. 2021 Feb 26;11(15):8899–8915. doi: 10.1039/d1ra00870f

Secondary structure composition from amide I curve-fitting analysis.

Strain/variant	Nonregular/coupling			Turn/α-helix			β-Sheet			Nonregular
Strain/variant	Frequency (cm⁻¹)	Width (cm⁻¹)	Area (%)	Frequency (cm⁻¹)	Width (cm⁻¹)	Area (%)	Frequency (cm⁻¹)	Width (cm⁻¹)	Area (%)	Frequency (cm⁻¹)	Width (cm⁻¹)	Area (%)
PBS-2N4R	1640	35	19	1658	25	26	1672	17	37	1686	25	18
Tris-2N4R	1640	37	22	1657	22	16	1670	16	29	1680	31	33
PBS-2N4R (RNA)	1635	15	5	1657	23	29	1670	16	45	1687	27	21
Hepes-2N4R	1640	39	25	1656	18	12	1670	18	41	1685	27	22
HEPES-0N3R	1640	40	22	1663	27	27	1671	16	37	1688	23	14
HEPES-K18	1640	36	17	1659	21	19	1671	15	50	1683	26	14
HEPES-P301S	1640	32	21	1658	21	22	1671	15	30	1683	27	27