title: Left-handed DNA helices.
abstract: The synthetic DNA polymerpoly d(GC) . poly d(GC) has been studied by X-ray diffraction of orientated fibres in which it has either the well known (A or B) randed conformations have been observed with poly d(AC) . poly d(GT) and with poly d(As4T) . poly d(As4T), demonstrating that the novel structure is accessible to any DNA segment with an alternating purine-pyrimidine base sequence.
mesh_terms: D001483:Base Sequence; D003461:Crystallography; D004247:DNA; D009690:Nucleic Acid Conformation; D011687:Purines; D011743:Pyrimidines; D013329:Structure-Activity Relationship; D014961:X-Ray Diffraction
chemical_list: D011687:Purines; D011743:Pyrimidines; D004247:DNA