Structural Basis for Gate-DNA Recognation and Bending by Type IIA Topoisomerases  

Oleh:

Dong, Ken C. ; Berger, James M.

Jenis: Article from Journal - ilmiah internasional
Dalam koleksi: NATURE (keterangan: ada di Proquest) vol. 450 no. 7173 (Dec. 2007), page 1201.

Ketersediaan

Perpustakaan FK Nomor Panggil: N01.K.2 Non-tandon: 1 (dapat dipinjam: 0) Tandon: tidak ada

Lihat Detail Induk

Isi artikel

Type II topoisomerase disentangle DNA to facilitate chromosome segregation, and represent a major class of therapeutic targets. Although these enzymes have been studied extensively, a molecular understanding of DNA binding has been lacking. Here we present the structure of a complex between the DNA-binding and cleavage core of Saccharomyces cerevisiaea Topo II (also known as Top2) and a gate DNA segment. The structure reveals that the enzyme enforces a 150 DNA bend through a mechanism similar to that of remodelling proteins such as integration host factor. Large protein conformational changes accompany DNA deformation, creating a bipartite catalytic site that positions the DNA backbone near a reactive tyrosine and a coordinated magnesium ion. This configuration closely resembles the catalytic site of type I1 topoisomerases, reinforcing an evolutionary link between these structurally and functionally distinct enzymes. Binding of DNA facilitates opening of an enzyme dimerization interface, providing visual evidence for a key step in DNA transport.

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