Ion mobility unlocks the photofragmentation mechanism of Retinal protonated Schiff base

NJA Coughlan; BD Adamson; KJ Catani; U Wille; EJ Bieske

Journal article

Ion mobility unlocks the photofragmentation mechanism of Retinal protonated Schiff base

NJA Coughlan, BD Adamson, KJ Catani, U Wille, EJ Bieske

Journal of Physical Chemistry Letters | AMER CHEMICAL SOC | Published : 2014

DOI: 10.1021/jz501407n

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Abstract

Retinal protonated Schiff base (RPSB) is a key molecular component of biological photoreceptors and bacterial photosynthetic structures, where its action involves photoisomerization around bonds in the polyene chain. In a vacuum environment, collisional activation or exposure to visible light causes the RPSB molecule to disintegrate, producing charged molecular fragments with m/z = 248 Da that cannot be formed by simple cleavage of the polyene chain. Photofragments resulting from laser excitation of RPSB at a wavelength of 532 nm are analyzed in an ion mobility mass spectrometer (IMMS) and found to be the protonated Schiff base of β-ionone. Density functional theory calculations at the M06-2..

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University of Melbourne Researchers

Uta Wille Author

Evan Bieske Author

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Funding Acknowledgements

This research was supported under the Australian Research Council's Discovery Project funding scheme (Project Numbers DP110100312 and DP120100100). The computations were supported by the National Computational Merit Allocation Scheme (Project m88). We thank Professor Matthew Bush for providing a modified version of the Mobcal code with N<INF>2</INF> collision parameters described in ref 12, Luke Gamon for assistance with synthesis and collection of GC-MS data for the protonated Schiff base of beta-ionone, and Sioe See Volaric for assistance with collection of LC-MS data.