Mass Determination of Entire Amyloid Fibrils by Using Mass Spectrometry

Abstract

Amyloid fibrils are self-assembled protein structures with important roles in biology (either pathogenic or physiological), and are attracting increasing interest in nanotechnology. However, because of their high aspect ratio and the presence of some polymorphism, that is, the possibility to adopt various structures, their characterization is challenging and basic information such as their mass is unknown. Here we show that charge-detection mass spectrometry, recently developed for large self-assembled systems such as viruses, provides such information in a straightforward manner.

The aerosol impact spectrometer: a versatile platform for studying the velocity dependence of nanoparticle-surface impact phenomena

“…The image charge waveform also yields the particle time-of-flight (TOF) and velocity through the pickup providing the mass-to-charge ratio for fixed energy particles [15]. This method has been used in accelerator experiments since at least 1960 [9], and with the increasing interest in studies of massive biomolecules, cells and nanoparticles it has seen more recent applications in mass spectrometry measurements [16][17][18][19][20][21][22][23][24], with the state of the art recently described by Keifer and Jarrold [25]. In our own laboratory, we make use of a variant of this approach, applying a charge-pickup electrode in an electrostatic fast-ion beam trap to monitor the ion density oscillating in the trap and carry out Fourier-transform (FT) mass spectrometry on ensembles of molecular ions [26,27].…”

Resolving heterogeneous high-mass macromolecular machineries by Orbitrap-based single particle charge detection mass spectrometry

“…An attractive alternative may come from measuring one particle (or ion) at a time, thereby avoiding the problematic convolution of signals that stem from insufficient resolving power [17][18][19][20][21][22][23][24][25][26][27] . When such single-particle detection approaches can be combined with an independent measure of the charge of ions, or when masses can be estimated using entirely different physical principles that circumvent the need to work with multiply charged ions, this opens up the door to bona fide single-particle mass spectrometry measurements.…”

“…The mass of the impacting particle can be calculated directly from the frequency shift that the resonator experiences 19,[23][24][25] . In CD-MS, the mass is calculated by measuring the m/z ratio and charge separately, typically by oscillating the particle in a cone trap through a conductive detection tube 17,26,27 . Knowing the ion energy, the charge can be determined from the pulse amplitude of the image current induced by the particle passing through and the m/z can be derived from the frequency of the oscillation.…”

Interprotein Electron Transfer between FeS‐Protein Nanowires and Oxygen‐Tolerant NiFe Hydrogenase

“…[1][2][3][4][5][6][7][8] Ad irect electron transfer (DET) between the enzymes and electrodes is possible and can be effective for functional biofuel cells. [13] This prion domain serves as at emplate for ar edox domain ( Figure 1A), both domains being associated within achimeric protein. However,M ET induces the use of immobilized redox mediators which can be highly complicated to synthesize or even toxic.…”

“…[12] Thedesign of these nanowires is based on the self-assembly of ap rion domain into amyloid fibers,w ith ad iameter of 3nm and an aspect ratio of 4000. [13] This prion domain serves as at emplate for ar edox domain ( Figure 1A), both domains being associated within achimeric protein. Genes coding for the prion domain of HET-s (from Podospora anserina) and for rubredoxin (Rd) from Methanococcus voltae were fused and cloned in E. coli to express the chimeric protein Rd-HET.…”