Inhibition of DNA Unwinding and ATPase Activities of Human DNA Helicase II by Chemotherapeutic Agents

Tuteja, Narendra; Phan, Tuan‐Nghia; Tuteja, Renu; Ochem, Alexander; Falaschi, Arturo

doi:10.1006/bbrc.1997.7021

Cited by 58 publications

(41 citation statements)

References 16 publications

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“…In E. coli and human helicases, this inhibition has been shown to be highly specific with respect to the ligand used (George et al, 1992;Tuteja et al, 1997). The topoisomerase inhibitor etoposide (VP-16) and the cytotoxic alkaloid camptothecin, which are nonintercalating ligands and do not bind DNA directly, showed no inhibition of the helicase or ATPase activities of ctDNA helicase II.…”

Section: Discussionmentioning

confidence: 99%

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A Chloroplast DNA Helicase II from Pea That Prefers Fork-Like Replication Structures

Tuteja

Phan

1998

Plant Physiology

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A DNA helicase, called chloroplast DNA (ctDNA) helicase II, was purified to apparent homogeneity from pea (Pisum sativum). The enzyme contained intrinsic, single-stranded, DNA-dependent ATPase activity and an apparent molecular mass of 78 kD on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The DNA helicase was markedly stimulated by DNA substrates with fork-like replication structures. A 5-tailed fork was more active than the 3-tailed fork, which itself was more active than substrates without a fork. The direction of unwinding was 3 to 5 along the bound strand, and it failed to unwind blunt-ended duplex DNA. DNA helicase activity required only ATP or dATP hydrolysis. The enzyme also required a divalent cation (Mg 2؉ >Mn 2؉ >Ca 2؉ ) for its unwinding activity and was inhibited at 200 mM KCl or NaCl. This enzyme could be involved in the replication of ctDNA. The DNA major groove-intercalating ligands nogalamycin and daunorubicin were inhibitory to unwinding (K i approximately 0.85 M and 2.2 M, respectively) and ATPase (K i approximately 1.3 M and 3.0 M, respectively) activities of pea ctDNA helicase II, whereas ellipticine, etoposide (VP-16), and camptothecin had no effect on the enzyme activity. These ligands may be useful in further studies of the mechanisms of chloroplast helicase activities.A special class of DNA-interacting enzymes known as DNA helicases catalyze the unwinding of energetically stable duplex DNA in an ATP-dependent manner, and thus play an important role in DNA replication, repair, recombination, and transcription (Matson et al

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Section: Discussionmentioning

confidence: 99%

“…The chemical structures of the ligands used are described in Tuteja et al (1997). Initially, each ligand was used at a final concentration of 50 m. The results are shown in Figure 8.…”

Section: Influence Of Dna-interacting Ligands On Dna Unwinding and Atmentioning

confidence: 99%

A Chloroplast DNA Helicase II from Pea That Prefers Fork-Like Replication Structures

Tuteja

Phan

1998

Plant Physiology

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“…Since imidazo[1,2-a]azaheterocycles such as those in Scheme 3 above may be converted to larger heterocycles that can be expected to intercalate with DNA because of their H-bonding donor and acceptor groups, [8][9][10] this work was extended to bis-isoxazolinyl diazaheterocycles. 2 Structures 1, 2, and 4 are clearly well set up as precursors for polycyclic structures which are of considerable interest as pharmacophores for therapeutic drugs.…”

Section: Methodsmentioning

confidence: 99%

The synthesis of potential DNA intercalators. 3†. Triazanaphthalene, tetraaza anthracene and phenanthrene from isoxazolones

Ebrahimlo¹,

Khalafy²,

Marjani³

et al. 2009

Arkivoc

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“…9,10 In addition, the formation of the isoxazolo[3,2-b]quinazoline 14 opens up intriguing possibilities of carbenoid derived products of novel structure.…”

Section: Methodsmentioning

confidence: 99%

Synthesis of imidazo[1,2-a] pyridines by rearrangement of 2-pyridyl-3-arylaminoisoxazol-5-(2H)-ones

Khalafy¹,

Ebrahimlo²,

Eisavi³

et al. 2005

Arkivoc

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2-Pyridyl-3-arylaminoisoxazol-5(2H)-ones, substituted on N with a nitropyridine group 12a-12e reacted with triethylamine in ethanol under reflux to give imidazo[1,2-a]pyridines 13a-13e and carbon dioxide. An analogous synthesis failed to yield ethyl 3-(2-ethoxycarbonylphenyl) amino-5-oxo-2,5-dihydroisoxazole-4-carboxylate; the reaction of diethyl (2-ethoxycarbonylphenyl)thiocarbamoylmalonate with hydroxylamine gave the novel isoxazolo[3,2-b]quinazoline 14 by intramolecular acylation of the isoxazolone intermediate 14a.

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Inhibition of DNA Unwinding and ATPase Activities of Human DNA Helicase II by Chemotherapeutic Agents

Cited by 58 publications

References 16 publications

A Chloroplast DNA Helicase II from Pea That Prefers Fork-Like Replication Structures

A Chloroplast DNA Helicase II from Pea That Prefers Fork-Like Replication Structures

The synthesis of potential DNA intercalators. 3†. Triazanaphthalene, tetraaza anthracene and phenanthrene from isoxazolones

Synthesis of imidazo[1,2-a] pyridines by rearrangement of 2-pyridyl-3-arylaminoisoxazol-5-(2H)-ones

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