title: Prediction of peptide ion mobilities via a priori calculations from intrinsic size parameters of amino acid residues.
abstract: Ion mobility spectrometry (IMS) has recently been established as a powerful tool to separate the protease digest mixtures and identify their peptide components. As accurate calculation of mobilities is critical for this technique, a new rapid method based on intrinsic size parameters (ISPs) of amino acid residues has been devised. However, those parameters had to be obtained by tedious statistical analysis of a large body of experimental data. Here we demonstrate that they can instead be derived a priori, based on the stoichiometry of a residue. Our main finding is that the ISP of a residue is essentially determined by its density, that is, the average mass/size ratio of its constituent atoms. This is in accordance with an interpretation in which peptides assume compact conformations in the gas phase dominated by the solvation of ionic charge.
authors.affiliation: Department of Chemistry and Centre for Research in Mass Spectrometry, York University, Toronto, Ontario, Canada.
authors.forename: A A
authors.initials: AA
authors.lastname: Shvartsburg
authors.forename: K W
authors.initials: KW
authors.lastname: Siu
authors.forename: D E
authors.initials: DE
authors.lastname: Clemmer
mesh_terms: D000465:Algorithms; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis*; D000818:Animals; D013058:Mass Spectrometry; D008962:Models, Theoretical; D009211:Myoglobin / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D010751:Phosphopyruvate Hydratase / Q000737:chemistry; D011487:Protein Conformation; D017421:Sequence Analysis / Q000295:instrumentation / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization; D014907:Whales; D015003:Yeasts
chemical_list: D000596:Amino Acids; D009211:Myoglobin; D010455:Peptides; D010751:Phosphopyruvate Hydratase