Chain identifier should be blank not A: ATOM   1509 ZN    ZN A 185       3.112   9.615  -9.217  1.00 15.49      A   ZN  
Chain identifier should be blank not B: ATOM   1547 ZN    ZN B 186     -17.667   8.393 -11.129  1.00 11.84      B   ZN  

1