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Vibronic structure in the far-UV electronic circular dichroism spectra of proteins

Li, Zhuo; Robinson, David; Hirst, Jonathan

Authors

Zhuo Li

David Robinson



Abstract

The Franck–Condon effect is considered and the vibrational structure of the πnbπ* transition of the peptide backbone is incorporated into matrix method calculations of the electronic circular dichroism (CD) spectra of proteins in the far-ultraviolet. We employ the state-averaged CASPT2 method to calculate the ground and πnbπ* excited state geometries and frequencies of N-methylacetamide (NMA), which represents the peptide chromophore. The results of these calculations are used to incorporate vibronic levels of the excited states into the matrix method calculation. The CD spectra of a set of 49 proteins, comprising a range of structural types, are calculated to assess the influence of the vibrational structure. The calculated spectra of α-helical proteins are better resolved using the vibronic parameters and correlation between the experimental and the calculated intensity of less regular β structure proteins improves over most wavelengths in the far-UV. No obvious improvement is observed in the calculated spectra of regular β-sheet proteins. Our high-level ab initio calculations of the vibronic structure of the πnbπ* transition in NMA have provided some further insight into the physical origins of the nature of protein CD spectra in the far-UV.

Citation

Li, Z., Robinson, D., & Hirst, J. (2015). Vibronic structure in the far-UV electronic circular dichroism spectra of proteins. Faraday Discussions, 177, 329-344. doi:10.1039/c4fd00163j

Journal Article Type Article
Acceptance Date Nov 5, 2014
Online Publication Date Jan 21, 2015
Publication Date Apr 1, 2015
Deposit Date Sep 12, 2018
Print ISSN 1359-6640
Electronic ISSN 1364-5498
Publisher Royal Society of Chemistry
Peer Reviewed Peer Reviewed
Volume 177
Pages 329-344
DOI https://doi.org/10.1039/c4fd00163j
Public URL https://nottingham-repository.worktribe.com/output/1107931
Publisher URL https://pubs.rsc.org/en/Content/ArticleLanding/2015/FD/C4FD00163J#!divAbstract
PMID 00035303