The Mass Spectrometry society of Japan - The 68th Annual Conference on Mass Spectrometry, Japan
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Day 3, May 13（Wed.）　　Poster (1008/09)

3P-35　　PDF

Conformational Diversity of Vasotocin Nonapeptide Diastereomers Revealed by Uniform Field and Cyclic Traveling Wave Ion Mobility-Mass Spectrometry Measurements

(1Vanderbilt University, 2Waters, 3Nihon Waters)
Shawn Phillips1, Emanuel Zlibut1, Jody May1, John Mclean1, Martin Palmer2, Dale Cooper-shepherd2, James Langridge2, oMotoji Oshikata3

Vasotocin nonapeptides are 9-amino acid peptide hormones responsible for fluid regulation (vasopressin family) and promoting social bonding (oxytocin family) and are implicated in a variety of developmental disorders, including autism, depression, and schizophrenia. The mechanism of action involves binding to vascular receptors, and a synthetic analogue, desmopressin, has demonstrated significantly decreased binding affinity through the substitution of the 8th residue, L-arginine, with its enantiomer, D-arginine, suggesting this residue significantly impacts the resulting peptide conformation. Prior ion mobility-mass spectrometry (IM-MS) studies showed direct IM separation of chiral nonapeptides. Here we present results from IM-MS and cyclic traveling wave IM (cIM) that resolve additional conformer populations within these diastereomeric peptides, as well as evidence for interconverting conformers co-existing during IM-MS analyses.

Keywords:
Ion mobility, Diastereomer, peptide hormone, collisional cross section, CCS, HRMS

Novel Aspect:
Multiple conformer populations for lasso peptides revealed by high resolution cyclic IM and tandem IM/IM experiments.