IR SPECTROSCOPY ON PEPTIDES AND PROTEINS AFTER ION MOBILITY SELECTION AND IN LIQUID HELIUM DROPLETS

von Helden, Gert

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https://hdl.handle.net/2142/79266 Copy

Description

Title

IR SPECTROSCOPY ON PEPTIDES AND PROTEINS AFTER ION MOBILITY SELECTION AND IN LIQUID HELIUM DROPLETS

Author(s)

von Helden, Gert

Issue Date

24-Jun-15

Keyword(s)

Mini-symposium: Accelerator-Based Spectroscopy

Abstract

IR spectroscopy has become a frequently used tool to characterize gas-phase peptides and proteins. In many experiments, ions are m/z selected, irradiated by intense and tunable IR light and fragmentation is monitored as a function of IR wavelength. The presence of different conformers can, however, complicate the interpretation, as the resulting spectra represent the sum of the spectra of the individual components. We constructed a setup, in which ion mobility methods are used to obtain m/z selected ions of defined shape on which are then further investigated by IR spectroscopy. First results on peptide aggregates are presented and for some of those, the IR spectra show a transition from helical or random coil to beta sheet structures.\ In a different experiment, peptide or protein ions are captures in liquid helium droplets prior to IR spectroscopic investigation. The conditions inside a helium droplet are isothermal at 0.38 K and the interaction between the helium matrix and the molecules are weak so that only small perturbations on the molecule are expected. IR spectra for m/z selected peptides with up to 10 aminoacids and proteins containing more than 100 aminoacids have been measured. The spectra of the smaller species show resolved bands of individual oscillators, which can be used for structure assignment. For the larger species, band envelopes are obtained and for the case of highly charged proteins, a transition form helical to extended structures is observed.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

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http://hdl.handle.net/2142/79266

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