title: Highly sensitive photoelectrochemical assay for DNA methyltransferase activity and inhibitor screening by exciton energy transfer coupled with enzyme cleavage biosensing strategy.
abstract: Highly sensitive DNA methyltransferase (MTase) activity and inhibitor screening photoelectrochemical (PEC) assay was developed based on the exciton energy transfer (EET) effect coupled with site-specific cleavage of restriction endonuclease (HpaII). The assay was designed by integrating the Au nanoparticles (NPs) labeled probe DNA (pDNA-Au) with CdSe quantum dots (QDs). The strong EET effect between Au NPs and CdSe QDs resulted in the dramatic decrease of photocurrent signal. The pDNA carried a sensing region for specifically recognizing target DNA (tDNA) and hybridizing with it to form a DNA duplex. With the site-specific cleavage of HpaII, the DNA duplex could be cleaved and Au NPs would be released, which broke the EET and resulted in the restoration of photocurrent signal. However, when the DNA duplex was methylated by M.SssI MTase, this cleavage of HpaII was blocked, and therefore the unbroken EET effect kept the lower photocurrent signal. That was, the restored photocurrent was inversely proportional to the MTase activity. Based on this strategy, the PEC assay could determine as low as ~0.0042 U/mL of M.SssI MTase with a linear range from 0.01 to 150 U/mL. In addition, the assay could be used for the screening of the inhibitors of MTase. This PEC assay provides a promising platform for monitoring the activity and inhibition of DNA MTase, and thus shows a great potential in cancer diagnostics and anti-cancer drugs discovery.
authors.affiliation: Key Lab of Organic Electronics & Information Displays, Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, PR China. Electronic address: iamqmshen@njupt.edu.cn.
authors.forename: Qingming
authors.initials: Q
authors.lastname: Shen
authors.affiliation: Key Lab of Organic Electronics & Information Displays, Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, PR China; State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Han
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
authors.forename: Gaochao
authors.initials: G
authors.lastname: Fan
authors.affiliation: Petrochemical Research Chair, Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Kingdom of Saudi Arabia.
authors.forename: E S
authors.initials: ES
authors.lastname: Abdel-Halim
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China. Electronic address: jianglp@nju.edu.cn.
authors.forename: Liping
authors.initials: L
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
authors.forename: Jun-Jie
authors.initials: JJ
authors.lastname: Zhu
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004247:DNA / Q000032:analysis / Q000737:chemistry* / Q000235:genetics; D004791:Enzyme Inhibitors / Q000032:analysis / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D031541:Fluorescence Resonance Energy Transfer / Q000295:instrumentation*; D008780:Methyltransferases / Q000032:analysis / Q000737:chemistry* / Q000235:genetics
chemical_list: D004791:Enzyme Inhibitors; D004247:DNA; D008780:Methyltransferases
keywords: DNA methylation; Enzyme cleavage; Exciton energy transfer; Methyltransferase; Photoelectrochemistry