4ZVM

Oxidized quinone reductase 2 in complex with doxorubicin

4ZVM の概要

• エントリーDOI: 10.2210/pdb4zvm/pdb
• 関連するPDBエントリー: 4ZVK 4ZVL 4ZVN
• 分子名称: Ribosyldihydronicotinamide dehydrogenase [quinone], ZINC ION, FLAVIN-ADENINE DINUCLEOTIDE, ... (5 entities in total)
• 機能のキーワード: quinone reductase 2, doxorubicin, oxidoreductase-inhibitor complex, oxidoreductase-oxidoreductase inhibitor complex, oxidoreductase/oxidoreductase inhibitor
• 由来する生物種: Homo sapiens (Human)
• 細胞内の位置: Cytoplasm: P16083
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 54487.63

構造登録者

Leung, K.K.,Shilton, B.H. (登録日: 2015-05-18, 公開日: 2016-03-30, 最終更新日: 2023-09-27)

主引用文献

Leung, K.K.,Shilton, B.H.
Binding of DNA-Intercalating Agents to Oxidized and Reduced Quinone Reductase 2.
Biochemistry, 54:7438-7448, 2015

PubMed Abstract: Quinone reductase 2 (NQO2) is an enzyme that might have intracellular signaling functions. NQO2 can exist in either an oxidized state or a reduced state, and binding of compounds to one or both of these states inhibits enzymatic activity and could also affect intracellular signaling. A wide range of planar aromatic compounds bind NQO2, and we have identified three DNA-intercalating agents [ethidium bromide, acridine orange (AO), and doxorubicin] as novel nanomolar inhibitors of NQO2. Ethidium and AO, which carry a positive charge in their aromatic ring systems, bound reduced NQO2 with an affinity 50-fold higher than that of oxidized NQO2, while doxorubicin bound only oxidized NQO2. Crystallographic analyses of oxidized NQO2 in complex with the inhibitors indicated that the inhibitors were situated deep in the active site. The aromatic faces were sandwiched between the isoalloxazine ring of FAD and the phenyl ring of F178, with their edges making direct contact with residues lining the active site. In reduced NQO2, ethidium and AO occupied a more peripheral position in the active site, allowing several water molecules to interact with the polar end of the negatively charged isoalloxazine ring. We also showed that AO inhibited NQO2 at a nontoxic concentration in cells while ethidium was less effective at inhibiting NQO2 in cells. Together, this study shows that reduced NQO2 has structural and electrostatic properties that yield a preference for binding of planar, aromatic, and positively charged molecules that can also function as DNA-intercalating agents.

PubMed: 26636353
DOI: 10.1021/acs.biochem.5b00884

実験手法

X-RAY DIFFRACTION (1.973 Å)