title: Label-free fluorescence strategy for sensitive detection of exonuclease activity using SYBR Green I as probe.
abstract: A label-free and sensitive fluorescence assay for exonuclease activity is developed using commercially available SYBR Green I (SG) dye as signal probe. A proof-of-concept of this assay has been demonstrated by using exonuclease III (Exo III) as a model enzyme. In this assay, double-stranded DNA (dsDNA) can bind SG, resulting in a strong fluorescence signal of SG. Upon the addition of Exo III, dsDNA would be digested, and SG emits very weak fluorescence. Thus, Exo III activity can be facilely measured with a simple fluorescence reader. This method has a linear detection range from 1 U/mL to 200 U/mL with a detection limit of 0.7 U/mL. This label-free approach is selective, simple, convenient and cost-efficient without any complex DNA sequence design or fluorescence dye label. The method not only provides a platform for monitoring activity and inhibition of exonuclease but also shows great potential in biological process researches, drug discovery, and clinic diagnostics.
authors.affiliation: Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China.
authors.forename: Min
authors.initials: M
authors.lastname: Xu
authors.affiliation: Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China. Electronic address: libaoxin@snnu.edu.cn.
authors.forename: Baoxin
authors.initials: B
authors.lastname: Li
mesh_terms: D052160:Benzothiazoles; D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D003959:Diamines; D005090:Exodeoxyribonucleases / Q000378:metabolism*; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D009930:Organic Chemicals / Q000737:chemistry*; D011804:Quinolines; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D052160:Benzothiazoles; D003959:Diamines; D005456:Fluorescent Dyes; D009930:Organic Chemicals; D011804:Quinolines; C098022:SYBR Green I; D004247:DNA; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III
keywords: Exonuclease; Fluorescence; Label-free; SYBR Green I