Berlin 2005 – scientific programme

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MS: Massenspektrometrie

MS 1: Ionenfallen

MS 1.4: Talk

Friday, March 4, 2005, 11:15–11:30, HU 3088

Infrared spectroscopy of gas-phase proteins — •Gert von Helden¹, Jos Oomens², Nick Polfer², David T. Moore², Lex van der Meer², Alan G. Marshall³, John R. Eyler⁴, and Gerard Meijer¹ — ¹Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin — ²FOM Institute for Plasma Physics, Edisonbaan 14, NL-3439 MN Nieuwegein — ³National High Magnetic Field Laboratory, 1800 E. Paul Dirac Drive, Tallahassee, FL 32310-4005, USA — ⁴Department of Chemistry, University of Florida , Gainesville, FL 32611-7200, USA

The combination of an FT-ICR mass spectrometer with an infrared (IR) free electron laser is used to record IR spectra of a 104 amino-acid protein in the gas phase as a function of its charge state. The spectra are observed to contain clearly resolvable bands in the amide I and II spectral region. Compared to solution, the amide I band is blue-shifted and the amide II band red-shifted, as expected for species in an environment with reduced hydrogen bonding. The band positions are suggestive of a mostly α-helical structure of the protein and their widths are comparable to those in solution, indicating a similar conformational distribution.