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Updated: Jul 11, 2025

Chemical Modification of the Tryptophan Residue in a Recombinant Ca2+-ATPase N-domain for Studying Tryptophan-ANS FRET
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Chemical Modification of the Tryptophan Residue in a Recombinant Ca2+-ATPase N-domain for Studying Tryptophan-ANS FRET

Published on: October 9, 2021

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Red edge excitation shift spectroscopy is highly sensitive to tryptophan composition

Annmaree K Warrender1, Jolyn Pan2, Chris Pudney3

  • 1Te Huataki Waiora School of Health, University of Waikato, Hamilton, New Zealand.

Journal of the Royal Society, Interface
|November 7, 2023
PubMed

Red edge excitation shift (REES) spectroscopy relies on the unique emission profiles of fluorophore-solvent interactions to profile protein molecular dynamics. Recently, we reported the use of REES to compare the stability of 32 polymorphic IgG antibodies natively containing tryptophan reporter fluorophores. Here, we expand on this work to investigate the sensitivity of REES to variations in tryptophan content using a subset of IgG3 antibodies containing arginine to tryptophan polymorphisms. Structural analysis revealed that the additional tryptophan residues were situated in highly solvated environments. Subsequently, REES showed clear differences in fluorescence emission profiles when compared with the unmutated variants, thereby limiting direct comparison of their structural dynamics. These findings highlight the exquisite sensitivity of REES to minor variations in protein structure and tryptophan composition.

Keywords:
antibodiesprotein dynamicsprotein stabilityred edge excitation shifttryptophan fluorescence

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