Synthesis of 5‐Cyano‐Tryptophan as a Two‐Dimensional Infrared Spectroscopic Reporter of Structure. Issue 25 (29th May 2018)

• Record Type: Journal Article
• Authors: Chalyavi, Farzaneh; Gilmartin, Philip H.; Schmitz, Andrew J.; Fennie, Michael W.; Tucker, Matthew J.
• Is Part Of: Angewandte Chemie international edition. Volume 57:Issue 25(2018)
• Page Start: 7528
• Page End: 7532
• Publication Date: 2018-05-29
• Subjects: amino acids -- conformation analysis -- IR spectroscopy -- nitrile -- peptides; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201803849
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: A concise synthesis of protected 5‐cyano‐l ‐tryptophan (Trp5CN ) has been developed for 2D IR spectroscopic investigations within either peptides or proteins. To assess the potential of differently substituted cyano‐tryptophans, several model cyano‐indole systems were characterized using IR spectroscopy. Upon assessment of their spectroscopic properties, Trp5CN was integrated into a model peptide sequence, Trp5CN ‐Gly‐Phe4CN, to elucidate its structure. This peptide demonstrates the capability of this probe to capture structural information by 2D IR spectroscopy. The 2D IR spectrum of the peptide in water was simulated to reveal a unique spectral signature resulting from the presence of dipolar coupling. The coupling strength between cyano labels was determined to be 1.4 cm −1 by matching the slopes along the max contour for the simulated and experimental spectrum. Using transition dipole coupling, a distance between the two probes of 13 Å was calculated. Abstract : Good vibrations : The synthesis of protected 5‐cyano‐l ‐tryptophan was developed for two‐dimensional infrared (2D IR) spectroscopic investigations within a model peptide, Trp5CN ‐Gly‐Phe4CN, for which vibrational coupling between the cyano labels was captured. The coupling strength between cyano labels was determined to be 1.4 cm −1 . By using transition dipole coupling a distance of 13 Å between the two probes was calculated.