Sequence-Specific Fragmentation of Matrix-Assisted Laser-Desorbed Protein/Peptide Ions

Brown, Robert S.; Lennon, John J.

doi:10.1021/ac00117a027

Cited by 316 publications

(368 citation statements)

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“…Thus, different groups tried to sequence purified proteins spotted in sinapinic acid (SA) or 2,5-DHB. In 1995, MALDI-ISD was performed on different proteins such as bovine cytochrome c (12.2 kDa), bovine superoxide dismutase (15.6 kDa), and equine apomyoglobin (16.9 kDa) [41,42]. Numerous intense c-, z-, and y-fragments were observed between 850 m/z and 11,100 m/z.…”

Section: Maldi-isd and Top-down Strategiesmentioning

confidence: 99%

MALDI In-Source Decay, from Sequencing to Imaging

Debois

Smargiasso

Demeure

et al. 2012

Topics in Current Chemistry

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Matrix-assisted laser desorption/ionization (MALDI) is now a mature method allowing the identification and, more challenging, the quantification of biopolymers (proteins, nucleic acids, glycans, etc). MALDI spectra show mostly intact singly charged ions. To obtain fragments, the activation of singly charged precursors is necessary, but not efficient above 3.5 kDa, thus making MALDI MS/MS difficult for large species. In-source decay (ISD) is a prompt fragmentation reaction that can be induced thermally or by radicals. As fragments are formed in the source, precursor ions cannot be selected; however, the technique is not limited by the mass of the analyzed compounds and pseudo MS3 can be performed on intense fragments. The discovery of new matrices that enhance the ISD yield, combined with the high sensitivity of MALDI mass spectrometers, and software development, opens new perspectives. We first review the mechanisms involved in the ISD processes, then discuss ISD applications like top-down sequencing and post-translational modifications (PTMs) studies, and finally review MALDI-ISD tissue imaging applications.

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Section: Maldi-isd and Top-down Strategiesmentioning

confidence: 99%

MALDI In-Source Decay, from Sequencing to Imaging

Debois

Smargiasso

Demeure

et al. 2012

Topics in Current Chemistry

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“…Without ramping the laser fluence, one would not be able to distinguish whether these features resulted from chemicals present in the sample or fragmentation resulting from the process of ionization. This mechanism of fragment formation is traditionally termed in source decay (ISD) [42,43]. It should also be noted that ions that fragment after acceleration, but before the detector, have an energy defined by E frag ϭ E prec ϫ (m frag /m prec ) and would thus appear as unfocused metastable features in the spectrum.…”

Section: Mass Spectrometrymentioning

confidence: 99%

“…Thus, such studies ignore fragmentation post ionization. The experimental examination of the effect of laser fluence on ion fragmentation has also been investigated in dinucleotides [29], in protein complexes [41], and peptides [42,43]. This paper presents the results of our preliminary investigations of peptide fragmentation and sets the stage for a systematic investigation of peptide fragmentations in MALDI.…”

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confidence: 99%

Fragmentation of leucine enkephalin as a function of laser fluence in a MALDI TOF-TOF

Campbell¹,

Vestal²,

Blank

et al. 2007

J. Am. Soc. Mass Spectrom.

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The effects of laser fluence on ion formation in MALDI were studied using a tandem TOF mass spectrometer with a Nd-YAG laser and ␣-cyano hydrocinnamic acid matrix. Leucine enkephalin ionization and fragmentation were followed as a function of laser fluence ranging from the threshold of ion formation to the maximum available, that is, about 280 -930 mJ/mm 2 . The most notable finding was the appearance of immonium ions at fluence values close to threshold, increasing rapidly and then tapering in intensity with the appearance of typical backbone fragment ions. The data suggest the presence of two distinct environments for ion formation. One is associated with molecular desorption at low values of laser fluence that leads to extensive immonium ion formation. The second becomes dominant at higher fluences, is associated initially with backbone type fragments, but, at the highest values of fluence, progresses to immonium fragments. This second environment is suggestive of ion desorption from large pieces of material ablated from the surface. Arrhenius rate law considerations were used to estimate temperatures associated with the onset of these two processes. (J Am Soc Mass Spectrom 2007, 18, 607-616)

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“…M etastable decomposition occurs universally during matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analyses of molecules having labile bonds. Although this phenomenon can be used for obtaining analyte structural information for small peptides, oligosaccharides, and some glycolipids [1][2][3][4][5] for larger or more fragile molecules, it can limit the mass accuracy and resolution and complicate interpretation of the spectra of heterogeneous samples. Thus, it is important to develop methods that allow control of the extent of metastable decay.…”

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confidence: 99%

Ganglioside analysis by thin-layer chromatography matrix-assisted laser desorption/ionization orthogonal time-of-flight mass spectrometry

Ivleva

Sapp

O’Connor

et al. 2005

J. Am. Soc. Mass Spectrom.

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Metastable decomposition of ions generated in matrix-assisted laser desorption/ionization (MALDI) mass spectrometers complicates analysis of biological samples that have labile bonds. Recently, several academic laboratories and manufacturers of commercial instruments have designed instruments that introduce a cooling gas into the ion source during the MALDI event and have shown that the resulting vibrational cooling stabilizes these labile bonds. In this study, we compared stabilization and detection of desorbed gangliosides on a commercial orthogonal time-of-flight (oTOF) instrument with results we reported previously that had been obtained on a home-built Fourier transform mass spectrometer. Decoupling of the desorption/ ionization from the detection steps resulted in an opportunity for desorbing thin-layer chromatography (TLC)-separated gangliosides directly from a TLC plate without compromising mass spectral accuracy and resolution of the ganglioside analysis, thus coupling TLC and oTOF mass spectrometry. The application of a declustering potential allowed control of the matrix cluster and matrix adduct formation, and, thus, enhanced the detection of the gangliosides. during matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analyses of molecules having labile bonds. Although this phenomenon can be used for obtaining analyte structural information for small peptides, oligosaccharides, and some glycolipids [1-5] for larger or more fragile molecules, it can limit the mass accuracy and resolution and complicate interpretation of the spectra of heterogeneous samples. Thus, it is important to develop methods that allow control of the extent of metastable decay. In addition to the pressure of the background gas and extraction field strength in the MALDI technique, the major factors affecting metastable fragmentation are laser wavelength/pulse width and the choice of the MALDI matrix [6,7]. In addition, the presence of electrons may play a role in analyte fragmentation and may cause suppression of multiply charged ions in a spectrum [8,9].Control of the metastable fragmentation in MALDI by increasing the pressure in the ionization source and reduction of the ions internal energy was first introduced by Loboda et al. on orthogonal time-of-flight (oTOF) instruments [10] and later extended to Fourier transform mass spectrometry (FTMS) [11] and to the operation at atmospheric pressure on various types of instruments [12]. These methods have since been used for stabilization of glycolipids [13,14] and peptides and proteins [11,15]. The term vibrational cooling (VC) MALDI recently has been introduced to describe desorption in the pressure range where cooling of the excess bond energy is achieved [12]. Stabilization of the labile bonds under these conditions allows for control of the extent of fragmentation, which is particularly

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Sequence-Specific Fragmentation of Matrix-Assisted Laser-Desorbed Protein/Peptide Ions

Cited by 316 publications

References 0 publications

MALDI In-Source Decay, from Sequencing to Imaging

MALDI In-Source Decay, from Sequencing to Imaging

Fragmentation of leucine enkephalin as a function of laser fluence in a MALDI TOF-TOF

Ganglioside analysis by thin-layer chromatography matrix-assisted laser desorption/ionization orthogonal time-of-flight mass spectrometry

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