Dependence of the Nanoscale Composite Morphology of Fe3O4 Nanoparticle-Infused Lysozyme Amyloid Fibrils on Timing of Infusion: A Combined SAXS and AFM Study

Schroer M, Hu P, Tomasovicova N, Batkova M, Zakutanska K, Wu P, Kopcansky P, Molecules 26(16):4864 (2021) DOI

SASDM54 – LAF + P30 nanocomposite (NP added before fibrilization)

lysozyme amyloid fibril
Fe3O4 nanoparticles; nominal diameter 30 nm (hydrodynamic diameter)
MWexperimental 1 kDa
MWexpected 2 kDa
log I(s) 1.91×108 1.91×107 1.91×106 1.91×105
lysozyme amyloid fibril Fe3O4 nanoparticles; nominal diameter 30 nm (hydrodynamic diameter) small angle scattering data  s, nm-1
ln I(s)
lysozyme amyloid fibril Fe3O4 nanoparticles; nominal diameter 30 nm (hydrodynamic diameter) Guinier plot ln 1.91×108 Rg: 22.5 nm 0 (22.5 nm)-2 s2
(sRg)2I(s)/I(0)
lysozyme amyloid fibril Fe3O4 nanoparticles; nominal diameter 30 nm (hydrodynamic diameter) Kratky plot 1.104 0 3 sRg
p(r)
lysozyme amyloid fibril Fe3O4 nanoparticles; nominal diameter 30 nm (hydrodynamic diameter) pair distance distribution function Rg: 26.9 nm 0 Dmax: 95 nm

Data validation


Fits and models


log I(s)
 s, nm-1
lysozyme amyloid fibril Fe3O4 nanoparticles; nominal diameter 30 nm (hydrodynamic diameter) DAMMIN model

Synchrotron SAXS data from solutions of LAF + P30 nanocomposite (NP added before fibrilization) in 0.2 M glycine-HCl, 80 mM NaCl, pH 2.2 were collected on the EMBL P12 beam line at the PETRA III storage ring (Hamburg, Germany) using a Pilatus 6M detector at a sample-detector distance of 3 m and at a wavelength of λ = 0.123 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). at 20°C. 20 successive 0.050 second frames were collected. The data were normalized to the intensity of the transmitted beam and radially averaged; the scattering of the solvent-blank was subtracted.

LAF solution commenced with the dissolving of the hen egg white lysozyme (HEWL) powder in the buffer solution that consisted of 0.2 M glycine-HCl, with a pH of 2.2 and 80 mM NaCl, settling down at the concentration of 5 mg/mL. The buffer solution was conditioned at the acidic pH level of 2.2 for breaking down of the HEWL powder within a short period of time relative to the naturally occurring process. Theoretical SAXS profile computed by DAMMIX analysis of a concentration series from LAF and P30 nanoparticles (in air SAXS). SVD analysis showed the presence of a third component in the mixture, which was identified as this nanocomposite. Nanocomposite formed by addition of P30 nanoparticles BEFORE starting the LAF formation: LAF powder solution was doped with NP of volume concentrations (10 µL, 30 µL, 300 µL), and was afterwards heated for 2 h at 65 °C while being constantly stirred at 250 rounds per minute (rpm) to form the fibrillary nanocomposites (type-B process).

lysozyme amyloid fibril (LAF)
Mol. type   Protein
Organism   Gallus gallus
Olig. state   Unknown
Mon. MW   1 kDa
 
UniProt   P00698
Sequence   FASTA
 
Fe3O4 nanoparticles; nominal diameter 30 nm (hydrodynamic diameter) (P30)
Mol. type   Other
Olig. state   Monomer
Mon. MW   1 kDa
Chemical formula