Peak assignments for proteinsa.
| Contributing group | Frequency (cm−1) | Assignment |
|---|---|---|
| Backbone | 1670–1680 | β turn, random structure, Amide I26 |
| 1660–1670 | β sheet, Amide I34 | |
| 1650–1655 | α helices, Amide I35 | |
| 1630–1635 | β sheet, Amide I36,37 | |
| 1550 | Amide II25 | |
| 1270–1300 | α helices, Amide III38 | |
| 1240–1250 | Random structure, Amide III39 | |
| 1230–1240 | β sheet, Amide III39 | |
| Disulphide | 505–515 | GGG conformation40,41 |
| 520–530 | GGT, GTG conformation40,41 | |
| 540–545 | TGT conformation40,41 | |
| Side chain | 1615, 830, 643 | Tyrosine42 |
| 850/830 | Hydrogen bonding state of tyrosine;43 | |
| 1550, 1010, 750 | Tryptophan44 | |
| 880/1361 | Ring environment of indole ring of tryptophan45 | |
| 1360/1340 | Hydrophobicity marker for tryptophan44 | |
| 1609, 1205, 1003 | Phenylalanine46 |
a
α: alpha helices, β: beta sheets, GGG: gauche–gauche–gauche, GGT: gauche–gauche–trans, GTG: gauche–trans–gauche, TGT: trans–gauche–trans.