def get_tail_coords(site):
    """
    For a given active site, go through the residues
    and return a list of coordinates for the last atoms
    of each residue. The last atom is simply the last
    element in the list of atoms for each residue in the
    active site

    Input: ActiveSite
    Output: List of Coordinates
    """

    # Grab the residues and upack the coordinates
    residues = site.residues
    coords = []

    for residue in residues:
        # Tail atoms are defined as the 
        # last element in the list of atoms 
        # for the given residue
        tail_atom = residue.atoms[-1]
        coords.append(tail_atom.coords) 

    return coords