阿非科林对真核生物DNA聚合酶α的抑制作用模式。

The mode of inhibitory action by aphidicolin on eukaryotic DNA polymerase alpha.

作者信息

Oguro M, Suzuki-Hori C, Nagano H, Mano Y, Ikegami S

出版信息

Eur J Biochem. 1979 Jul;97(2):603-7. doi: 10.1111/j.1432-1033.1979.tb13149.x.

DOI:10.1111/j.1432-1033.1979.tb13149.x

Abstract

The mode of action by aphidicolin on DNA polymerase alpha from the nuclear fraction of sea-urchin blastulae was studied. The inhibition of DNA polymerase alpha by aphidicolin was uncompetive with activated DNA and competitive with the four deoxynucleoside triphosphates using activated DNA as a template-primer. For truncated (residual or limited) DNA synthesis with only three deoxynucleoside triphosphates, aphidicolin inhibited the residual synthesis more strongly in the absence of dCTP than in the absence of each of the other three deoxynucleoside triphosphates. The inhibition was reversed with excess dCTP but not with the other three deoxynucleoside triphosphates. That is, aphidicolin inhibited DNA polymerase alpha by competing with dCTP with a Ki value of 0.5 microgram/ml and by not competing with the other three deoxynucleoside triphosphates. dTMP incorporation with the activated DNA was more sensitive to aphidicolin than dGMP or dTMP incorporation with poly(dC). (dG)12-18 or poly(dA) . (dT)12-18. Similar results were obtained for DNA polymerase alpha (B form) from mouse myeloma MOPC 104E.

摘要

研究了阿非科林对海胆囊胚细胞核部分DNA聚合酶α的作用方式。以活化DNA为模板引物时，阿非科林对DNA聚合酶α的抑制作用对活化DNA是非竞争性的，对四种脱氧核苷三磷酸是竞争性的。对于仅含三种脱氧核苷三磷酸的截短（残留或有限）DNA合成，在缺乏dCTP时，阿非科林对残留合成的抑制作用比对缺乏其他三种脱氧核苷三磷酸中的任何一种时更强。这种抑制作用可被过量的dCTP逆转，但不能被其他三种脱氧核苷三磷酸逆转。也就是说，阿非科林通过与dCTP竞争抑制DNA聚合酶α，其Ki值为0.5微克/毫升，且不与其他三种脱氧核苷三磷酸竞争。与活化DNA的dTMP掺入相比，阿非科林对与聚（dC）、（dG）12 - 18或聚（dA）·（dT）12 - 18的dGMP或dTMP掺入更敏感。从小鼠骨髓瘤MOPC 104E获得的DNA聚合酶α（B型）也得到了类似结果。