Chain identifier should be blank not A: ATOM   5565 CO    CO A 714      18.707  23.711  17.885  1.00 74.25      A   CO  
Unknown residue  CO: ATOM   5565 CO    CO   714      18.707  23.711  17.885  1.00 74.25      A   CO  
Chain identifier should be blank not B: ATOM   5590 CO    CO B 715      17.398  40.998  28.470  1.00 70.43      B   CO  
Unknown residue  CO: ATOM   5590 CO    CO   715      17.398  40.998  28.470  1.00 70.43      B   CO  

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