Sheet() — make a β-sheet

Sheet(atom1, atom2, sheet_h_bonds)

This calculates H-bonding restraints for a pair of β-strands. atom1 and atom2 specify the first H-bond in the β-sheet ladder. sheet_h_bonds specifies the number of H-bonds to be added — positive for a parallel sheet, and negative for an anti-parallel sheet. In a parallel sheet, hydrogen bonds start at the first or the second term of the following series (depending on atom1 and atom2): 1N:1O, 1O:3N, 3N:3O, 3O:5N, etc. For an anti-parallel sheet, the corresponding series is 1N:3O, 1O:3N, 3N:1O, 3O:1N, etc. (note that the residue indices run in decreasing order for the second strand in this case). The extended structure of the individual strands themselves is not enforced; use separate Strand() restraints if so desired.

All of the restraints have the physical.h_bond physical restraint type, so can be strengthened or weakened by creating a physical.Values() object (see also Section 2.2.2).

To actually add the restraints, pass the new object to Restraints.add(). See Section 2.2.11 for an example.