| Autor: |
Kudriashova NV, Shamanina MIu, Godovikova TS, Anan'ko EA, Akhmadieva FF, Romashchenko AG |
| Jazyk: |
ruština |
| Zdroj: |
Biokhimiia (Moscow, Russia) [Biokhimiia] 1993 Feb; Vol. 58 (2), pp. 224-33. |
| Abstrakt: |
gamma-p-Azidoanilidate of dTTP was used to study the photoaffinity modification of DNA polymerase I and Klenow fragment. The analog was found to be a mixed-type inhibitor with respect to dTTP of the polymerization reaction catalyzed by DNA polymerase I and Klenow fragment. In the absence of the reagent both UV-irradiated enzymes were rapidly inactivated. Substrates (dNTP and template-primer) protected the enzymes from inactivation by UV-light with different efficiency. In the presence of the template-primer UV-irradiation induced activation of DNA polymerase I. The effect of the analog on both enzyme forms under irradiation is different. At concentration of 10(-5)M gamma-p-anilidate of dTTP accelerated the activation of DNA polymerase I initiated by UV-irradiation and at 10(-4)M concentration it inactivated the enzyme by 20-25%. Under such conditions one enzyme molecule covalently bound two molecules of the analog. While the template-complementary substrate (dTTP) protected DNA polymerase I both from inactivation and modification, the non-complementary one (dCTP) worked only against modification. In contrast to DNA polymerase I Klenow fragment was not inactivated when exposed to UV-irradiation and gamma-p-anilidate of dTTP neither modified the protein nor exerted any significant effect on its polymerization activity. The data accumulated suggest the presence on the DNA polymerase I molecule of a regulatory region providing additional dNTP binding sites. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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