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Factors that influence helical preferences for singly charged gas-phase peptide ions: the effects of multiple potential charge-carrying sites
Journal article   Peer reviewed

Factors that influence helical preferences for singly charged gas-phase peptide ions: the effects of multiple potential charge-carrying sites

Janel R McLean, John A McLean, Zhaoxiang Wu, Christopher Becker, Lisa M Pérez, C Nick Pace, J Martin Scholtz and David H Russell
The journal of physical chemistry. B, Vol.114(2), pp.809-816
01/21/2010
DOI: 10.1021/jp9105103
PMCID: PMC2818683
PMID: 20000372

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Abstract

Ion mobility-mass spectrometry is used to investigate the structure(s) of a series of model peptide [M + H](+) ions to better understand how intrinsic properties affect structure in low dielectric environments. The influence of peptide length, amino acid sequence, and composition on gas-phase structure is examined for a series of model peptides that have been previously studied in solution. Collision cross sections for the [M + H](+) ions of Ac-(AAKAA)(n)Y-NH(2) (n = 3-6) and Ac-Y(AEAAKA)(n)F-NH(2) (n = 2-5) are reported and correlated with candidate structures generated using molecular modeling techniques. The [M + H](+) ions of the AAKAA peptide series each exhibit a single, dominant ion mobility arrival time distribution (ATD) which correlates to partial helical structures, whereas the [M + H](+) ions of the AEAAKA ion series are composed of ATDs which correlate to charge-solvated globules (i.e., the charge is coordinated or solvated by polar peptide functional groups). These data raise numerous questions concerning intrinsic properties (amino acid sequence and composition as well as charge location) that dictate gas-phase peptide ion structure, which may reflect trends for peptide ion structure in low dielectric environments, such as transmembrane segments.
Amino Acid Sequence Gases - chemistry Ions - chemistry Models, Molecular Peptides - chemistry Protein Structure, Secondary Spectrometry, Mass, Electrospray Ionization

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