title: Specific detection of the cleavage activity of mycobacterial enzymes using a quantum dot based DNA nanosensor.
abstract: We present a quantum dot based DNA nanosensor specifically targeting the cleavage step in the reaction cycle of the essential DNA-modifying enzyme, mycobacterial topoisomerase I. The design takes advantages of the unique photophysical properties of quantum dots to generate visible fluorescence recovery upon specific cleavage by mycobacterial topoisomerase I. This report, for the first time, demonstrates the possibility to quantify the cleavage activity of the mycobacterial enzyme without the pre-processing sample purification or post-processing signal amplification. The cleavage induced signal response has also proven reliable in biological matrices, such as whole cell extracts prepared from Escherichia coli and human Caco-2 cells. It is expected that the assay may contribute to the clinical diagnostics of bacterial diseases, as well as the evaluation of treatment outcomes.
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus 8000 C, Denmark. megan.ypho@inano.au.dk and Department of Molecular Biology and Genetics, Aarhus University, Aarhus 8000 C, Denmark.
authors.forename: Morten Leth
authors.initials: ML
authors.lastname: Jepsen
authors.affiliation: Department of Molecular Biology and Genetics, Aarhus University, Aarhus 8000 C, Denmark.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Harmsen
authors.affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India.
authors.forename: Adwait Anand
authors.initials: AA
authors.lastname: Godbole
authors.affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India.
authors.forename: Valakunja
authors.initials: V
authors.lastname: Nagaraja
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus 8000 C, Denmark. megan.ypho@inano.au.dk and Department of Molecular Biology and Genetics, Aarhus University, Aarhus 8000 C, Denmark.
authors.forename: Birgitta R
authors.initials: BR
authors.lastname: Knudsen
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus 8000 C, Denmark. megan.ypho@inano.au.dk and Department of Molecular Biology and Genetics, Aarhus University, Aarhus 8000 C, Denmark.
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Ho
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis* / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D018938:Caco-2 Cells; D004247:DNA / Q000737:chemistry*; D004264:DNA Topoisomerases, Type I / Q000032:analysis* / Q000737:chemistry; D006801:Humans; D009161:Mycobacterium / Q000201:enzymology*; D045663:Quantum Dots / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D004247:DNA; D004264:DNA Topoisomerases, Type I