Photodissociation of singly protonated peptides at 193 nm investigated with tandem time‐of‐flight mass spectrometry

101

Several groups have investigated the photodissociation of peptide ions with ultraviolet light. Significant differences have been reported with 157 and 193 nm excitation. Recent studies have shown that the mass analyzer can also influence the observed photofragment distribution.Comparison of experiments using different peptides, wavelengths, and mass analyzers is undesirably complicated. In the present work, several peptides are analyzed with both 157 and 193 nm photodissociation in tandem-TOF and linear ion trap mass spectrometers. The results indicate that the fragment ion distribution can be influenced by both the photodissociation wavelength and the mass analyzer. The two wavelengths generate similar spectra in an ion trap but quite different results in a tandem

Section: Discussionmentioning

confidence: 99%

Factors that impact the vacuum ultraviolet photofragmentation of peptide ions

Thompson

Cui

Reilly

2007

101

“…Melittin, kassinin, Lys [0]bradykinin, bradykinin, dynorphin-␤, GSK-␤ ␤ inhibitor, myosin kinase inhibitor, and mouse ANP [1][2][3][4][5][6][7][8][9][10][11] were purchased from American Peptide Company (Sunnyvale, CA). Polyalanine peptides were synthesized in-house using standard Fmoc coupling methodology.…”

Section: Methodsmentioning

confidence: 99%

“…It is demonstrated that a naphthyl based 18-crown-6 adduct is ideally suited for attaching to a variety peptides and fragmenting them following absorption of 266 nm light. [7][8][9][10][11]. Though none of these techniques is perfect, each has characteristic strengths and weaknesses.…”

mentioning

confidence: 99%

“…here are a variety of mainstream fragmentation methodologies available for interrogating peptides, including collision-induced dissociation (CID) [1], infrared multiphoton photodissociation (IRMPD) [2], electron capture dissociation (ECD) [3], and electron-transfer dissociation (ETD) [4]. In addition, there are other methods that can be used, such as surface induced dissociation (SID) [5], black-body infrared radiative dissociation (BIRD) [6], along with various photodissociation experiments employing high-energy lasers [7][8][9][10][11]. Though none of these techniques is perfect, each has characteristic strengths and weaknesses.…”

mentioning

confidence: 99%

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Rapid peptide fragmentation without electrons, collisions, infrared radiation, or native chromophores

Yeh

Sun

Meneses

et al. 2009

Ultraviolet photodissociation of peptides followed by mass analysis has several desirable advantages relative to other methods, yet it has not found widespread use due to several limitations. One shortcoming is the inefficiency with which peptides absorb in the ultraviolet. This issue has a simple solution and can be circumvented by the attachment of noncovalent adducts that contain appropriate chromophores. Subsequent photoactivation of the chromophore leads to vibrational excitation of the complex and eventually to fragmentation of the peptide. Herein, the energetics that control the efficiency of this process are examined as a function of the characteristics of both the peptide and the noncovalently attached chromophore. Fragmentation efficiency decreases with increasing peptide size and is also constrained by the binding energy of the noncovalent adduct. The optimum chromophore should have excellent absorption at the excitation wavelength and a low luminescence quantum yield. It is demonstrated that a naphthyl based 18-crown-6 adduct is ideally suited for attaching to a variety peptides and fragmenting them following absorption of 266 nm light. [7][8][9][10][11]. Though none of these techniques is perfect, each has characteristic strengths and weaknesses. For example CID is easily employed in the source region of any instrument with atmospheric pressure ionization. CID is also easily accommodated elsewhere in an instrument as long as high vacuum is not required. In contrast, IRMPD is well suited for collisionless environments. In this regard, CID and IRMPD provide complementary capabilities. Furthermore, since both methods fragment ions by the stepwise addition of small amounts of energy, the results obtained are frequently quite similar.However, CID and IRMPD are both limited by the fact that energy deposition occurs over a relatively long time scale, typically milliseconds to seconds. In contrast, ultraviolet photodissociation (UVPD) occurs on a much shorter time scale and can yield fragment ions characteristic of CID or IRMPD. However, the major limitation of UVPD is that the precursor ion must contain a suitable chromophore. For peptides, UVPD requires either short wavelength lasers (less than 200 nm) or peptides rich in tyrosine, tryptophan, and phenylalanine that can absorb at longer wavelengths. Therefore, UVPD is either limited to a small subset of all peptides or constrained by undesirable technical challenges which are encountered when working in the vacuum ultraviolet. Thus, widespread implementation of UVPD for peptide fragmentation has been to date somewhat limited.However, Brodbelt and coworkers have recently described a method to circumvent the requirement for aromatic residues or short wavelength lasers [12]. In this work, a noncovalently attached chromophore was used to absorb energy from a photon and transfer it to a peptide, causing the peptide to fragment. 18-crown-6 ether (18C6), which preferentially associates with lysine residues via the formation of three hydrogen bonds, was used for...

“…The internal energy acquired by a precursor ion at the time of its formation can be the driving force for its dissociation such as in post-source decay (PSD) [6]. Dissociation can be further enhanced by using ion activation techniques such as collisionally activated dissociation (CAD) [3,7], ultraviolet photodissociation (UV-PD) [8,9], electron capture dissociation (ECD) [10], and electrontransfer dissociation (ETD) [11].…”

mentioning

confidence: 99%

Observation of phosphorylation site-specific dissociation of singly protonated phosphopeptides

Shin

Moon

Kim

2010

Self Cite

In ultraviolet photodissociation of phosphopeptide ions with a basic residue (arginine, lysine, or histidine) at the N-terminus, intense a n Ϫ 97 peaks were observed. These ions were formed by cleavage at phosphorylated residues only. For multiply phosphorylated peptides, this site-specific cleavage occurred at every phosphorylated residue. H/D exchange studies showed that a n Ϫ 97 was formed by H 3 PO 4 loss from a n ϩ 1 radical cations. The site-specificity of phosphate loss observed here is in contrast to the nonspecific phosphate loss from b n and y n reported previously. Characteristics of the reaction and its potential utility for phosphopeptide analysis are discussed. (J Am Soc Mass Spectrom 2010, 21, 53-59)