Function atom14_to_atom37_for_residue 

pub fn atom14_to_atom37_for_residue(res3: &str) -> [Option<usize>; 14]

For a residue given by its 3-letter code, return the atom37 slot index for each of the 14 atom14 positions, or None if that slot is unoccupied.

The atom14 slot ordering matches the Residue::atoms14() method in featurize::utilities: [N, CA, C, O, CB, sidechain…].