Microsolvation Effects on the Excited-State Dynamics of Protonated Tryptophan

Mercier, Sebastien; Boyarkin, Oleg V.; Kamariotis, Anthi; Guglielmi, Matteo; Tavernelli, Ivano; Cascella, M.; Röthlisberger, Ursula; Rizzo, Thomas R.

doi:10.1021/ja065980n

Cited by 147 publications

(161 citation statements)

References 45 publications

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“…The ions transmitted through the FAIMS device are introduced into the cold ion trap tandem mass spectrometer, which is described in detail elsewhere [27][28][29]. They are drawn into vacuum through a glass capillary with metalized ends and then pass a skimmer before they are collected in a hexapole ion trap.…”

Section: Methodsmentioning

confidence: 99%

Conformational Distribution of Bradykinin [bk + 2 H]²⁺ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

Παπαδόπουλος

Svendsen

Boyarkin

et al. 2012

J. Am. Soc. Mass Spectrom.

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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+2 H] 2+ ). Using FAIMS, we partially separate the electrosprayed [bk+2 H] 2+ ions into two conformational families and selectively introduce one of them at a time into a cold ion trap mass spectrometer, where we probe them by UV photofragment spectroscopy. Although the two conformational families have distinct electronic spectra, some cross-conformer contamination can be observed under certain conditions. We demonstrate that this contamination comes from isomerization of ions energized during and/or after their separation and not from incomplete separation of the initially electrosprayed conformations in the FAIMS stage. By varying the injection voltage of the ions into our mass spectrometer, we can intentionally induce isomerization to produce what seems to be a gas phase equilibrium distribution of conformers. This distribution is different from the one produced initially by electrospray, indicating that some of the conformers are kinetically trapped and may be related to conformers that are more favored in solution.

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Section: Methodsmentioning

confidence: 99%

Conformational Distribution of Bradykinin [bk + 2 H]²⁺ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

Παπαδόπουλος

Svendsen

Boyarkin

et al. 2012

J. Am. Soc. Mass Spectrom.

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“…The third kind of state lies higher in energy and can be characterized as a charge transfer state where the electron is localised on a π * CO orbital with respect to the amino acid plane. Note that within the TD-DFT framework, such charge transfer state is predicted to be the lowest singlet state, which turns to be an artefact of the DFT method 17,21 .…”

Section: Iii1 Protonated Tryptophanmentioning

confidence: 99%

UV photoinduced dynamics in protonated aromatic amino acid

et al. 2008

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UV photoinduced fragmentation of protonated aromatics amino acids have emerged the last few years, coming from a situation where nothing was known to what we think a good understanding of the optical properties. We will mainly focus this review on the tryptophan case. Three groups have mostly done spectroscopic studies and one has mainly been involved in dynamics studies of the excited states in the femtosecond/picosecond range and also in the fragmentation kinetics from nanosecond to millisecond. All these data, along with high level ab initio calculations, have shed light on the role of the different electronic states of the protonated molecules upon the fragmentation mechanisms.

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“…Highly resolved electronic spectra of cold molecules [46,47] allow labeling individual conformers via a UV transition followed by infrared depletion of the photofragment signal arising from the labeled conformer. Scanning an IR depletion laser generates selective vibrational spectra of only the labeled conformer [48][49][50][51].…”

Section: Introductionmentioning

confidence: 99%

Conformation-Specific Spectroscopy of Peptide Fragment Ions in a Low-Temperature Ion Trap

Wassermann

Boyarkin

Paizs

et al. 2012

J. Am. Soc. Mass Spectrom.

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We have applied conformer-selective infrared-ultraviolet (IR-UV) double-resonance photofragment spectroscopy at low temperatures in an ion trap mass spectrometer for the spectroscopic characterization of peptide fragment ions. We investigate b-and a-type ions formed by collisioninduced dissociation from protonated leucine-enkephalin. The vibrational analysis and assignment are supported by nitrogen-15 isotopic substitution of individual amino acid residues and assisted by density functional theory calculations. Under such conditions, b-type ions of different size are found to appear exclusively as linear oxazolone structures with protonation on the Nterminus, while a rearrangement reaction is confirmed for the a 4 ion in which the side chain of the C-terminal phenylalanine residue is transferred to the N-terminal side of the molecule. The vibrational spectra that we present here provide a particularly stringent test for theoretical approaches.

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Microsolvation Effects on the Excited-State Dynamics of Protonated Tryptophan

Cited by 147 publications

References 45 publications

Conformational Distribution of Bradykinin [bk + 2 H]²⁺ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

Conformational Distribution of Bradykinin [bk + 2 H]²⁺ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

UV photoinduced dynamics in protonated aromatic amino acid

Conformation-Specific Spectroscopy of Peptide Fragment Ions in a Low-Temperature Ion Trap

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Microsolvation Effects on the Excited-State Dynamics of Protonated Tryptophan

Cited by 147 publications

References 45 publications

Conformational Distribution of Bradykinin [bk + 2 H]2+ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

Conformational Distribution of Bradykinin [bk + 2 H]2+ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

UV photoinduced dynamics in protonated aromatic amino acid

Conformation-Specific Spectroscopy of Peptide Fragment Ions in a Low-Temperature Ion Trap

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Product

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Conformational Distribution of Bradykinin [bk + 2 H]²⁺ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

Conformational Distribution of Bradykinin [bk + 2 H]²⁺ Revealed by Cold Ion Spectroscopy Coupled with FAIMS