Tuning the pKa of Carboxyfluorescein with Arginine-Rich Cell-Penetrating Peptides for Intracellular pH Imaging

Autor:	Xinrong Zhang, Sichun Zhang, Meng-Chan Xia, Lesi Cai, Yan Yang
Rok vydání:	2019
Předmět:	chemistry.chemical_compound Fluorophore Aqueous solution chemistry Membrane permeability Arginine Intracellular pH Biophysics Cationic polymerization Conjugated system Fluorescence Analytical Chemistry
Zdroj:	Analytical Chemistry. 91:9168-9173
ISSN:	1520-6882 0003-2700
DOI:	10.1021/acs.analchem.9b01864
Popis:	5-Carboxylfluorescein (FAM) is a conventional pH-responsive fluorophore widely used in fluorescence labeling and imaging. Because of its nonfluorescent structure under acidic conditions, FAM has long been limited to pH determination in a neutral–basic environment. Here, we modified the optical properties of FAM with cationic arginine-rich cell-penetrating peptides (CPPs), tuning the pKa value of FAM to adapt well to pH measurement under diverse pH conditions. With increasing length of polyarginine, the pKa value of FAM was tuned from 6.20 ± 0.06 to 5.17 ± 0.05. The key mechanism for pKa variations was attributed to intramolecular electrostatic attraction and the positive charge of cationic CPPs tend to stabilize the fluorescent dianionic form of FAM. Apart from tunable pKa, arginine-rich CPPs also improved the water solubility, membrane permeability, and organelle-specific localization of FAM. Two conjugated probes FAM-R12 and FAM-(Fxr)3 were selected to monitor intracellular pH fluctuations. Compared to ...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::5edaf6b2450043540e3aeaa46ae74e9c https://doi.org/10.1021/acs.analchem.9b01864 Zobrazit plný text záznamu