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Titolo:
Substrate specificity plays an important role in uncoupling the catalytic and scaffolding activities of rat testis DNA topoisomerase II alpha
Autore:
Bakshi, R; Galande, S; Muniyappa, K;
Indirizzi:
Indian Inst Sci, Dept Biochem, Bangalore 560012, Karnataka, India Indian Inst Sci Bangalore Karnataka India 560012 560012, Karnataka, India
Titolo Testata:
JOURNAL OF BIOMOLECULAR STRUCTURE & DYNAMICS
fascicolo: 5, volume: 18, anno: 2001,
pagine: 749 - 760
SICI:
0739-1102(200104)18:5<749:SSPAIR>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
MITOTIC CHROMOSOMES; MAMMALIAN-CELLS; CLEAVAGE; BINDING; CYCLE; LOCALIZATION; SEQUENCE; REGION; GENE; INVOLVEMENT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
45
Recensione:
Indirizzi per estratti:
Indirizzo: Muniyappa, K Indian Inst Sci, Dept Biochem, Bangalore 560012, Karnataka, India Indian Inst Sci Bangalore Karnataka India 560012 taka, India
Citazione:
R. Bakshi et al., "Substrate specificity plays an important role in uncoupling the catalytic and scaffolding activities of rat testis DNA topoisomerase II alpha", J BIO STRUC, 18(5), 2001, pp. 749-760

Abstract

Topoisomerase II (topo II) is a dyadic enzyme found in ail eukaryotic cells. Topo II is involved in a number of cellular processes related to DNA metabolism, including DNA replication, recombination and the maintenance of genomic stability. We discovered a correlation between the development of postnatal testis and increased binding of topo II alpha to the chromatin fraction. We used this observation to characterize DNA-binding specificity and catalytic properties of purified testis topo II alpha. The results indicate that topo II alpha binds a substrate containing the preferred site with greater affinity and, consequently, catalyzes the conversion of form I to formIV DNA more efficiently in contrast to substrates lacking such a site. Interestingly, topo II alpha displayed high-affinity and cooperativity in binding to the scaffold associated region. In contrast to the preferred site, however, high-affinity binding of topo II alpha to the scaffold-associated region failed to result in enhanced catalytic activity. Intriguingly, competition assays involving scaffold-associated region revealed an additional DNA-binding site within the dyadic topo II alpha. These results implicate a dual role for topo II alpha in vivo consistent with the notion that its sequestration to the chromatin might play a role in chromosome condensation anddecondensation during spermatogenesis.

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Documento generato il 13/07/20 alle ore 18:04:44