Identification and Structural Characterisation of Carboxy-Terminal Polypeptides and Antibody Epitopes of Alzheimer's Amyloid Precursor Protein Using High-Resolution Mass Spectrometry

2005 ◽  
Vol 11 (5) ◽  
pp. 547-555 ◽  
Author(s):  
Xiaodan Tian ◽  
Roxana Cecal ◽  
JoAnne McLaurin ◽  
Marilena Manea ◽  
Raluca Stefanescu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Amyloid Precursor Protein ◽  
Vaccine Development ◽  
Precursor Protein ◽  
Therapeutic Effects ◽  
Amyloid A ◽  
Carboxy Terminal ◽  
Ft Icr Ms ◽  
Ft Icr

Alzheimer's disease (AD) is the most common cause for human age-related dementia, characterised by formation of diffuse plaques in the brain that are directly involved in AD pathogenesis. The major component of AD plaques is ß-amyloid, a 40 to 42 amino acid polypeptide derived from the amyloid precursor protein (APP) by proteolytic degradation involving the specific proteases, ß-and γ-secretase acting at the N- and C-terminal cleavage site, respectively. In this study, we have prepared polypeptides comprising the carboxy-terminal and transmembrane sequences of APP, by bacterial expression and chemical synthesis, as substrates for studying the C-terminal processing of APP and its interaction with the γ-secretase complex. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) was used as a major tool for structure analysis. Immunisation of transgenic mouse models of AD with Aß42 has been recently shown to be effective to inhibit and disaggregate Aß-fibrils, and to reduce AD-related neuropathology and memory impairments. However, the mechanism underlying these therapeutic effects as yet has been unclear. Using proteolytic epitope excision from immune complexes in combination with FT-ICR-MS, we identified the epitope recognised by the therapeutically active antibody as the N-terminal Aß(4–10) sequence; this soluble, nontoxic epitope opens new lead structures for AD vaccine development. A monoclonal antibody (Jonas; JmAb) directed against the cytosolic APP domain was used in studies of APP biochemistry and metabolism. Here, we report the identification of the epitope recognised by the JmAb, using the combination of epitope excision and peptide mapping by FT-ICR-MS. The epitope was determined to be located at the C-terminal APP(740–747) sequence; it was confirmed by ELISA binding assays and authentic synthetic peptides and will be an efficient tool in the development of new specific vaccines. These results demonstrate high-resolution FT-ICR-MS as a powerful method for characterising biochemical pathways and molecular recognition structures of APP.

Revealing the complex composition of lignin and resulting products by ultra-high resolution mass spectrometry (FT-ICR MS)

2018 ◽  
Vol 44 ◽  
pp. S47
Author(s):  
L. Horsfall ◽  
V. Echavarri-Bravo ◽  
M. Tinzl ◽  
W. Kew ◽  
L. Mackay ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
High Resolution Mass Spectrometry ◽  
Complex Composition ◽  
High Resolution Mass ◽  
Ft Icr Ms ◽  
Ft Icr ◽  
Resolution Mass

Using polar nitrogen-, sulphur- and oxygen-compound compositions from ultra-high resolution mass spectrometry for petroleum fluid assessment in the Eagle Ford Formation, Texas

2019 ◽  
Vol 484 (1) ◽  
pp. 71-96 ◽  
Author(s):  
S. Poetz ◽  
S. Kuske ◽  
Y. Song ◽  
J. Jweda ◽  
E. Michael ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Depositional Environment ◽  
High Resolution Mass Spectrometry ◽  
Petroleum System ◽  
Oxygen Compound ◽  
Eagle Ford ◽  
Ft Icr Ms ◽  
Ft Icr ◽  
Resolution Mass

AbstractThe potential of polar compound compositions from electrospray ionization ultra-high resolution mass spectrometry (FT-ICR-MS) to characterize petroleum fluids as well as petroleum system processes is shown in the example of the Eagle Ford Formation in Texas, USA. A set of six black oil and nine source-rock bitumen samples is investigated with respect to its organic nitrogen-, sulphur- and oxygen-compound inventory in order to assess maturity, depositional environment, lithofacies and retention and migration behaviour. Compared to conventional geochemical tools based on molecular parameters from gas chromatographic analyses, FT-ICR-MS enables a maturity assessment from immature to late mature stage, which is barely influenced by source or depositional environment. Due to the increased molecular mass and polarity range of its target compounds, FT-ICR-MS is the most convincing tool to describe the retention and fractionation of polar compounds in a petroleum system.

scholarly journals High resolution fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) for the characterisation of enzymatic processing of commercial lignin

2019 ◽  
Vol 52 ◽  
pp. 1-8 ◽  
Author(s):  
Virginia Echavarri-Bravo ◽  
Matthias Tinzl ◽  
Will Kew ◽  
Faye Cruickshank ◽  
C. Logan Mackay ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Fourier Transform ◽  
High Resolution ◽  
Cyclotron Resonance ◽  
Ion Cyclotron Resonance ◽  
Ion Cyclotron ◽  
Ft Icr Ms ◽  
Ft Icr

scholarly journals Discovery of Cisplatin Binding to Thymine and Cytosine on a Single-Stranded Oligodeoxynucleotide by High Resolution FT-ICR Mass Spectrometry

Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1852 ◽  
Author(s):  
Wenjuan Zeng ◽  
Yanyan Zhang ◽  
Wei Zheng ◽  
Qun Luo ◽  
Juanjuan Han ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Cyclotron Resonance ◽  
Collision Induced Dissociation ◽  
Ion Cyclotron Resonance ◽  
Top Down ◽  
Binding Models ◽  
Cellular Dna ◽  
Ft Icr Ms ◽  
Ft Icr

The clinically widely-used anticancer drug, cisplatin, binds strongly to DNA as a DNA-damaging agent. Herein, we investigated the interaction of cisplatin with a 15-mer single-stranded C,T-rich oligodeoxynucleotide, 5′-CCTT4CTT7G8C9T10TCTCC-3′ (ODN15), using ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) in conjunction with tandem mass spectrometry (top-down MS). Top-down MS analysis with collision-induced dissociation (CID) fragmentation of the mono-platinated and di-platinated ODN15 provided abundant and informative Pt-containing or Pt-free a/[a − B], w and internal fragments, allowing the unambiguous identification of T4, T7, C9, and T10 as the platination sites on the cisplatin-ODN15 adducts. These results revealed that, in addition to the well-established guanine site, the unexpected thermodynamic binding of cisplatin to cytosine and thymine bases was also evident at the oligonucleotide level. Furthermore, the binding models of cisplatin with cytosine and thymine bases were built as the Pt coordinated to cytosine-N(3) and thymine-N(3) with displacement of the proton or tautomerization of thymine. These findings contribute to a better understanding of the mechanism of action of cisplatin and its preference for gene loci when the drug binds to cellular DNA, and also demonstrate the great potential and superiority of FT-ICR MS in studying the interactions of metallodrugs with large biomolecules.

Direct Imaging of Plant Metabolites in the Rhizosphere using Laser Desorption Ionization Ultra-high Resolution Mass Spectrometry

2021 ◽  
Author(s):  
Martin Lohse ◽  
Rebecca Haag ◽  
Thorsten Reemtsma ◽  
Oliver Lechtenfeld
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Organic Carbon ◽  
Laser Desorption ◽  
Mass Spectrometric ◽  
Laser Desorption Ionization ◽  
Plant Metabolites ◽  
Desorption Ionization ◽  
Ft Icr Ms ◽  
Ft Icr

<p>The rhizosphere is an important hotspot for microbial activity, organic carbon input, and carbon turnover in soils. The interplay of these rhizosphere components results in small scale gradients of organic molecules in the zone around a root. Mass spectrometric imaging (MSI) can reveal the spatial distribution of individual plant metabolites in the soil, which cannot be achieved using bulk analysis. Using non-fragmenting ionization techniques such as laser desorption ionization (LDI) allows for the detection of intact molecules without the need for labeling with e.g. fluorescent tags.</p><p>Direct MSI for the chemical imaging of intact molecules of the rhizosphere has been recognized as a still existing analytical gap. Here we present a novel method allowing mass spectrometric molecular rhizosphere imaging directly in a complex soil matrix.</p><p>Our novel approach consists of sampling the roots and the surrounding soil of <em>Zea mays </em>plants in either field- or lab-scale experiments using small metal cylinders. After excavation, the loam soil pellets were embedded in gelatin and cryosectioned to 100 µm sections. After selecting regions of interest on the soil section, the root and the soil surrounding the root was analysed using ultra-high resolution laser desorption ionization Fourier-transform ion cyclotron resonance mass spectrometry (LDI-FT-ICR-MS).</p><p>Given the large background of soil-derived organic carbon, the high mass resolution and sensitivity of FT-ICR-MS allow distinguishing root-derived molecules from soil organic matter based on their exact masses. We show that our method is capable to recover rhizosphere gradients of a dihexose (C<sub>12</sub>H<sub>22</sub>O<sub>11</sub>, e.g. sucrose, maltose) directly in the soil with a spatial resolution of 25 µm.</p><p>Molecular gradients for the dihexose showed a high abundance of this metabolite in the root and a strong depletion of the signal intensity within 150 µm from the root surface. Analysing several sections from the same soil pellet allowed to recover 3D molecular gradients from one root segment. Utilizing the potential to easily change the mass window a variety of potential metabolites can be analysed in the same region around the root. Thus the chemical diversity of potential root exudates can be revealed.</p><p>Our workflow enables the study of root-derived organic carbon with high spatial resolution directly in a soil context. For the first time, direct molecular imaging of the rhizosphere via LDI-FT-ICR-MS will allow for a non-target or targeted analysis of complex soil samples.</p><p>Visualizing the root structure via X-ray computed tomography in a soil sample before the embedding would enable a guided sampling approach to analyse molecular distributions at certain parts of the root. Moreover, the molecular LDI-MSI results could be correlated with elemental imaging via laser ablation – inductively coupled plasma – mass spectrometry directly at the same sample position - allowing for an even more detailed insight into chemical processes in the rhizosphere.</p>

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