Mass Spectrometry Approaches for Determining the Structure of Antimicrobial Peptides.

In the past decades, a great amount of antimicrobial peptides (AMPs) has been discovered, the structure identification of which relies heavily on de novo sequencing by Edman degradation or mass spectrometry. Here we outline the basic procedures for the exact mass measurement approaches that use off-line low-energy CID ESI Qq-TOF MS/MS in positive-ion mode, which is typically applied to de novo sequencing of peptides, to elucidate the structure of AMPs. Ambiguity I/L and partial sequence order were elucidated by Edman degradation or/and structural similarity analysis to known sequence. The approaches can determine the structure of peptides composed of as much as 38 amino acids in our practice.