Keywords: manual

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## alpha() -- make an -helix

`alpha(residues)`

> This makes restraints enforcing an -helix (mainchain conformation class ``A'') for the residue segment specified by residues (which can be created using the model.residue_range() function). The helix is restrained by binormal restraints, N-O hydrogen bonds, - distances for , -O distances for , and O-O distances for 6.1. Note that this requires all heavy atoms to be present to work properly, so will not work with the -only topology.

> To actually add the restraints, pass the new object to restraints.add(). See Section 2.2.10 for an example.