Syntax:  strands {<boolean>}
         strands <value>

The RasMol strands command displays the currently loaded protein or nucleic acid as a smooth "ribbon" of depth-cued curves passing along the backbone of the protein. The ribbon is composed of a number of strands that run parallel to one another along the peptide plane of each residue. The ribbon is drawn between each amino acid whose alpha carbon is currently selected. The colour of the ribbon is changed by the RasMol colour ribbon command. If the current ribbon colour is none (the default), the colour is taken from the alpha carbon at each position along its length. The colour of the central and outermost strands may be coloured independently using the colour ribbon1 and colour ribbon2 commands respectively. The number of strands in the ribbon may be altered using the RasMol set strands command.

The width of the ribbon at each position is determined by the optional parameter in the usual RasMol units. By default the width of the ribbon is taken from the secondary structure of the protein or a constant value of 720 for nucleic acids (which produces a ribbon 2.88 Angstroms wide). The default width of protein alpha helices and beta sheets is 380 (1.52 Angstroms) and 100 (0.4 Angstroms) for turns and random coil. The secondary structure assignment is either from the PDB file or calculated using the DSSP algorithm as used by the structure command. This command is similar to the RasMol command ribbons which renders the biomolecular ribbon as a smooth shaded surface.