foreach my $ref (keys %$data){
	if($data->{$ref}->type eq 'ATOM'){
	    my $atom = $data->{$ref}->atom;
	    $self->{'atoms'}{$ref}=$atom;
	    $self->{'residues'}{$atom->chainId.$atom->resNumber}{$ref}=1;
	    $self->{'chain'}{$atom->chainId}{$atom->chainId.$atom->resNumber}{$ref}=1;
	}
    }