1RR8

Structural Mechanisms of Camptothecin Resistance by Mutations in Human Topoisomerase I

1RR8 の概要

• エントリーDOI: 10.2210/pdb1rr8/pdb
• 分子名称: 5'-D(*AP*AP*AP*AP*AP*GP*AP*CP*TP*T*GP*GP*AP*AP*AP*AP*AP*TP*TP*TP*TP*T)-3', 5'-D(*AP*AP*AP*AP*AP*TP*TP*TP*TP*TP*CP*CP*AP*AP*GP*TP*CP*TP*TP*TP*TP*T)-3', DNA topoisomerase I, ... (6 entities in total)
• 機能のキーワード: protein-dna complex, topotecan, camptothecin, nucleic acid, human topoisomerase i, isomerase-dna complex, isomerase/dna
• 由来する生物種: Homo sapiens (human)
• 細胞内の位置: Nucleus, nucleolus: P11387
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 81144.59

構造登録者

Chrencik, J.E.,Staker, B.L.,Burgin, A.B.,Stewart, L.,Redinbo, M.R. (登録日: 2003-12-08, 公開日: 2004-07-06, 最終更新日: 2024-10-30)

主引用文献

Chrencik, J.E.,Staker, B.L.,Burgin, A.B.,Pourquier, P.,Pommier, Y.,Stewart, L.,Redinbo, M.R.
Mechanisms of camptothecin resistance by human topoisomerase I mutations
J.Mol.Biol., 339:773-784, 2004

PubMed Abstract: Human topoisomerase I relaxes superhelical tension associated with DNA replication, transcription and recombination by reversibly nicking one strand of duplex DNA and forming a covalent 3'-phosphotyrosine linkage. This enzyme is the sole target of the camptothecin family of anticancer compounds, which acts by stabilizing the covalent protein-DNA complex and enhancing apoptosis through blocking the advancement of replication forks. Mutations that impart resistance to camptothecin have been identified in several regions of human topoisomerase I. We present the crystal structures of two camptothecin-resistant forms of human topoisomerase I (Phe361Ser at 2.6A resolution and Asn722Ser at 2.3A resolution) in ternary complexes with DNA and topotecan (Hycamtin), a camptothecin analogue currently in widespread clinical use. While the alteration of Asn722 to Ser leads to the elimination of a water-mediated contact between the enzyme and topotecan, we were surprised to find that a well-ordered water molecule replaces the hydrophobic phenylalanine side-chain in the Phe361Ser structure. We further consider camptothecin-resistant mutations at seven additional sites in human topoisomerase I and present structural evidence explaining their possible impact on drug binding. These results advance our understanding of the mechanism of cell poisoning by camptothecin and suggest specific modifications to the drug that may improve efficacy.

PubMed: 15165849
DOI: 10.1016/j.jmb.2004.03.077

実験手法

X-RAY DIFFRACTION (2.6 Å)