making sure there are no invalid amino acids
making sure there are no invalid amino acids

UNC-Major-Lab/Fragment-Isotope-Distribution-Paper,UNC-Major-Lab/Fragment-Isotope-Distribution-Paper,UNC-Major-Lab/Fragment-Isotope-Distribution-Paper,UNC-Major-Lab/Fragment-Isotope-Distribution-Paper,UNC-Major-Lab/Fragment-Isotope-Distribution-Paper,UNC-Major-Lab/Fragment-Isotope-Distribution-Paper