Amyloid fibrils

Figures & data

Figure 1 Isolated amyloid fibrils composed of Aα chain fragment of fibrinogen (a) stained with Congo red and visualized by light microscopy and (b) between crossed polars, showing characteristic apple-green birefringence. Figure adapted from reference 83.

Figure 2 Synthetic amyloid fibrils made from Aβ peptide (A) electron micrograph showing long, straight, unbranching fibrils. (B) X-ray fiber diffraction pattern from partially aligned amyloid fibrils showing the characteristic “cross-β” diffraction pattern. (C) The structure of the Aβ amyloid fibril interpreted from ssNMR data,67 showing the top view of the fiber (i and ii) with side chains (i), showing the importance of side chain packing with in the fiber and as a cartoon (ii). The side view (iii) revealing the β-strands running perpendicular to the fiber axis.

Figure 3 Models of mature protein fibrils based on Small-Angle X-ray scattering solution data. (A) Human alpha-synuclein fibrils and (B) human insulin fibrils.69 The results suggest that insulin fibrils (B) are formed of three intertwining protofibrils, whereas a-synuclein fibril (A) consist of only one protofibril. Each protofibril is assumed to consist of two intertwining protofilaments. Four and three repeating units are shown for alpha-synuclein and insulin respectively.

Figure 4 Amyloid-like fibers for bionanotechnology. (A) Nanowires based on the N-terminal region of the yeast prion, Sup35. Nanogold was covalently linked to the engineered cysteine residues in the protein and conjugate colloidal gold and silver particles were associated along the fibers to form wires,80 (B) assembly of diphenylalanine to form nanotubes that can be filled with silver to make nanowires.82

Table 1 Some amyloidoses and their respective precursors and amyloid-ogenic proteins

Disease	Precursor protein	Amyloid protein
Alzheimer's disease	Amyloid precursor protein	Aβ peptides
Atrial amyloidosis	Atrial natriuretic factor (ANF)	Amyloid ANF
Spongiform encephalopathies	Prion protein (PrPc)	PrPsc
Primary systemic amyloidosis	Immunoglobulin light and heavy chains	AL and AH
Senile systemic amyloidosis	Wild-type transthyretin	ATTR
Haemodialysis-related amyloidosis	β2-microglobulin	Aβ2M
Hereditary nonneuropathic systemic amyloidosis	Lysozyme	ALys
Type II diabetes	Pro-IAPP	IAPP or “amylin”
Injection-localized amyloidosis	Insulin	AIns
Secondary systemic amyloidosis	(Apo) serum amyloid A	Serum amyloid A
Hereditary cerebral amyloid angiopathy	Cystatin C	ACys
Finnish hereditary systemic amyloidosis	Gelsolin	AGel
Familial amyloid polyneuropathy I	Transthyretin variants	ATTR
Familial amyloid polyneuropathy II	Apolipoprotein A1	AApoA1
Ageing pituitary, prolactinomas	Prolactin	APro
Familial amyloidosis	Fibrinogen αA-chain	AFib
British familial dementia	Amyloid Bri Precursor Protein	ABri

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