Table 1. Marker bands in the TERS spectra of different insulin fibrils used for the identification of specific amino acids.

Experiment 1, tip 1, Figure S1	Experiment 2, tip 2, Figure 1	Experiment 3, tip 3, Figure 2	Experiment 4, tip 3, Figure 3	Assignment23
Wavenumber/cm−1
660, 671–673, 686–688, 698	657–667, 680	658–666, 682–693		cys–cys (CS)
780, 793–806	760–775	750–770, 78–787	795–799	cys–cys (CS)
832–835, 845–848, 865–868	830	820–827, 834–840	819–826	tyr (ring breathing)
1060–1065, 1081–1083	1060–1067	1067–1078	1066–1074	asn, gln (NH3+)
	1070–1080			lys34,35,36,43 (NH3+, add. to 1150 cm−1)
	1088–1094		1083–1090	arg36,43 (=NH2+, add. to 1170 cm−1)
1121–1128	1130–1140	1122–1130, 1140–1150	1139–1148	asn, gln (NH3+)
	1145–1153			lys34,35,36,43 (NH3+, add. to 1075 cm−1)
	1166–1170			arg35,36 (=NH2+, add. to 1090 cm−1)
1210–1216	1206–1209	1186–1191, 1196–1204	1198–1192	CH, tyr34 (CH, add. to 825/855 cm−1)
1230, 1260–1274, 1284–1290, 1290–1299	1219–1229, 1230–1237, 1240–1249, 1251–1259, 1260–1267, 1271–1277, 1294–1305	1210–1225, 1240–1247, 1271–1276, 1293–1311	1237–1250, 1263–1270, 1271–1277, 1293–1308	amide III, CH234,35,36,37
1638, 1644		1634–1648	1640–1650	amide I (α-helix/unordered)31