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Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter waves and acoustic waves can also be considered forms of radiative energy, and recently gravitational waves have been associated with a spectral signature in the context of the Laser Interferometer Gravitational-Wave Observatory (LIGO).
Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides which have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. Peptides fall under the broad chemical classes of biological polymers and oligomers, alongside nucleic acids, oligosaccharides, polysaccharides, and others.
In chemistry, conformational isomerism is a form of stereoisomerism in which the isomers can be interconverted just by rotations about formally single bonds (refer to figure on single bond rotation). While any two arrangements of atoms in a molecule that differ by rotation about single bonds can be referred to as different conformations, conformations that correspond to local minima on the potential energy surface are specifically called conformational isomers or conformers.
We present in this work experiments that push the limits of cold ion spectroscopy to the study of complex peptides and small proteins in the gas phase. Although the low temperature attainable in a col
EPFL2012
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We describe here experiments that combine differential ion mobility, which separates conformational isomers of biomolecular ions, with electronic spectroscopy in a cold, radio-frequency ion trap. Alth
2011
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We employ Cold Ion Spectroscopy (CIS) in conjunction with high-Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) to study the peptide bradykinin in its doubly protonated charge state ([bk+2H