Broadband Multidimensional Spectroscopy Identifies the Amide II Vibrations in Silkworm Films
We used two-dimensional infrared spectroscopy to disentangle the broad infrared band in the amide II vibrational regions of <i>Bombyx mori</i> native silk films, identifying the single amide II modes and correlating them to specific secondary structure. Amide I and amide II modes have a...
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| Format: | Article |
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MDPI AG
2022-09-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/27/19/6275 |
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| author | Adam S. Chatterley Peter Laity Chris Holland Tobias Weidner Sander Woutersen Giulia Giubertoni |
| author_facet | Adam S. Chatterley Peter Laity Chris Holland Tobias Weidner Sander Woutersen Giulia Giubertoni |
| author_sort | Adam S. Chatterley |
| collection | DOAJ |
| description | We used two-dimensional infrared spectroscopy to disentangle the broad infrared band in the amide II vibrational regions of <i>Bombyx mori</i> native silk films, identifying the single amide II modes and correlating them to specific secondary structure. Amide I and amide II modes have a strong vibrational coupling, which manifests as cross-peaks in 2D infrared spectra with frequencies determined by both the amide I and amide II frequencies of the same secondary structure. By cross referencing with well-known amide I assignments, we determined that the amide II (N-H) absorbs at around 1552 and at 1530 cm<sup>–1</sup> for helical and β-sheet structures, respectively. We also observed a peak at 1517 cm<sup>−1</sup> that could not be easily assigned to an amide II mode, and instead we tentatively assigned it to a Tyrosine sidechain. These results stand in contrast with previous findings from linear infrared spectroscopy, highlighting the ability of multidimensional spectroscopy for untangling convoluted spectra, and suggesting the need for caution when assigning silk amide II spectra. |
| first_indexed | 2024-03-09T21:25:44Z |
| format | Article |
| id | doaj.art-77ea3c9d5d534c30b500a730ee825044 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-09T21:25:44Z |
| publishDate | 2022-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-77ea3c9d5d534c30b500a730ee8250442023-11-23T21:08:37ZengMDPI AGMolecules1420-30492022-09-012719627510.3390/molecules27196275Broadband Multidimensional Spectroscopy Identifies the Amide II Vibrations in Silkworm FilmsAdam S. Chatterley0Peter Laity1Chris Holland2Tobias Weidner3Sander Woutersen4Giulia Giubertoni5Department of Chemistry, Aarhus University, 8000 Aarhus C, DenmarkDepartment of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD, UKDepartment of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD, UKDepartment of Chemistry, Aarhus University, 8000 Aarhus C, DenmarkVan ‘t Hoff Institute for Molecular Sciences, University of Amsterdam, 1098 XH Amsterdam, The NetherlandsVan ‘t Hoff Institute for Molecular Sciences, University of Amsterdam, 1098 XH Amsterdam, The NetherlandsWe used two-dimensional infrared spectroscopy to disentangle the broad infrared band in the amide II vibrational regions of <i>Bombyx mori</i> native silk films, identifying the single amide II modes and correlating them to specific secondary structure. Amide I and amide II modes have a strong vibrational coupling, which manifests as cross-peaks in 2D infrared spectra with frequencies determined by both the amide I and amide II frequencies of the same secondary structure. By cross referencing with well-known amide I assignments, we determined that the amide II (N-H) absorbs at around 1552 and at 1530 cm<sup>–1</sup> for helical and β-sheet structures, respectively. We also observed a peak at 1517 cm<sup>−1</sup> that could not be easily assigned to an amide II mode, and instead we tentatively assigned it to a Tyrosine sidechain. These results stand in contrast with previous findings from linear infrared spectroscopy, highlighting the ability of multidimensional spectroscopy for untangling convoluted spectra, and suggesting the need for caution when assigning silk amide II spectra.https://www.mdpi.com/1420-3049/27/19/6275(2D)-infrared spectroscopyamide IIsecondary structure<i>Bombyx mori</i> native silk films |
| spellingShingle | Adam S. Chatterley Peter Laity Chris Holland Tobias Weidner Sander Woutersen Giulia Giubertoni Broadband Multidimensional Spectroscopy Identifies the Amide II Vibrations in Silkworm Films Molecules (2D)-infrared spectroscopy amide II secondary structure <i>Bombyx mori</i> native silk films |
| title | Broadband Multidimensional Spectroscopy Identifies the Amide II Vibrations in Silkworm Films |
| title_full | Broadband Multidimensional Spectroscopy Identifies the Amide II Vibrations in Silkworm Films |
| title_fullStr | Broadband Multidimensional Spectroscopy Identifies the Amide II Vibrations in Silkworm Films |
| title_full_unstemmed | Broadband Multidimensional Spectroscopy Identifies the Amide II Vibrations in Silkworm Films |
| title_short | Broadband Multidimensional Spectroscopy Identifies the Amide II Vibrations in Silkworm Films |
| title_sort | broadband multidimensional spectroscopy identifies the amide ii vibrations in silkworm films |
| topic | (2D)-infrared spectroscopy amide II secondary structure <i>Bombyx mori</i> native silk films |
| url | https://www.mdpi.com/1420-3049/27/19/6275 |
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