A possible family of B-like triple helix structures: Comparison with the Arnott A-like triple helix

Recent experimental studies of the structure of triple helices show that their conformation in solution differs from the A-like structure derived from diffraction data on triple helix fibers by Arnott and co-workers. Here we show by means of molecular modeling that a family of triple helix structures may exist with similar conformational energies, but with a variety of sugar puckers. The characteristics of these putative triple helices are analyzed for three different base sequences: (T.A×T) n , (C-G×C + ) n , and alternating (C.G×C + /T.A×T) n