scholarly journals Simultaneously monitoring DNA binding and helicase-catalyzed DNA unwinding by fluorescence polarization

2003 ◽  
Vol 31 (14) ◽  
pp. 70e-70 ◽  
Author(s):  
H. Q. Xu
Keyword(s):  
Dna Binding ◽  
Fluorescence Polarization ◽  
Dna Unwinding

Binding mode and affinity studies of DNA-binding agents using topoisomerase I DNA unwinding assay

2007 ◽  
Vol 17 (4) ◽  
pp. 1013-1017 ◽  
Author(s):  
Ruel E. McKnight ◽  
Aaron B. Gleason ◽  
James A. Keyes ◽  
Sadia Sahabi
Keyword(s):  
Dna Binding ◽  
Topoisomerase I ◽  
Binding Mode ◽  
Dna Unwinding ◽  
Binding Agents ◽  
Dna Binding Agents

scholarly journals Screening antiproliferative drug for breast cancer from bisbenzylisoquinoline alkaloid tetrandrine and fangchinoline derivatives by targeting BLM helicase

BMC Cancer ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Wangming Zhang ◽  
Shuang Yang ◽  
Jinhe Liu ◽  
Linchun Bao ◽  
He Lu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Dna Binding ◽  
Small Molecules ◽  
Cancer Cells ◽  
Small Molecule ◽  
Breast Cancer Cells ◽  
Dna Unwinding ◽  
Protein Levels ◽  
Blm Helicase ◽  
Bisbenzylisoquinoline Alkaloids

Abstract Background The high expression of BLM (Bloom syndrome) helicase in tumors involves its strong association with cell expansion. Bisbenzylisoquinoline alkaloids own an antitumor property and have developed as candidates for anticancer drugs. This paper aimed to screen potential antiproliferative small molecules from 12 small molecules (the derivatives of bisbenzylisoquinoline alkaloids tetrandrine and fangchinoline) by targeting BLM642–1290 helicase. Then we explore the inhibitory mechanism of those small molecules on proliferation of MDA-MB-435 breast cancer cells. Methods Fluorescence polarization technique was used to screen small molecules which inhibited the DNA binding and unwinding of BLM642–1290 helicase. The effects of positive small molecules on the ATPase and conformation of BLM642–1290 helicase were studied by the malachite green-phosphate ammonium molybdate colorimetry and ultraviolet spectral scanning, respectively. The effects of positive small molecules on growth of MDA-MB-435 cells were studied by MTT method, colony formation and cell counting method. The mRNA and protein levels of BLM helicase in the MDA-MB-435 cells after positive small molecule treatments were examined by RT-PCR and ELISA, respectively. Results The compound HJNO (a tetrandrine derivative) was screened out which inhibited the DNA binding, unwinding and ATPase of BLM642–1290 helicase. That HJNO could bind BLM642–1290helicase to change its conformationcontribute to inhibiting the DNA binding, ATPase and DNA unwinding of BLM642–1290 helicase. In addition, HJNO showed its inhibiting the growth of MDA-MB-435 cells. The values of IC50 after drug treatments for 24 h, 48 h and 72 h were 19.9 μmol/L, 4.1 μmol/L and 10.9 μmol/L, respectively. The mRNA and protein levels of BLM helicase in MDA-MB-435 cells increased after HJNO treatment. Those showed a significant difference (P < 0.05) compared with negative control when the concentrations of HJNO were 5 μmol/L and 10 μmol/L, which might contribute to HJNO inhibiting the DNA binding, ATPase and DNA unwinding of BLM helicase. Conclusion The small molecule HJNO was screened out by targeting BLM642–1290 helicase. And it showed an inhibition on MDA-MB-435 breast cancer cells expansion.

Optimization of a high-throughput fluorescence polarization assay for STAT5B DNA binding domain-targeting inhibitors

2020 ◽  
Vol 184 ◽  
pp. 113182 ◽  
Author(s):  
Pimyupa Manaswiyoungkul ◽  
Fettah Erdogan ◽  
Olasunkanmi O. Olaoye ◽  
Aaron D. Cabral ◽  
Elvin D. de Araujo ◽  
...  
Keyword(s):  
Dna Binding ◽  
High Throughput ◽  
Fluorescence Polarization ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Fluorescence Polarization Assay

scholarly journals Interaction of HelQ helicase with RPA modulates RPA-DNA binding and stimulates HelQ to unwind DNA through a protein roadblock

2019 ◽  
Author(s):  
Sarah J. Northall ◽  
Tabitha Jenkins ◽  
Denis Ptchelkine ◽  
Vincenzo Taresco ◽  
Christopher D. O. Cooper ◽  
...  
Keyword(s):  
Dna Binding ◽  
Dna Unwinding ◽  
Abasic Site ◽  
Domain Interaction ◽  
Dna Helicases ◽  
Intrinsically Disordered ◽  
Catalytically Active ◽  
Dna Strands ◽  
Dna Strand ◽  
Protein Barrier

ABSTRACTCells reactivate compromised DNA replication forks using enzymes that include DNA helicases for separating DNA strands and remodelling protein-DNA complexes. HelQ helicase promotes replication-coupled DNA repair in mammals in a network of interactions with other proteins. We report newly identified HelQ helicase activities, when acting alone and when interacting with RPA. HelQ helicase was strongly inhibited by a DNA-protein barrier (BamHIE111A), and by an abasic site in the translocating DNA strand. Interaction of HelQ with RPA activated DNA unwinding through the protein barrier, but not through the abasic site. Activation was lost when RPA was replaced with bacterial SSB or DNA binding-defective RPA, RPAARO1. We observed stable HelQ-RPA-DNA ternary complex formation, and present evidence that an intrinsically disordered N-terminal region of HelQ (N-HelQ) interacts with RPA, destabilising RPA-DNA binding. Additionally, SEC-MALS showed that HelQ multimers are converted into catalytically active dimers when ATP-Mg2+ is bound. HelQ and RPA are proposed to jointly promote replication fork recovery by helicase-catalysed displacement of DNA-bound proteins, after HelQ gains access to ssDNA through its N-terminal domain interaction with RPA.

DNA-binding proteins and DNA-unwinding enzymes in eukaryotes

1980 ◽  
Vol 5 (6) ◽  
pp. 154-157 ◽  
Author(s):  
Arturo Falaschi ◽  
Fabio Cobianchi ◽  
Silvano Riva
Keyword(s):  
Dna Binding ◽  
Binding Proteins ◽  
Dna Binding Proteins ◽  
Dna Unwinding

Human Pif1 helicase is a G-quadruplex DNA-binding protein with G-quadruplex DNA-unwinding activity

2010 ◽  
Vol 430 (1) ◽  
pp. 119-128 ◽  
Author(s):  
Cyril M. Sanders
Keyword(s):  
Dna Binding ◽  
Dna Sequences ◽  
Genome Stability ◽  
Dna Helicase ◽  
Dna Unwinding ◽  
Helicase Domain ◽  
Quadruplex Dna ◽  
G4 Dna ◽  
G Quadruplex ◽  
Pif1 Helicase

Pif1 proteins are helicases that in yeast are implicated in the maintenance of genome stability. One activity of Saccharomyces cerevisiae Pif1 is to stabilize DNA sequences that could otherwise form deleterious G4 (G-quadruplex) structures by acting as a G4 resolvase. The present study shows that human Pif1 (hPif1, nuclear form) is a G4 DNA-binding and resolvase protein and that these activities are properties of the conserved helicase domain (amino acids 206–620 of 641, hPifHD). hPif1 preferentially bound synthetic G4 DNA relative to ssDNA (single-stranded DNA), dsDNA (double-stranded DNA) and a partially single-stranded duplex DNA helicase substrate. G4 DNA unwinding, but not binding, required an extended (>10 nucleotide) 5′ ssDNA tail, and in competition assays, G4 DNA was an ineffective suppressor of helicase activity compared with ssDNA. These results suggest a distinction between the determinants of G4 DNA binding and the ssDNA interactions required for helicase action and that hPif1 may act on G4 substrates by binding alone or as a resolvase. Human Pif1 could therefore have a role in processing G4 structures that arise in the single-stranded nucleic acid intermediates formed during DNA replication and gene expression.

scholarly journals The Formation of a Flexible DNA-binding Protein Chain Is Required for Efficient DNA Unwinding and Adenovirus DNA Chain Elongation

2000 ◽  
Vol 275 (52) ◽  
pp. 40897-40903 ◽  
Author(s):  
Bas van Breukelen ◽  
Panagiotis N. Kanellopoulos ◽  
Paul A. Tucker ◽  
Peter C. van der Vliet
Keyword(s):  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Chain Elongation ◽  
Dna Unwinding ◽  
Protein Chain ◽  
Dna Chain
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