The role of cysteine residues in the allosteric modulation of the chromophore phototransformations of biphotochromic fluorescent protein SAASoti

Abstract Biphotochromic fluorescent protein SAASoti contains five cysteine residues in its sequence and a V127T point mutation transforms it to the monomeric form, mSAASoti. These cysteine residues are located far from the chromophore and might control its properties only allosterically. The influen...

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Main Authors: A. V. Gavshina, N. K. Marynich, M. G. Khrenova, I. D. Solovyev, A. P. Savitsky
Format: Article
Language:English
Published: Nature Portfolio 2021-12-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-021-03634-9
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author A. V. Gavshina
N. K. Marynich
M. G. Khrenova
I. D. Solovyev
A. P. Savitsky
author_facet A. V. Gavshina
N. K. Marynich
M. G. Khrenova
I. D. Solovyev
A. P. Savitsky
author_sort A. V. Gavshina
collection DOAJ
description Abstract Biphotochromic fluorescent protein SAASoti contains five cysteine residues in its sequence and a V127T point mutation transforms it to the monomeric form, mSAASoti. These cysteine residues are located far from the chromophore and might control its properties only allosterically. The influence of individual, double and triple cysteine substitutions of mSAASoti on fluorescent parameters and phototransformation reactions (irreversible green-to-red photoconversion and reversible photoswitching) is studied. A set of mSAASoti mutant forms (C21N, C117S, C71V, C105V, C175A, C21N/C71V, C21N/C175A, C21N/C71G/C175A) is obtained by site-directed mutagenesis. We demonstrate that the C21N variant exists in a monomeric form up to high concentrations, the C71V substitution accelerates photoconversion to the red form and the C105V variant has the maximum photoswitching rate. All C175A-containing variants demonstrate different photoswitching kinetics and decreased photostability during subsequent switching cycles compared with other considered systems. Classical molecular dynamic simulations reveal that the F177 side chain located in the vicinity of the chromophore is considerably more flexible in the mSAASoti compared with its C175A variant. This might be the explanation of the experimentally observed slowdown the thermal relaxation rate, i.e., trans–cis isomerization of the chromophore in mSAASoti upon C175A substitution.
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spelling doaj.art-b565d92a74ff447493bf3a65236a18ee2022-12-21T18:45:09ZengNature PortfolioScientific Reports2045-23222021-12-0111111110.1038/s41598-021-03634-9The role of cysteine residues in the allosteric modulation of the chromophore phototransformations of biphotochromic fluorescent protein SAASotiA. V. Gavshina0N. K. Marynich1M. G. Khrenova2I. D. Solovyev3A. P. Savitsky4A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of SciencesA.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of SciencesA.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of SciencesA.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of SciencesA.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of SciencesAbstract Biphotochromic fluorescent protein SAASoti contains five cysteine residues in its sequence and a V127T point mutation transforms it to the monomeric form, mSAASoti. These cysteine residues are located far from the chromophore and might control its properties only allosterically. The influence of individual, double and triple cysteine substitutions of mSAASoti on fluorescent parameters and phototransformation reactions (irreversible green-to-red photoconversion and reversible photoswitching) is studied. A set of mSAASoti mutant forms (C21N, C117S, C71V, C105V, C175A, C21N/C71V, C21N/C175A, C21N/C71G/C175A) is obtained by site-directed mutagenesis. We demonstrate that the C21N variant exists in a monomeric form up to high concentrations, the C71V substitution accelerates photoconversion to the red form and the C105V variant has the maximum photoswitching rate. All C175A-containing variants demonstrate different photoswitching kinetics and decreased photostability during subsequent switching cycles compared with other considered systems. Classical molecular dynamic simulations reveal that the F177 side chain located in the vicinity of the chromophore is considerably more flexible in the mSAASoti compared with its C175A variant. This might be the explanation of the experimentally observed slowdown the thermal relaxation rate, i.e., trans–cis isomerization of the chromophore in mSAASoti upon C175A substitution.https://doi.org/10.1038/s41598-021-03634-9
spellingShingle A. V. Gavshina
N. K. Marynich
M. G. Khrenova
I. D. Solovyev
A. P. Savitsky
The role of cysteine residues in the allosteric modulation of the chromophore phototransformations of biphotochromic fluorescent protein SAASoti
Scientific Reports
title The role of cysteine residues in the allosteric modulation of the chromophore phototransformations of biphotochromic fluorescent protein SAASoti
title_full The role of cysteine residues in the allosteric modulation of the chromophore phototransformations of biphotochromic fluorescent protein SAASoti
title_fullStr The role of cysteine residues in the allosteric modulation of the chromophore phototransformations of biphotochromic fluorescent protein SAASoti
title_full_unstemmed The role of cysteine residues in the allosteric modulation of the chromophore phototransformations of biphotochromic fluorescent protein SAASoti
title_short The role of cysteine residues in the allosteric modulation of the chromophore phototransformations of biphotochromic fluorescent protein SAASoti
title_sort role of cysteine residues in the allosteric modulation of the chromophore phototransformations of biphotochromic fluorescent protein saasoti
url https://doi.org/10.1038/s41598-021-03634-9
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