structure.GetAtomCount[]
- Function
- integer structure.GetAtomCount(integer segmentIndex)
- Description
- Returns the number of atoms in the specified segment.
- V1 Function Name
- none
structure.GetAtomCount returns the number of atoms in the specified segment of the protein. A segment can represent an amino acid, a ligand, RNA, or DNA.
The atom number can be used to create a band with band.AddBetweenSegments or band.Add.
Atom numbers are assigned to the heavy atoms (non-hydrogen atoms) first, starting with backbone, and then the sidechain. The hydrogens are numbered after the heavy atoms.
Many Foldit recipes band to the beta carbon of a sidechain to allow for freer movement. The beta carbon is the first nub or elbow in the sidechain. (Glycine does not have a sidechain, so a hydrogen takes the place of the beta carbon.) Except for the last segment, the beta carbon will always be atom number 5. The last segment has an extra oxygen atom in the backbone, which means the beta carbon is atom 6. (This logic only works for amino acid segments, and is not applicable to ligands, RNA, or DNA.)
A given amino acid always has the same number of atoms, except for the first and last segments of the protein. The first segment has two additional hydrogens, and the last segment has an additional oxygen. These extra atoms are returned in the value returned by structure.GetAtomCount().
See atom numbering for a complete discussion of atom numbering in Foldit.