Structure and conformation of helical nucleic acids: rebuilding program (SCHNArP).

We present a program, SCHNArP, for rebuilding double-helical nucleic acid structures from a set of helical parameters. The parameter sets are based on mathematically reversible schemes that allow direct comparison of data from experimental X-ray crystal structures analyzed using the analysis program, SCHNAaP (see accompanying paper), and structures built using the rebuilding program, SCHNArP. The program uses either local CEHS helical parameters or global helical parameters. A number of standard parameter sets from the literature are included that allow comparison of oligomer and polymer structures generated using different models for sequence-dependent DNA bending. Exact atomic models are provided for the bases. Schematic models that trace the path of the backbone and use rectangular blocks for the bases can be generated. Copyright 1997 Academic Press Limited.