Chain identifier should be blank not A: ATOM   2869 MG    MG A 357       1.949  25.258  35.482  1.00 10.93      A   MG  
Chain identifier should be blank not B: ATOM   2910 MG    MG B 358       5.581  50.538  53.627  1.00 12.83      B   MG  

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