Effect of molecular dynamics and internal water contact on the photophysical properties of red pH sensitive proteins

Franz-Josef Schmitt; Amna Shah Mehmood; Christian Tüting; Hoang Trong Phan; Fabian Rieder; Farzin Ghane Golmohamadi; Jan Laufer

doi:10.1117/12.3017171

20 June 2024 Effect of molecular dynamics and internal water contact on the photophysical properties of red pH sensitive proteins

Franz-Josef Schmitt, Amna Shah Mehmood, Christian Tüting, Hoang Trong Phan, Fabian Rieder, Farzin Ghane Golmohamadi, Jan Laufer

Author Affiliations +

Proceedings Volume PC13006, Biomedical Spectroscopy, Microscopy, and Imaging III; PC130060T (2024) https://doi.org/10.1117/12.3017171
Event: SPIE Photonics Europe, 2024, Strasbourg, France

Abstract

This study analyses the pH-dependent time resolved fluorescence of mCardinal and mNeptune, two red-shifted fluorescent proteins with applications in biomedical imaging. We utilized molecular dynamics (MD) simulations to illuminate the influence of water molecules on the proteins´ photophysical properties. In mCardinal, the average fluorescence lifetime markedly rises from 0.95 ns at pH 7.0 to 1.25 ns at pH 5.5. Conversely, mNeptune exhibits a constant fluorescence lifetime, showing no pH sensitivity. Through Decay-Associated Spectra and MD simulations, we correlated mCardinal’s pH-induced lifetime changes with its molecular properties. Despite both proteins being equally stabilized by hydrogen bonds, mCardinal’s chromophore formed more water contacts than mNeptune’s. Additionally, the chromophore’s interactions with specific amino acids varied between the two proteins, suggesting distinct differences in the excited state proton transfer as a crucial mechanism for pH sensitivity.

Conference Presentation

Citation Download Citation

Franz-Josef Schmitt, Amna Shah Mehmood, Christian Tüting, Hoang Trong Phan, Fabian Rieder, Farzin Ghane Golmohamadi, and Jan Laufer "Effect of molecular dynamics and internal water contact on the photophysical properties of red pH sensitive proteins", Proc. SPIE PC13006, Biomedical Spectroscopy, Microscopy, and Imaging III, PC130060T (20 June 2024); https://doi.org/10.1117/12.3017171

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