A study of BLM A5 was conducted using a previously isolated library of hairpin DNAs found to bind strongly to metal-free BLM. The ability of Fe(II)·BLM to affect cleavage on both the 3' and 5' arms of the hairpin DNAs was characterized. The strongly bound DNAs were found to be efficient substrates for Fe·BLM A5-mediated hairpin DNA cleavage. Surprisingly, the most prevalent site of BLM-mediated cleavage was found to be the 5'-AT-3' dinucleotide sequence. This dinucleotide sequence and other sequences generally not cleaved well by BLM when examined using arbitrarily chosen DNA substrates were apparent when examining the library of 10 hairpin DNAs. In total, 132 sites of DNA cleavage were produced by exposure of the hairpin DNA library to Fe·BLM A5. The existence of multiple sites of cleavage on both the 3' and 5' arms of the hairpin DNAs suggested that some of these might be double-strand cleavage events. Accordingly, an assay was developed to test the propensity of the hairpin DNAs to undergo double-strand DNA damage. One hairpin DNA was characterized using this method and gave results consistent with earlier reports of double-strand DNA cleavage but with a sequence selectivity that was different from those reported previously.
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http://dx.doi.org/10.1021/bi400779r | DOI Listing |
Talanta
January 2025
College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, Shandong, 252000, China. Electronic address:
MicroRNAs (miRNAs) are closely associated with cancer and have been considered cancer biomarkers. Herein, we propose an electrochemiluminescence (ECL) biosensor for detecting miRNA-21 based on target-induced catalytic hairpin self-assembly (CHA) and CuO-mediated azide-alkyne cycloaddition. Two hairpin DNAs were employed: one was immobilized on magnetic beads (HP2) and another was labeled with CuO (HP1-CuO).
View Article and Find Full Text PDFAnal Chem
September 2024
Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P. R. China.
In this work, by ingeniously integrating catalytic hairpin assembly (CHA), double-end Mg-dependent DNAzyme, and hybridization chain reaction (HCR) as a triple cascade signal amplifier, an efficient concatenated CHA-DNAzyme-HCR (CDH) system was constructed to develop an ultrasensitive electrochemical biosensor with a low-background signal for the detection of microRNA-221 (miRNA-221). In the presence of the target miRNA-221, the CHA cycle was initiated by reacting with hairpins H1 and H2 to form DNAzyme structure H1-H2, which catalyzed the cleavage of the substrate hairpin H0 to release two output DNAs (output 1 and output 2). Subsequently, the double-loop hairpin H fixed on the electrode plate was opened by the output DNAs, to trigger the HCR with the assistance of hairpins Ha and Hb.
View Article and Find Full Text PDFAnal Chem
August 2024
Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China.
miR-155 is a class of cancer markers closely related to cancer metastasis and invasion. Combining in situ detection with gene silencing not only helps to analyze the information on the abundance and spatial location of microRNA expression in the cell but also synergizes the therapy. In this work, we prepared HD@CM vesicles with three hairpin DNAs by using MCF-7 cell membranes.
View Article and Find Full Text PDFOrg Biomol Chem
August 2024
Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune 411008, India.
Nucleic acids (DNA and RNA) can form diverse secondary structures ranging from hairpins to duplex, triplex, G4-tetraplex and C4-i-motifs. Many of the DNA analogues designed as antisense oligonucleotides (ASO) are also adept at embracing such folded structures, although to different extents with altered stabilities. One such analogue, peptide nucleic acid (PNA), which is uncharged and achiral, forms hybrids with complementary DNA/RNA with greater stability and specificity than DNA:DNA/RNA hybrids.
View Article and Find Full Text PDFBiochem Genet
July 2024
State Key Laboratory of Food Science and Resource, Nanchang University, Nanchang, 330047, China.
As a tool for acquiring uncharacterized genomic DNA adjacent to characterized DNA, genome-walking is integral to bioscience-related research works. Herein, a new genome-walking tool known as N-ended walker PCR (polymerase chain reaction) is presented. The key aspect for this method is the use of a degenerate walker primer in secondary/tertiary PCR.
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