Hemolytic activity of MBP-ClosA T46A and structures of identified PTM peptides. A, synthetase reactions using MBP-ClosA T46A and SagB/ClosC/ClosD. Hemolytic activity was normalized against a Triton X-100 positive control. Lane 1, wt ClosA and SagB/ClosC/ClosD; lane 2, SagB/ClosC/ClosD only; lane 3, ClosA T46A and SagB/ClosC/ClosD. B, peptide 1, CLS peptide containing a methyloxazole at position Thr46; peptide 2, SLS peptide containing two oxazoles at positions Ser46 and Ser48.