Table 2.

IR marker bands of abnormal protein aggregation.

Marker Band of the Aggregation [cm−1]	Assignment	Peptide		Reference
amide I (1700-1600 cm−1)
1695-1685/1633-1623	antiparallel β-sheet	amyloid β1-42	oligomers	[40,41]
		amyloid β1-40		[42,43,44]
		α-synuclein		[28,47,48]
		PrP82–146		[51]
1693-1685/1623–1613	antiparallel β-sheet	amyloid β11-28 fragment and its mutants in 21-23 position		[31]
1692/1620	antiparallel β-sheet	HET218–289		[55]
1691/1630	antiparallel β-sheet	Aβ 42CC oligomers/protofibrils		[32]
1688/1620	antiparallel β-sheet	human lysozyme, oligomers		[29]
1686/1616	antiparallel β-sheet	transthyretin (TTR) soluble aggregates		[52]
1686/1614	antiparallel β-sheet	hen egg white lysozyme (HEWL)		[56]
1684/1616		β2-microglobulin (short curved structures)		[54]
1684/1612	antiparallel β-sheet	SH3 domain, amorphous aggregates, non-fibrilar		[57]
1683/1612 ↑→	antiparallel β-sheet	insulin	oligomer	[39]
1678-1670	β-turns	amyloid β11-28 fragment and its mutants in 21-23 position		[31]
1670	β-turns	amyloid β1-42	oligomers and fibrils	[40]
		α-synuclein		[28]
1669	β-turns	HET218–289		[55]
1667-1661	310-helix	E22K and A21G mutants of Aβ(11-28) fragment		[31]
1664	β-turns	SH3 fibrils/pepsin digested		[57]
1660-1650	random coil and/or helical structures	amyloid β1-42	oligomers and fibrils	[40]
		α-synuclein		[28]
1659-1652	α-helix	amyloid β11-28 fragment and its mutants in 21-23 position		[31]
1658	Turns	human lysozyme	monomers, oligomers, fibrils	[29]
1655	random coil	HET218–289		[55]
1649	unstructured	SH3 amorphous aggregates		[57]
1648-1639	random coil	amyloid β11-28 fragment and its mutants in 21-23 position		[31]
1648	random coil	PrP82–146		[51]
1644-1641	disordered/loops	human lysozyme	oligomers, fibrils	[29]
1641	disordered structures	SH3 fibrils/pepsin digested		[57]
1635-1624	β-sheet	amyloid β11-28 fragment and its mutants in 21-23 position		[31]
1633	parallel β-sheet	Sup35 crystals, prion-like		[58]
1630	parallel β-sheets	HET218–289		[55]
1630-1623	parallel β-sheet	amyloid β1-42	fibrils	[40,41]
		amyloid β1-40		[42,43,44]
1630-1614	parallel β-sheet	human lysozyme	fibrils	[29]
1628	parallel β-sheet	α-synuclein	fibrils	[28]
1626 ↑	parallel β-sheet	PrP82–146	fibrils	[51]
1626 ↑→	parallel β-sheet	insulin	fibrils	[39]
1625	parallel β-sheet	transthyretin (TTR)	fibrils	[52]
1620-1618		β2-microglobulin, fibrils		[54]
1620-1600	β-sheets	hen egg white lysozyme (HEWL)		[56]
1618 ←	parallel β-sheet	SH3 fibrils/pepsin digested		[57]

↑ increase in intensity, ← shift towards higher wavenumbers after aggregation, → shift towards lower wavenumbers after aggregation.