Encapsulation into complex coacervate core micelles promotes EGFP dimerization

A. Nolles, N.J.E. Van Dongen, A.H. Westphal, A.J.W.G. Visser, J.M. Kleijn, W.J.H. Van Berkel, J.W. Borst*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Scopus)

Abstract

Complex coacervate core micelles (C3Ms) are colloidal structures useful for encapsulation of biomacromolecules. We previously demonstrated that enhanced green fluorescent protein (EGFP) can be encapsulated into C3Ms using the diblock copolymer poly(2-methyl-vinyl-pyridinium)41-b-poly(ethylene-oxide)205. This packaging resulted in deviating spectroscopic features of the encapsulated EGFP molecules. Here we show that for monomeric EGFP variant (mEGFP) micellar encapsulation affects the absorption and fluorescence properties to a much lesser extent, and that changes in circular dichroism characteristics are specific for encapsulated EGFP. Time-resolved fluorescence anisotropy of encapsulated (m)EGFP established the occurrence of homo-FRET (Förster resonance energy transfer) with larger transfer correlation times in the case of EGFP. Together, these findings support that EGFP dimerizes whereas the mEGFP mainly remains as a monomer in the densely packed C3Ms. We propose that dimerization of encapsulated EGFP causes a reorientation of Glu222, resulting in a pKa shift of the chromophore, which is fully reversible after release of EGFP from the C3Ms at a high ionic strength.
Original languageEnglish
Pages (from-to)11380-11389
JournalPhysical Chemistry Chemical Physics
Volume19
Issue number18
DOIs
Publication statusPublished - 2017

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Dimerization
Micelles
dimerization
Encapsulation
micelles
proteins
Fluorescence
enhanced green fluorescent protein
fluorescence
Chromophores
ethylene oxide
Polyethylene oxides
Ionic strength
packaging
Energy transfer
chromophores
dichroism
Block copolymers
retraining
copolymers

Cite this

@article{4069558da2bd4557904e6cff5a4abb78,
title = "Encapsulation into complex coacervate core micelles promotes EGFP dimerization",
abstract = "Complex coacervate core micelles (C3Ms) are colloidal structures useful for encapsulation of biomacromolecules. We previously demonstrated that enhanced green fluorescent protein (EGFP) can be encapsulated into C3Ms using the diblock copolymer poly(2-methyl-vinyl-pyridinium)41-b-poly(ethylene-oxide)205. This packaging resulted in deviating spectroscopic features of the encapsulated EGFP molecules. Here we show that for monomeric EGFP variant (mEGFP) micellar encapsulation affects the absorption and fluorescence properties to a much lesser extent, and that changes in circular dichroism characteristics are specific for encapsulated EGFP. Time-resolved fluorescence anisotropy of encapsulated (m)EGFP established the occurrence of homo-FRET (F{\"o}rster resonance energy transfer) with larger transfer correlation times in the case of EGFP. Together, these findings support that EGFP dimerizes whereas the mEGFP mainly remains as a monomer in the densely packed C3Ms. We propose that dimerization of encapsulated EGFP causes a reorientation of Glu222, resulting in a pKa shift of the chromophore, which is fully reversible after release of EGFP from the C3Ms at a high ionic strength.",
author = "A. Nolles and {Van Dongen}, N.J.E. and A.H. Westphal and A.J.W.G. Visser and J.M. Kleijn and {Van Berkel}, W.J.H. and J.W. Borst",
year = "2017",
doi = "10.1039/c7cp00755h",
language = "English",
volume = "19",
pages = "11380--11389",
journal = "Physical Chemistry Chemical Physics",
issn = "1463-9076",
publisher = "Royal Society of Chemistry",
number = "18",

}

Encapsulation into complex coacervate core micelles promotes EGFP dimerization. / Nolles, A.; Van Dongen, N.J.E.; Westphal, A.H.; Visser, A.J.W.G.; Kleijn, J.M.; Van Berkel, W.J.H.; Borst, J.W.

In: Physical Chemistry Chemical Physics, Vol. 19, No. 18, 2017, p. 11380-11389.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Encapsulation into complex coacervate core micelles promotes EGFP dimerization

AU - Nolles, A.

AU - Van Dongen, N.J.E.

AU - Westphal, A.H.

AU - Visser, A.J.W.G.

AU - Kleijn, J.M.

AU - Van Berkel, W.J.H.

AU - Borst, J.W.

PY - 2017

Y1 - 2017

N2 - Complex coacervate core micelles (C3Ms) are colloidal structures useful for encapsulation of biomacromolecules. We previously demonstrated that enhanced green fluorescent protein (EGFP) can be encapsulated into C3Ms using the diblock copolymer poly(2-methyl-vinyl-pyridinium)41-b-poly(ethylene-oxide)205. This packaging resulted in deviating spectroscopic features of the encapsulated EGFP molecules. Here we show that for monomeric EGFP variant (mEGFP) micellar encapsulation affects the absorption and fluorescence properties to a much lesser extent, and that changes in circular dichroism characteristics are specific for encapsulated EGFP. Time-resolved fluorescence anisotropy of encapsulated (m)EGFP established the occurrence of homo-FRET (Förster resonance energy transfer) with larger transfer correlation times in the case of EGFP. Together, these findings support that EGFP dimerizes whereas the mEGFP mainly remains as a monomer in the densely packed C3Ms. We propose that dimerization of encapsulated EGFP causes a reorientation of Glu222, resulting in a pKa shift of the chromophore, which is fully reversible after release of EGFP from the C3Ms at a high ionic strength.

AB - Complex coacervate core micelles (C3Ms) are colloidal structures useful for encapsulation of biomacromolecules. We previously demonstrated that enhanced green fluorescent protein (EGFP) can be encapsulated into C3Ms using the diblock copolymer poly(2-methyl-vinyl-pyridinium)41-b-poly(ethylene-oxide)205. This packaging resulted in deviating spectroscopic features of the encapsulated EGFP molecules. Here we show that for monomeric EGFP variant (mEGFP) micellar encapsulation affects the absorption and fluorescence properties to a much lesser extent, and that changes in circular dichroism characteristics are specific for encapsulated EGFP. Time-resolved fluorescence anisotropy of encapsulated (m)EGFP established the occurrence of homo-FRET (Förster resonance energy transfer) with larger transfer correlation times in the case of EGFP. Together, these findings support that EGFP dimerizes whereas the mEGFP mainly remains as a monomer in the densely packed C3Ms. We propose that dimerization of encapsulated EGFP causes a reorientation of Glu222, resulting in a pKa shift of the chromophore, which is fully reversible after release of EGFP from the C3Ms at a high ionic strength.

U2 - 10.1039/c7cp00755h

DO - 10.1039/c7cp00755h

M3 - Article

VL - 19

SP - 11380

EP - 11389

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

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ER -