ANTITUMOR BISDIOXOPIPERAZINES INHIBIT YEAST DNA TOPOISOMERASE-II BY TRAPPING THE ENZYME IN THE FORM OF A CLOSED PROTEIN CLAMP
ANTITUMOR BISDIOXOPIPERAZINES INHIBIT YEAST DNA TOPOISOMERASE-II BY TRAPPING THE ENZYME IN THE FORM OF A CLOSED PROTEIN CLAMP
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DOI：
10.1073/pnas.91.5.1781
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发表时间：
1994-03-01
影响因子：
11.1
通讯作者：
WANG, JC
中科院分区：
文献类型：
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作者：
ROCA, J;ISHIDA, R;WANG, JC
采用纯化的酵母DNA拓扑异构酶II，研究了抗癌药物双氧哌嗪家族成员ICRF-193对真核生物DNA拓扑异构酶II [DNA拓扑异构酶（atb -水解），EC 5.99.1.3]的抑制机制。在没有ATP的情况下，ICRF-193对酶与各种形式DNA的结合几乎没有影响。在ATP存在的情况下，药物将酶转化为不能结合环状DNA的形式。用ICRF-193和ATP孵育预先形成的环状dna -酶复合物，可将该复合物转化为在摩尔盐浓度下稳定的形式。这些结果可以根据atp调节的II型DNA拓扑异构酶蛋白钳模型来解释[Roca， J. & Wang， J. C. (1992) Cell 71, 833-840]；ICRF-193可以与酶的闭夹形式结合，并阻止其转化为开夹形式。这一发现进一步支持了这一解释，尽管ATP和药物都需要形成盐稳定的环状dna -酶复合物，但ATP不需要维持该复合物；此外，如果该酶与ATP和ICRF-193共同培养，则可以观察到该酶的闭钳形式，即金黄色葡萄球菌菌株V8内源性蛋白酶的Glu-680切割位点。抑制II型DNA拓扑异构酶的开夹和闭夹形式之间的相互转化为选择和设计针对这类酶的治疗方法提供了新的机制。
The mechanism of inhibition of eukaryotic DNA topoisomerase II [DNA topoisomerase (ATB-hydrolyzing), EC 5.99.1.3] by a member of the bisdioxopiperazine family of anticancer drugs, ICRF-193, was investigated by using purified yeast DNA topoisormerase II. In the absence of ATP, ICRF-193 has little effect on the binding of the enzyme to various forms of DNA. In the presence of ATP, the drug converts the enzyme to a form incapable of binding circular DNA. Incubation of a preformed circular DNA-enzyme complex with ICRF-193 and ATP converts the complex to a form stable in molar concentrations of salt. These results can be interpreted in terms of the ATP-modulated protein-clamp model of type II DNA topoisomerases [Roca, J. & Wang, J. C. (1992) Cell 71, 833-840]; ICRF-193 can bind to the closed-clamp form of the enzyme and prevents its conversion to the open-clamp form. This interpretation is further supported by the finding that whereas both ATP and the drug are needed to form the salt-stable circular DNA-enzyme complex, ATP is not needed for maintaining this complex; furthermore, a signature of the closed-clamp form of the enzyme, Staphylococcus aureus strain V8 endoproteinase cleavage site at Glu-680, is observed if the enzyme is incubated with both ATP and ICRF-193. Inhibition of interconversion between the open and closed-clamp forms of type II DNA topoisomerases offers a new mechanism in the selection and design of therapeutics targeting this class of enzymes.