SCN as a Local Probe of Protein Structural Dynamics

Fuente: arXiv
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Auteurs principaux: Aydin, Sena, Salehi, Seyedeh Maryam, Töpfer, Kai, Meuwly, Markus
Format: Preprint
Publié: 2024
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author Aydin, Sena
Salehi, Seyedeh Maryam
Töpfer, Kai
Meuwly, Markus
author_facet Aydin, Sena
Salehi, Seyedeh Maryam
Töpfer, Kai
Meuwly, Markus
contents The dynamics of lysozyme is probed by attaching -SCN to all alanine-residues. The 1-dimensional infrared spectra exhibit frequency shifts in the position of the maximum absorption by 4 cm$^{-1}$ which is consistent with experiments in different solvents and indicates moderately strong interactions of the vibrational probe with its environment. Isotopic substitution $^{12}$C $\rightarrow ^{13}$C leads to a red-shift by $-47$ cm$^{-1}$ which is consistent with experiments with results on CN-substituted copper complexes in solution. The low-frequency, far-infrared part of the protein spectra contain label-specific information in the difference spectra when compared with the wild type protein. Depending on the positioning of the labels, local structural changes are observed. For example, introducing the -SCN label at Ala129 leads to breaking of the $α-$helical structure with concomitant change in the far-infrared spectrum. Finally, changes in the local hydration of SCN-labelled Alanine residues as a function of time can be related to angular reorientation of the label. It is concluded that -SCN is potentially useful for probing protein dynamics, both in the high-frequency (CN-stretch) and far-infrared part of the spectrum.
format Preprint
id arxiv_https___arxiv_org_abs_2404_18879
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle SCN as a Local Probe of Protein Structural Dynamics
Aydin, Sena
Salehi, Seyedeh Maryam
Töpfer, Kai
Meuwly, Markus
Chemical Physics
The dynamics of lysozyme is probed by attaching -SCN to all alanine-residues. The 1-dimensional infrared spectra exhibit frequency shifts in the position of the maximum absorption by 4 cm$^{-1}$ which is consistent with experiments in different solvents and indicates moderately strong interactions of the vibrational probe with its environment. Isotopic substitution $^{12}$C $\rightarrow ^{13}$C leads to a red-shift by $-47$ cm$^{-1}$ which is consistent with experiments with results on CN-substituted copper complexes in solution. The low-frequency, far-infrared part of the protein spectra contain label-specific information in the difference spectra when compared with the wild type protein. Depending on the positioning of the labels, local structural changes are observed. For example, introducing the -SCN label at Ala129 leads to breaking of the $α-$helical structure with concomitant change in the far-infrared spectrum. Finally, changes in the local hydration of SCN-labelled Alanine residues as a function of time can be related to angular reorientation of the label. It is concluded that -SCN is potentially useful for probing protein dynamics, both in the high-frequency (CN-stretch) and far-infrared part of the spectrum.
title SCN as a Local Probe of Protein Structural Dynamics
topic Chemical Physics
url https://arxiv.org/abs/2404.18879