title: A highly sensitive and selective competition assay for the detection of cysteine using mercury-specific DNA, Hg and Sybr Green I.
abstract: We here report a rapid, sensitive, selective and label-free fluorescence detection method for cysteine (Cys). The conformation of mercury-specific DNA (MSD) changes from a random coil form to a hairpin structure in the presence of Hg2+ due to the formation of a thymine-Hg2+ -thymine (T-Hg2+ -T) complex. Cys can selectively coordinate with Hg2+ and extract it from the thymine-Hg2+ -thymine complex. The hairpin structure dehybridizes and the fluorescence intensity of Sybr Green I (SG) decreases upon addition of Cys because SG efficiently discriminates mercury-specific DNA and mercury-specific DNA/Hg2+ complex. The detection can be finished within 5 min with high sensitivity and selectivity. In addition, we can obtain variable dynamic ranges for Cys by changing the concentration of MSD/Hg2+.
authors.affiliation: School of Chemistry and Material Sciences, Ludong University, Yantai 264025, China. xuhui@ldu.edu.cn
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
authors.forename: Shuli
authors.initials: S
authors.lastname: Gao
authors.forename: Quanwen
authors.initials: Q
authors.lastname: Liu
authors.forename: Dun
authors.initials: D
authors.lastname: Pan
authors.forename: Lihua
authors.initials: L
authors.lastname: Wang
authors.forename: Shuzhen
authors.initials: S
authors.lastname: Ren
authors.forename: Min
authors.initials: M
authors.lastname: Ding
authors.forename: Jingwen
authors.initials: J
authors.lastname: Chen
authors.forename: Gang
authors.initials: G
authors.lastname: Liu
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D001483:Base Sequence; D052160:Benzothiazoles; D015374:Biosensing Techniques / Q000379:methods*; D003545:Cysteine / Q000032:analysis* / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D003959:Diamines; D005978:Glutathione / Q000737:chemistry; D008628:Mercury / Q000737:chemistry* / Q000494:pharmacology; D009690:Nucleic Acid Conformation / Q000187:drug effects; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D009930:Organic Chemicals / Q000737:chemistry*; D011804:Quinolines; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence
chemical_list: D000596:Amino Acids; D052160:Benzothiazoles; D003959:Diamines; D009838:Oligodeoxyribonucleotides; D009930:Organic Chemicals; D011804:Quinolines; C098022:SYBR Green I; D004247:DNA; D008628:Mercury; D005978:Glutathione; D003545:Cysteine