Indicates there is a problem in the chirality compared to that expected with an atom in the residue.
            Chiral centres for all compounds occurring in the PDB are described in the chemical component dictionary. 
            Chirality can be assessed in a number of ways, including calculation of the chiral volume, 
            e.g. for the Calpha of amino acids this is 2.6 or -2.6 Angstrom cubed for L or D configurations, respectively. 
            If the sign of the computed volume is incorrect, the handedness is wrong. 
            If the absolute volume is less than 0.7Å3 , the chiral centre has been modelled as a 
            planar moiety which is very likely to be erroneous. Chirality deviations are summarised per chain.