Document Type

Journal Article

Department/Unit

Department of Chemistry

Title

A label-free G-quadruplex-based luminescent switch-on assay for the selective detection of histidine

Language

English

Abstract

A label-free G-quadruplex-based luminescent switch-on assay has been developed for the selective detection of micromolar histidine in aqueous solution. In this study, an iridium(III) complex was employed as a G-quadruplex-specific luminescent probe while a guanine-rich oligonucleotide (Pu27, 5'-TG4AG3TG4AG3TG4A2G2-3')/cupric ion (Cu2+) ensemble was employed as a recognition unit for histidine. The initial luminescence of the iridium(III) complex in the presence of G-quadruplex DNA is effectively quenched by Cu2+ ions due to the Cu2+-mediated unfolding of the G-quadruplex motif. The addition of histidine sequesters Cu2+ ions from the ensemble, thereby restoring the luminescence of the system. The assay could detect down to 1μM of histidine in aqueous media, and also exhibited good selectivity for histidine over other amino acids with the use of the cysteine, masking agent N-ethylmaleimide. Furthermore, the application of the assay for the detection of histidine in diluted urine samples was demonstrated. © 2013 Elsevier Inc.

Keywords

Cu2+, G-quadruplex, Histidine, Iridium(III) complex, Label-free, Luminescence

Publication Date

2013

Source Publication Title

Methods

Volume

64

Issue

3

Start Page

205

End Page

211

Publisher

Elsevier

DOI

10.1016/j.ymeth.2013.07.023

Link to Publisher's Edition

http://dx.doi.org/10.1016/j.ymeth.2013.07.023

ISSN (print)

10462023

ISSN (electronic)

10959130

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