A uniform field ion mobility study of melittin and implications of low-field mobility for resolving fine cross-sectional detail in peptide and protein experiments.

摘要: An experimental investigation of protonated melittin was undertaken using uniform field ion mobility-mass spectrometry (IM-MS) to measure helium-based collision cross sections (CCS). Upon varying the electrospray solvent from aqueous methanol, [M + 2H](2+) species observed shift a compact an extended CCS, suggesting gas-phase structural transition which depends on initial conditions. The 3H](3+), 4H](4+), and 5H](5+) exhibited peak broadening in response organic solvent, but retained their these are locked into stable structure. CCS 3H](3+) 4H](4+) were found be similar, ions adopt structurally similar features gas phase, which, based previous studies, likely retains α-helical characteristics. We also report resolution additional low-abundance mobility sensitive magnitude drift field. observe loss peptide above ca. eight Townsends, that ability resolve subtle details is inherently related conducting measurements at low under conditions minimize heating.