» Articles » PMID: 26690153

Modulation of Intracellular Quantum Dot to Fluorescent Protein Förster Resonance Energy Transfer Via Customized Ligands and Spatial Control of Donor-Acceptor Assembly

Overview
Journal Sensors (Basel)
Publisher MDPI
Specialty Biotechnology
Date 2015 Dec 23
PMID 26690153
Authors
Affiliations
Soon will be listed here.
Abstract

Understanding how to controllably modulate the efficiency of energy transfer in Förster resonance energy transfer (FRET)-based assemblies is critical to their implementation as sensing modalities. This is particularly true for sensing assemblies that are to be used as the basis for real time intracellular sensing of intracellular processes and events. We use a quantum dot (QD) donor -mCherry acceptor platform that is engineered to self-assemble in situ wherein the protein acceptor is expressed via transient transfection and the QD donor is microinjected into the cell. QD-protein assembly is driven by metal-affinity interactions where a terminal polyhistidine tag on the protein binds to the QD surface. Using this system, we show the ability to modulate the efficiency of the donor-acceptor energy transfer process by controllably altering either the ligand coating on the QD surface or the precise location where the QD-protein assembly process occurs. Intracellularly, a short, zwitterionic ligand mediates more efficient FRET relative to longer ligand species that are based on the solubilizing polymer, poly(ethylene glycol). We further show that a greater FRET efficiency is achieved when the QD-protein assembly occurs free in the cytosol compared to when the mCherry acceptor is expressed tethered to the inner leaflet of the plasma membrane. In the latter case, the lower FRET efficiency is likely attributable to a lower expression level of the mCherry acceptor at the membrane combined with steric hindrance. Our work points to some of the design considerations that one must be mindful of when developing FRET-based sensing schemes for use in intracellular sensing.

References
1.
Lange A, Mills R, Lange C, Stewart M, Devine S, Corbett A . Classical nuclear localization signals: definition, function, and interaction with importin alpha. J Biol Chem. 2006; 282(8):5101-5. PMC: 4502416. DOI: 10.1074/jbc.R600026200. View

2.
Dif A, Boulmedais F, Pinot M, Roullier V, Baudy-Floch M, Coquelle F . Small and stable peptidic PEGylated quantum dots to target polyhistidine-tagged proteins with controlled stoichiometry. J Am Chem Soc. 2009; 131(41):14738-46. DOI: 10.1021/ja902743u. View

3.
Fessenden J . Förster resonance energy transfer measurements of ryanodine receptor type 1 structure using a novel site-specific labeling method. PLoS One. 2009; 4(10):e7338. PMC: 2757896. DOI: 10.1371/journal.pone.0007338. View

4.
Susumu K, Oh E, Delehanty J, Blanco-Canosa J, Johnson B, Jain V . Multifunctional compact zwitterionic ligands for preparing robust biocompatible semiconductor quantum dots and gold nanoparticles. J Am Chem Soc. 2011; 133(24):9480-96. DOI: 10.1021/ja201919s. View

5.
Resch-Genger U, Grabolle M, Cavaliere-Jaricot S, Nitschke R, Nann T . Quantum dots versus organic dyes as fluorescent labels. Nat Methods. 2008; 5(9):763-75. DOI: 10.1038/nmeth.1248. View