Alzheimer's Disease Aβ Peptide Fragment 10–30 Forms a Spectrum of Metastable Oligomers with Marked Preference for N to N and C to C Monomer Termini Proximity

Ion Mobility Separation Coupled with MS Detects Two Structural States of Alzheimer's Disease Aβ1–40 Peptide Oligomers

“…For instance, it has been shown that monomers in a dimer retain a parallel register and not the antiparallel. 22 Therefore, a β-structure of oligomeric species is likely. We have based our molecular models on known experimental constraints, and they show good correlation with IMS data without the necessity to adjust additional parameters, such as dimeric Ω value (see discussion at p. 328 in Ref.…”

“…22 For selective cleavage, the ProTEV cleavage site 31 (Glu-Asn-Leu-Tyr-Phe-Gln) was inserted into the leader sequence, ahead of the Aβ1-40 sequence. The transformed Escherichia coli strain BL21(DE3) cells were grown from overnight cultures in LB medium supplemented with kanamycin (33 μg/ml) at 37°C to A 600 of 1.0.…”

“…IMS resolves species according to their collisional cross section (Ω), providing a means to resolve isobaric species and to measure and accurately determine their Ω. IMS-MS has recently been used to study the oligomerization of β 2 -microglobulin. 21 In our previous work 22 on Aβ (truncated version) spanning residues 10 through 30 (Aβ10-30), we have shown in an MS experiment that in aqueous solution and at neutral pH, a dynamic equilibrium between Aβ10-30 monomers and a set of oligomers can be observed. Here, we extend our previous work by analyzing the oligomeric forms of a full-length version of Aβ (Aβ1-40) by IMS-MS. We also construct three families of structural models that provide excellent correlation between theoretical and experimental Ω.…”

The use of mass spectrometry to study amyloid‐β peptides

“…Other MS studies carried out on shorter Ab models have yielded more structural information on Ab fibrillation. In this way, it was possible to identify which amino acid residues of Ab participate in interstrand pairing and initiate fibrillogenesis (Li & Fenselau, 2004), and to assess that Ab has a marked tendency for a parallel strand orientation that is strongly preferred over an antiparallel one (Jablonowska et al, 2004). HDX/MS has also been applied to investigate the different aggregation structures of Ab1-40, to highlight large differences between mature fibrils and protofibrils, and to demonstrate the possibility to rapidly and efficiently convert Ab1-40 monomers into clusters of protofibrils by the addition of some compounds such as calmidazolium chloride (Williams et al, 2005).…”

Elongated oligomers in β 2 -microglobulin amyloid assembly revealed by ion mobility spectrometry-mass spectrometry

“…ESI-MS is ideally suited to the characterization of macromolecular protein complexes (5)(6)(7)(8), and ion mobility spectrometry (IMS) coupled to ESI-MS (ESI-IMS-MS) has enabled the separation of copopulated protein conformers (9-13) and calculation of their individual collision cross-sections (Ωs) in a single experiment (14 and 15). In the context of amyloid fibril formation, ESI-MS has been applied to monitor monomer depletion during fibril assembly (16)(17)(18) and to identify transient oligomeric species (11,16,19,20) for a number of amyloidogenic proteins, whereas ESI-IMS-MS has been employed to measure the Ωs of transient intermediates populated during the assembly of Aβ 40 and Aβ 42 (11).…”