; D009841:Oligonucleotides / Q000378:metabolism*; D009876:Operon; D011485:Protein Binding; D011487:Protein Conformation; D012097:Repressor Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D014961:X-Ray Diffraction
chemical_list: D009838:Oligodeoxyribonucleotides; D009841:Oligonucleotides; D012097:Repressor Proteins; D014157:Transcription Factors