Substrate specificity plays an important role in uncoupling the catalytic and scaffolding activities of rat testis DNA topoisomerase IIalpha


Autoria(s): Bakshi, R; Galande, S; Muniyappa, K
Data(s)

01/04/2001

Resumo

Topoisomerase II (topo II) is a dyadic enzyme found in all 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 IIalpha to the chromatin fraction. We used this observation to characterize DNA-binding specificity and catalytic properties of purified testis topo IIalpha. The results indicate that topo IIalpha binds a substrate containing the preferred site with greater affinity and, consequently, catalyzes the conversion of form I to form IV DNA more efficiently in contrast to substrates lacking such a site. Interestingly, topo IIalpha displayed high-affinity and cooperativity in binding to the scaffold associated region. In contrast to the preferred site, however, high-affinity binding of topo IIalpha 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 IIalpha. These results implicate a dual role for topo IIalpha in vivo consistent with the notion that its sequestration to the chromatin might play a role in chromosome condensation and decondensation during spermatogenesis.

Formato

application/pdf

Identificador

http://eprints.iisc.ernet.in/25635/1/Substrate_Specificity_Plays_an_Important_10489.pdf

Bakshi, R and Galande, S and Muniyappa, K (2001) Substrate specificity plays an important role in uncoupling the catalytic and scaffolding activities of rat testis DNA topoisomerase IIalpha. In: Journal of Biomolecular Structure & Dynamics, 18 (5). pp. 749-760.

Publicador

Adenine Press

Relação

http://www.jbsdonline.com/Substrate-Specificity-Plays-an-Important-Role-in-Uncoupling-the-Catalytic-and-Scaffolding-Activities-of-Rat-Testis-DNA-Topoisomerase-II-p-749-760-p10489.html

http://eprints.iisc.ernet.in/25635/

Palavras-Chave #Biochemistry
Tipo

Journal Article

PeerReviewed